Nature & News

Winter in Yosemite

Winter is the quiet time in Yosemite. Days are short, there are fewer visitors and many of the animals spend a lot of their time hidden. Ground squirrels, bears and, of course, cold-blooded animals hunker down in hibernation or torpor for the winter. In very cold places, toads will burrow as deep as three feet to hibernate.

Some animals are active all winter, but nevertheless usually hidden. Meadow voles and mice live out much of their winters in the space that forms between the snowpack and the ground, the subnivean layer. There the warmth from the ground and the insulating layer of the snow keep the temperatures around freezing and the snow protects them from the elements. Unfortunately for the mice and voles, though, long-tailed weasels are well-adapted to hunt in the subnivean layer with their long, skinny bodies and keen sense of smell.

Despite the seeming quiet, there is still a lot going on above the ground. Coyotes and bobcats hunt the meadows when snow cover is thin. Using their acute senses of hearing and smell, they locate animals below the surface and then pounce. The coyote makes a big arcing jump, coming down mouth first, diving into the snow and fairly regularly coming up with a small meal.

The Time Machine

The real pleasure of the winter, though, is the winter time machine – animal tracks. Why are tracks a time machine? Because they allow us to go back in time and see what has happened in the forest since the last snow. One of our winter pleasures is putting on our skis and getting out into the woods shortly after a storm. It’s often surprising how much activity there has been, even in just a few hours after the end of the storm. So while the cold and snow make harder to see animals, it is far easier to see signs showing which animals have recently been out and about and where they were going.

Squirrels

We know, a lot of people are not fans of squirrels, but they are nearly ubiquitous in North America so almost everyone who lives in a place with snow can track them. And squirrels are fascinating animals, fun to watch and to track, especially Theresa’s favorite animal, the chickaree or Douglas squirrel (Tamiasciurus douglasii), a close relative of the more widely-distributed red squirrel (Tamiasciurus hudsonicus). How could you not want to track this guy?

The first thing to notice about squirrels is just how active they are as soon as the storm ends. On a sunny morning after a night of snowfall, the tracks will be everywhere. In the deep cold of winter nights, squirrels often congregate in group nests to stay warm, with males and females gathering in separate nests. But when day breaks, they are out and about. We actually see very few of them compared to summer, but the tracks let you peer into the past to see what they’ve been up to since the end of the storm.

Squirrel tracks also tell the story of how squirrels travel in snow. One thing to note is that the hind feet land in front of the forefeet when squirrels are bounding. Also tracks typically connect tree to tree, rarely passing through any real distance in the open. In soft snow, the squirrels climb a few feet up the tree and then hurl themselves off. We sometimes like to set our skis next to the tracks to estimate just how far they jump. Tom skis a 165cm (roughly 65-inch) ski and the jumps are commonly longer than his skis, so six or more feet.

Why? In soft snow, squirrels are slow waders/paddlers and easy prey. They look like they are swimming, which effectively they are, which makes them slow and vulnerable in light snow. Being such agile climbers and jumpers, it takes less energy and reduces the amount of time they spend out exposed to raptors, bobcats and coyotes if they climb up a few feet and get the next six feet of travel practically for free and almost instantly and then race to the next safe spot.

In very deep snow, they can get even more creative. One time Tom was out alone in one of our favorite spots and in his far peripheral vision he saw what he first thought was a raptor diving from the sky. Instead, it was a squirrel coming in for a landing in what seemed like open ground. The squirrel had walked out along a branch that was maybe 10 feet long and 15 feet up and hurled itself off. In so doing it covered most of the 20 feet between the tree it started on and the sheltering branches of a young sapling buried in snow. As soon as it hit the ground, it started paddling through the snow like it was swimming in a race and soon reached the sapling. The gaps in the snowpack created by the branches of the sapling gave it ready access to the world beneath the snow and down it went, within a few seconds safe from surface hunters.

It’s rare that we get to see these travel jumps, but the tracks tell the tale. It’s easy to ignore such a common animal, but that very ubiquity is one of the things that makes it fun — you don’t have to be a squirrel whisperer to find some tracks to follow.

The great thing about tree squirrels is that they are active all winter and numerous. So it’s rare to go out in freshly-fallen snow and not be able to at least find a squirrel track to follow and study. And there always seems to be something new to learn even from this most common animal.

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Mountain Lion Tracks

In 20 years of living in Yosemite, neither of us has seen a mountain lion (cougar, puma), but fresh tracks in the snow right after a storm sometimes tell us that we have missed a cougar by less than two hours.

One time we saw impressively large cougar tracks come to a set of manzanita bushes. The group of bushes was about fifteen feet in diameter but only a couple feet tall. You would think the easy thing to do would be to a go around, but apparently not. We could see the normal walking track of the lion then, as it approached the bushes, the forefeet and hindfeet bunching together as the cat readied to spring, then nothing. On the other side, we found the bunched tracks of the landing, then back to walking along on its merry way. It looked like the 15-20-foot jump was as trivial as a yawn, not even worth a 20-foot detour to avoid. Sure, we never saw the actual cat, but the tracks gave us a feel for the awesome agility and power of the animal and our minds recreated the scene almost as if we had seen the cat itself.

On another occasion, Tom went for a morning run after a small dusting of snow from the night day and saw not one, not two, but three parallel sets of cougar tracks. That meant there were either three cats in the woods or one cat that has passed by three times in less than twelve hours. Both possibilities were sobering. He spent the rest of the run yelling and making noise (a few months later a park service game camera in the area captured three cats traveling together, probably a mother and two daughters).

While we have seen mountain lion tracks many times in the snow, we only have the one good photo (above). But we have taken some pictures of tracks here in Yosemite West. Note the three-lobed rear pad and the round footprint, clear signs of a cat.

Again, despite countless hours and miles in the forest and despite dozens of sightings of tracks, neither of us has ever seen one of these cats in the wild. But by paying attention to the tracks that let us go back in time and see who was in the woods shortly before us, we have had several “sightings” of mountain lions, disconnected in time.

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Bear Tracks in Winter

Many people think bears hibernate all winter and are never active. We have seen bears down in Yosemite Valley in February feeding on a deer carcass from a mountain lion kill. If there’s food, males and non-pregnant females do not need to hibernate (technically, enter torpor as bears are not true hibernators). Up higher, at our house and above, there is almost never enough winter food, so all bears den up for the winter And yet, every winter, we see bear tracks in the snow.

Bears, as it turns out, do not have watches or iPhones to tell them what day it is, so if they don’t have a den full of cubs, they get up and take a walk and, finding inadequate food, go back into torpor. They might also be out and about if their den was damaged or flooded and need to find a new place to bed down. In any case, we have never seen a high-country bear in winter, but we have seen their tracks in just about every month of the winter.

November

December

January

These are not as clear in the photo, but they are certainly bear tracks, certainly from January (2018) and sort of neat in that if you look you can see the claw marks.

February

We didn’t find any photos of March bear tracks in our library, but there might be some lurking there. In any case, we have seen bears or bear tracks in virtually every month, including not just in Yosemite Valley but up in the higher elevations. The February photos are from elevations of roughly 7000 and 8000 feet, respectively, with a heavy snowpack on the ground.

Also note that you can find bear “tracks” other places than the ground. Sometimes they scratch trees. One theory is that they are trying to show other bears how big they are so they can scare smaller bears off their territory. Not sure if that is just an old myth or has any real research behind it.

Interestingly, in this very snowy winter of 2023 we have been getting out more than usual, and yet we have seen no bear tracks since early December. Apparently very deep snowpacks makes for good sleeping.

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Following a Fox and a Bobcat

One of our best tracking expeditions came after an early-season storm that dropped just a few inches of snow on otherwise bare ground. That meant we didn’t need skis and could follow tracks through thick forest. We soon found a fox track and followed it for a couple of hours which, at the slow pace we were going, was only about a mile and a half. Nevertheless, we learned a bit about foxes that day. In particular, the agility of this fox was incredible. It would jump up on a narrow log covered in snow and walk on it for a while before jumping down and continuing on. No terrain seemed to be an obstacle. At one point, a bobcat crossed the fox track. It tried to jump up on the same log as the fox, but could not match the fox’s agility and we saw the wide mark where it fell and slid down the far side of the log.

Unfortunately, we didn’t take pictures that day so we don’t have fox or bobcat tracks to show, but if you wander the woods enough, you might find your own!

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Martens and Weasels

We have a “go to” area for quick hit ski tours close to the house which we have now been touring for 20 years. Conservatively, we have been there 100 times. Probably closer to 200. A couple years ago we first saw the distinctive 2×2 tracks from a larger member of the weasel family, either marten or fisher. In the 2021-2022 winter, we saw these tracks a couple more times. So, roughly speaking, we saw these tracks three times in 19 years. This year there has been an explosion in the number of these tracks. In a short couple miles of skiing, we typically see at least one set and commonly cross several sets just one day after a storm. Sometimes you can see where the marten drags its body through the snow, probably for the purpose of scent marking rather than just for locomotion and fun as otters (and ravens) do.

Since martens are fiercely territorial and will cover several miles each night criss-crossing their territory to hunt and fend off any interlopers, all these tracks are probably from a small number of animals. The size of an American marten’s range in the Sierra Nevada runs from as little as 0.7km² to just over 7km² (0.7-5.8km² for females, 1.7-7.3km² for males), depending on food availability. Roughly speaking, that means the range would be 1-3km across in general. Given the abundance of one of the marten’s favorite foods (squirrels) in these particular woods, the typical range is probably more in the middle of that range than at the high end, so say about a mile across, maybe less. But this year we have been seeing these tracks across an area that is several miles long. So it seems like our ski touring spots are home to a successful breeding couple. That’s fun if you’re a tracker, but less fun if you’re a squirrel!

Tom has actually seen a Pacific fisher a couple miles from this area and there are other verified sightings not too far away. So it is possible that these are fisher tracks, but martens are far more common, so it’s most likely these are marten tracks.

In most of the conditions we see these, it is impossible to tell them apart. To tell a marten from a fisher reliably, you need a very clear track and precise measurements. The size of their tracks overlaps and so does the distance between them (i.e. the length of their gait). In general, though, fishers have more “loading” on their feet. The feet are slightly bigger, but the animal is much heavier, so they tend to sink deeper. So even though the fisher is bigger, in deep snow, the fisher takes shorter steps and leaves a “ploppier” track. Based on that and the overall prevalence difference, we figure that we’re seeing the somewhat common Pacific marten rather than the rare Pacific fisher.

We also this year came across tracks that at first looked like just more squirrel tracks, which were abundant in the forest we were in. In the soft snow, the individual tracks were not clear, so you couldn’t see the shape of the feet or even the pattern they were landing in, but there were several indicators they did not belong to squirrels.

First, when they passed a tree, they did not take the classic squirrel strategy of climbing a short ways up and jumping off.

Second, they made long forays out into large open areas. Squirrels will venture into the open, but usually only for a short distance or when making a bee-line from tree to tree.

And finally, there were thin imprints of the tail. Squirrels generally leave no tail imprint, but if they do, it would be the bushy tail of the gray squirrel or the less bushy, but not yet thin, tail of the chickaree. With a few other clues, we decided we were most likely looking at the trail of a long-tailed weasel.

The video below was taken by our friend Rachel while hiking with us on Mount Hoffmann in July, 2020. I believe this is the closely-related short-tailed weasel, whose tail is generally one-third of body length or less while the long-tailed weasel tail is usually half as long as the body or more. That said, biologists studying the distribution of the two species in Connecticut found that sometimes they needed to do DNA testing in order to make positive IDs, as they species overlap in size and many other characteristics.

We’re not entirely sure of this ID, but it seems likely to be one of the weasels, either short-tailed or long-tailed, and given that the latter is more common and given the tail-drag marks, we’re guessing that it is a long-tailed weasel. But in snow this soft, there was very little detail in the tracks, so this is just a guess.

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Coyotes

Finally, Tom’s favorite animal to track is the coyote. He has tracked them for several miles, sometimes more than five. They will often stick to a line like they are following a compass heading. And they move fast. We know this because sometimes we see their tracks on the Badger Pass Road soon after the plow has passed or on the Glacier Point Road soon after the cross-country groomer has passed. Since we have a rough idea of when the plow passed and when we passed, we can ascertain that the coyote is on a mission, trotting along no slower than 6mph and probably faster. Tom’s theory is that the coyote is moving fast on a line through relatively open areas in hopes that one of the smaller critters with shorter legs will be struggling through the snow and the coyote can surprise it, overtake it, and get a meal.

We recently (Feb 2023) saw some confounding tracks. From a distance, it looked like the 2×2 lope of a marten, but the size was too big. Upon closer inspection, we saw it was a coyote. Commonly in the snow, coyotes “direct register,” meaning that the hind foot lands in the spot just vacated by the forefoot on the same side. This increases their efficiency while moving through snow.

That’s one of the ways you can tell a coyote track from a domestic dog’s track. Domestic dogs, well-fed and comparatively uncoordinated, don’t need such efficiencies so are rarely precise in their registering, if they register at all. They also tend to have meandering tracks as they are excited to be outdoors and have no fears of wasting energy. Finally, their feet also tend to splay more because they simply have less-strong feet because they don’t spend all day everyday trotting along like coyotes.

So this track, which we followed for a couple of miles on Glacier Point Road was a bit perplexing. But we realized that the foot that failed to direct register was always the left hind foot. And the coyote would occasionally rest and then we would see it direct register and slowly get sloppier until it rested again. We also saw a place where it left the road and there was blood in the snow. At first we thought it was from a kill, but there were no signs of other tracks or fur or anything.

We finally guessed that the poor coyote had injured its foot and had minor bleeding, possibly from something as simple as snow building up and turning to ice that eventually irritated the foot. It also seemed at times to want to leave the road, but this was after a big storm. It would make a brief foray into the soft snow off the groomed cross-country ski trail and then return to the firmly packed road until, finally, it took a right turn and went off into the woods near Bridalveil Creek campground.

Much of that is just guessing, but it is fun to play detective while following an animal through the woods or, in this case, down the ski trail.

Did we correctly piece together the story of this coyote? We’ll never know, but the simple act of trying can deepen your experience of the land you move through and live in.

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A Few More for Fun

Here are a couple more for fun. First a deer track. Deer seem to be rather inefficient walkers in the snow, dragging their feet and sinking deep on their small hooves. But as a general rule, they try to move lower for the winter and they often move in groups, which helps as they can take turns breaking trail. With the huge snows we’ve had this year, a lot of the animals seem exhausted. The deer in the video was alone, at relatively high altitude (about 5500 feet) and seemed very tired. When we drove home, she was lying in the road. It was sad knowing that two more feet of snow were forecast for the next day.

The group of deer in the were lower and and had packed out trails around the river near Wawona and were doing much better.

At the other end of the size spectrum are the mice and voles. We don’t even try to identify species, but it’s impressive to see the distances they cover, almost floating on the snow with their delicate tracks. Mice leave tracks similar to mini-squirrels, often with a tail drag. Voles do not typically drag the tail and are often in a 2×2 pattern. So if there is a tail drag, it’s probably a mouse. If there isn’t a tail track it could be either one.

That said, the deer mouse is more likely to be out in the snow while the vole is more likely to stay snug in the subnivean layer. The last tracks in this gallery are funny ones: the little rodent was going along just fine until it came to a dropoff about a foot high left by the cross-country grooming machine. The critter just walked off the cliff, leaving a big (or little actually) plop in the snow.

The first two sets of tracks pictured below just impress us for how far these tiny guys were willing to walk in the open on the snow with the potential for getting intercepted by a hawk or a bobcat. And where was he or she going? Why walk all the way to the tree just to walk back? Who knows?

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Final Thoughts

Even though the forests can feel quiet in the winter, paying attention to the tracks brings them alive. Even more than in the summer, you can get a sense of who frequents these woods and what the rough proportions are between, say, squirrels and coyotes and fishers. If you live near a place that has undisturbed snow, a tracking outing is a great way to get to know the habitat.

Recommended Books

You can, of course just go out on your own, but having a decent tracking book can help get you started.

For our area, we really like Mark Elbroch, Michael Kresky and Jonah Evans, Field Guide to Animal Tracks and Scat of California (University of California Press: Berkeley, Los Angeles, London, 2012).

The Stokes guide is also quite good, but oriented more toward the East Coast. See Donald and Lillian Stokes, A Guide to Animal Tracking and Behavior (Little, Brown and Company: Boston, Toronto and London, 1986).

For a more compact option for the Sierra Nevada, the wonderful Laws Field Guide to the Sierra Nevada by John Muir Laws (Heyday Press, 2007) has some minimal information on tracks and scat.

Spring visitors to Yosemite, looking around and seeing only deer with no antlers, sometimes ask rangers, “Where are all the bucks?”

People more familiar with deer will know that bucks lose their antlers in late winter and regrow them over the course of the spring and summer. So when you see a deer in March, whether male or female, you won’t see those characteristic antlers.

Pause for just a second to think about how amazing it is that these animals regrow and then shed their antlers every year. Deer antlers are unlike anything else in the mammal world. They are among the fastest growing tissue in the entire animal kingdom. They are not just majestic, but also fascinating to medical science and to casual observers like us! 

And that’s just the beginning. Did you know scientists can get mice to grow antlers? Do you know about the unique antlers of Yosemite’s most famous deer ever? Did you know that some Asian deer don’t have antlers at all, but something much scarier?

Look at these two guys below who stopped by the house on April 26 with just their short spring antlers. We don’t know at this point how large these antlers will get.

A healthy, mature male with excellent nutrition will grow these out to a majestic “rack” with over three feet of “spread” by September. Mule deer average about a quarter to a half inch per day of antler growth throughout spring and summer.

Other members of the deer family (Cervidae) are even more impressive. In a single day, elk can grow an inch of antler and moose can add a full pound. Still, this is nothing compared to the extinct Irish Elk (actually a deer, not an elk). It could grow and regrow antlers up to twelve feet (3.5m) across.

Just how do they do that?

That’s just what scientists trying to understand bone growth, regeneration, and other basic science questions want to know.

Wait, Antlers are Bones?

Yes! Antlers are bones. People sometimes confuse antlers with horns, but they are very different. Horns are mostly keratin, the protein that makes up hair, claws, hooves, feathers and, yes, horns. Horns are found on both males and females, grow continuously, are permanent, hollow, and grow from the base. They are found in cattle, bison, buffalo, sheep and several other mammal families.

Antlers are altogether different. Antlers are unique to deer and only found among males except in reindeer, including caribou. Most uniquely, though, they are shed and regrown every year.

That requires a significant outlay of energy and nutrients for the male deer. Just like other bones of the body, the thickest part of the antlers have a spongy interior that contains bone marrow, which is where the body makes blood cells. In other words, the antlers are full-fledged bones that do all the things bones do.

During the growing phase they are soft and made up mostly of water and protein. They are covered with “velvet” that is rich in nerves and blood vessels. As summer ends, antlers stop growing, mineralize and harden in time for “rutting” season when the bucks use their antlers to compete in pushing contests. The winner is the one who gets to mate.

Wondrous Velvet

The fuzzy velvet that covers a deer’s antlers during the growth phase is how all the nutrients get to those growing bones. Because these growing antlers are mostly water and protein, they are relatively fragile.

So in addition to having a rich blood supply, the velvet is full of nerves and highly sensitive. In fact, it’s so sensitive that deer can be seen gingerly avoiding branches and brush in order to avoid injuring the velvet. This helps ensure they get a nice, symmetrical rack to increase their chances of mating in the fall.

We might think that antlers are a formidable weapon for defense, but that’s only true once they harden and shed their velvet. Their main purpose is to challenge other bucks during the rut and to display dominance, not to fight off coyotes. If a buck in the velvet phase is forced to fight off a predator, he will actually fight with his hooves and protect those antlers from damage. They are too precious to risk in a fight, and too soft and too sensitive to be effective anyway.

It is only late in the season, when the antlers are fully formed and hardened and ready for contests with other bucks that the velvet dies and falls off. And what does a deer do with that discarded velvet? It eats it. Can’t let all that good protein go to waste!

The Life Cycle of a Yosemite Deer’s Antlers

Of course, this cycle is more or less the same everywhere, though the timing might differ a bit here and there due to climate.

• March. Bucks shed antlers as early as January, but rarely. Shedding is most common in March.
• April. New growth starts 2-4 weeks after shedding.
• July. First forking of antlers is achieved. Before this, all bucks will have just a single spike. Once they reach full size, they will begin to harden and mineralize.
• September. Antlers have grown to full size and strength. At this point the velvet dies and bucks then start “horning” brush and trees to scrape it off.
• October or November. Necks swell to prepare for rutting contests.
• November to January. Rutting Season. Mostly a pushing contest where the goal is to drive the rival to his knees. Once achieved, the dominant male “runs” a female for several days until she lets him mate with her. Once that’s done, he starts running another female. This lasts into January, sometimes into February.
• Once the mating season is over, the bucks shed their antlers and the cycle starts all over again.

Notice in the photos below how the bucks sparring in the top photo from September still have thin necks. In the second photo, where they are in it for real, the necks have thickened and are ready for the real contest.

Where Do All the Antlers Go?

The deer population of Yosemite probably numbers in the thousands. If only a thousand bucks are shedding 2,000 antlers every year, where do they all go? You would think that 2,000 antlers shed year after year would start to become a bit of nuisance. Why don’t we see them all the time on hikes?

There are a few reasons. The first is that the deer don’t follow our trails, so a lot of the antlers end up in places humans don’t frequent. In addition, the deer often go to lower altitude to shed antlers. Still we see deer tracks in our area all winter, so they must be shedding antlers in our area.

So after many years, shouldn’t there be antlers everywhere?

Mature, hardened antlers are about 40% protein and 60% minerals. That makes them a great nutritional supplement for squirrels and other rodents who do not have subscriptions to Amazon Prime and can’t get their calcium supplements delivered by UPS. Also, rodents need to gnaw in order to maintain their teeth. When they find an antler, they gnaw on it. Porcupines are particular fans of deer antler, but in our area they only inhabit the lower reaches of the deer’s range. That leaves squirrels as the great recyclers of all that calcium, phosphorous and protein tied up in deer antlers. And thanks to them, the woods are not littered with years of antler accumulation.

What would happen if there were no squirrels? It turns out that we know the answer. The squirrel population of California generally and Yosemite in particular was devastated by disease in the early 1920s. For years at a time into the 1930s, as few as a single pair of squirrels were seen in Yosemite Valley. The grey squirrel almost went extinct in much of California. In 1925, a few years after the collapse of the squirrel population, park naturalist Carl Russell went walking an area where deer were known shed antlers. He found more than two dozen single antlers in less than a mile without leaving the trail. Without the squirrel helpers to break down the antlers, they apparently did start to accumulate in the 1920s.

Antlers and Medical Science

Antlers are the only appendage that any mammal regenerates. They also grow faster than almost any tissue in the animal kingdom and are probably the fastest growing bone in the world. You can see why scientists are interested in antlers. If we understood antlers better, we might conceivably be able to regenerate a lost finger, heal broken bones faster or prevent and reverse osteoporosis.

Scientists have long known that there was something special about the cells at the base of the antler, the pedicle, from which the antler regrows every year. In the 1960s, researchers transplanted pedicle cells to the leg of a deer and it started to grow an antler on the leg! Even more surprising, they have transplanted pedicle cells to the forehead of a mouse and guess what? The result is this somewhat disturbing picture of a mouse with a sort of unicorn in its head. Do not try this at home!

More recently, scientists have discovered the key genes that allow the deer to grow bone so quickly. In 2018, researchers at Stanford identified one gene that promotes the exceptionally rapid growth of antlers and another that promotes the exceptionally rapid hardening of antlers. Both of these genes are present in humans and linked to bone development. Understanding them better could lead to therapies for osteoporosis and other bone diseases.

And that’s not all. There could even be implications for cancer research. Why can’t other mammals regenerate appendages? Nobody knows for sure, but deer commonly suffer from deformities or uncontrolled growth of their antlers. It appears there might be some sort of tradeoff. You can have rapid growth and regeneration, but it might come at the cost of being more susceptible to that other form of rapid growth, cancer. So the study of deer antlers might have clues to what causes runaway cell growth and how to control it.

More Fun Facts About Antlers

• If a deer is injured in the right front leg while the antlers are growing, the right antler will be deformed or stunted. But if the deer is injured in the right hind leg, the left antler will be deformed or stunted.
• Mule deer antlers can weigh over 30 pounds, much of which is calcium.
• To get all the calcium they need for their antlers, deer take it from their own bones, by preference non-weight-bearing bones like ribs. This means they get temporary osteoporosis every year.
• Antlers have been important to humans for thousands of years – they are one of the primary tools used for flintknapping, that is making arrowheads, spearheads and the like from flint and obsidian.
• The number of points on an antler do not indicate the age of the deer. In general, antlers get larger with age up until about 5.5 years old (the buck’s sixth summer) then stabilize. As a deer ages they can get smaller each year.
• Age is only one determinant of antler size. The other big one is nutrition. Calcium is important, but during the growth phase antlers are mostly protein, so protein availability really affects antler size.

And the Really Crazy Stuff

If you’ve made it this far, now we get to the really crazy stuff! Here’s a quick bit about Yosemite’s most famous deer and deer species that don’t grown antlers at all, but something much scarier looking.

Yosemite’s “Rhino Buck”

Unquestionably, the most famous deer in the history of Yosemite was an ancient old buck people called Old Horny. He got his name because he had a third antler growing out of his forehead. Three-antlered deer are rare, but not unheard of. Typically, however, the third antler grows out of the frontal bone like the other two. Old Horny is believed to be unique in that his third antler grew out of the nasal bone.

He was much beloved by visitors in the 1920s who frequently fed him buttered toast, back when feeding the animals was a standard part of a national park visit (please don’t revive that tradition!). When he finally died, it was discovered that he was exceptionally old. His teeth had been ground all the way down to the gums, a sign of extreme old age in a deer.

That’s not a surprise — antler deformities are more common as deer age and Old Horny’s twisted antlers were another testament to his advanced age.

Saber-toothed Deer?

What could be stranger than a three-antlered deer? How about a saber-toothed deer! If you live in parts of Asia where the water deer come from, or in the UK where they are considered invasive, you might know about deer with tusks. For most of us in North America, though, the thought of innocent little Bambi with deadly tusks is a bit unsettling.

How in the world do you end up with a saber-toothed deer? There are in fact several species with tusks. It turns out, that antler size correlates to the size of the animal and, below a certain size, antlers are just not effective fighting tools. All the deer with tusks are under 15kg.

They also live in dense forests or jungle and are solitary rather than herd animals. This is important because antlers allow for bloodless competition among bucks. Herd animals do not want to shed blood, because they do not want to draw predators to the herd. Also, deer with antlers tend to live in open areas where they can display their large antlers from a distance as a dominance display. In tight vegetation, there’s no advantage to a big rack visible across distance and it just gets hung up in the vegetation. So these small, solitary jungle dwellers have tusks.

It turns out that ancient deer may have had both tusks and antlers, but as they evolved, one came to dominate based on the size, habitat and social life of the deer. However, even our nice Bambi mule deer have to potential to grow tusks. On occasion, hunters who kill a mule deer find that in fact it has canines up to an inch long. In other words, the basic genetics for tusks remains latent, it just is not expressed since antlers are so much more useful in the places mule deer live, like Yosemite.

All of that is somewhat theoretical, but it’s the best guess of the scientists who published the wonderfully-named most recent research article on this: “Stabbing Slinkers: Tusk Evolution Among Artiodactyls,” by Doreen Cabrera and Theodore Stankowich in Journal of Mammalian Evolution, Vol. 27, Iss. 2,  (Jun 2020): 265-272.

Wrap Up: Your Turn.

I hope all that deepens your knowledge of our deer, and yours too if you have them near your home. I also hope that the images of the “stabbing slinkers” will not trouble your dreams!

There’s a lot more one could say about antlers, but maybe we already said too much. Our goal with these articles is to expand people’s knowledge and appreciation of the natural world around them. We find these explorations interesting, but maybe you would rather read about different things. If you have ideas for things related to Yosemite nature or history that you would like to read about, let us know by email or in the comments. We would love to read your suggestions!

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Read More

There are countless articles about antlers on everything from the Smithsonian website to hunting blogs. A lot of state departments of wildlife have nice pages too. These are some fun articles as well as some of the more esoteric, academic sources that played into this article.

Fun and not too scholarly:

• What are antlers and why do deer have them? at Wildlife Online. This is a great, detailed, non-scholarly overview with some excellent photos, including photos of sectioned antlers, infrared photos of deer during the antler growth phase and after and lots of interesting stuff.
• Jason Bittel, “Antlers Are Miraculous Face Organs That Could Benefit Human Health.” Smithsonian Magazine, June 12, 2017.
• Richard Grant, “Biggest. Antlers. Ever. Meet the Irish Elk.” Smithsonian Magazine, June 2021.
• Outside/In podcast episode: Holy Scat! Why Antlers Are Freaking Amazing, March 10, 2022.
• Robert A. Pierce II, Jason Sumners, Emily Flinn, “Antler Development in White-tailed Deer: Implications for Management White-tailed deer management.” A nice guide focused on white-tailed deer developed jointly by Missouri University Extension and the Missouri Department of Conservation.
• Similar to the Missouri page, this is nice set of resource pages mostly on white-tailed deer by the Mississippi State University Deer Ecology & Management Lab.

A bit on the more esoteric side:

• Price JS, Allen S, Faucheux C, Althnaian T, Mount JG. “Deer antlers: a zoological curiosity or the key to understanding organ regeneration in mammals?” J Anat. 2005;207(5):603-618.
• Doreen Cabrera and Theodore Stankowich. “Stabbing Slinkers: Tusk Evolution Among Artiodactyls.” Journal of Mammalian Evolution, Vol. 27, Iss. 2,  (Jun 2020): 265-272.
• G. A. Lincoln, “Biology of antlers.” Journal of Zoology (1992) v. 226, pp. 517-528.
• Chunyi Li, John Harris, James Suttie. “Tissue Interactions and Antlerogenesis: New Findings Revealed by a Xenograft Approach.” Journal of Experimental Zoology, v. 290, pp. 18–30 (2001).
• Hanae Armitage, “Genes behind rapid deer antler growth, hardening identified.” Stanford Medicine News Center, October 30, 2018.
• Science Direct AI-generated selection of articles on antler-research (many of which require institutional affiliation to read)

Coming to Yosemite to watch flowers open may sound like the beginning of a joke — Did you hear the one about the guy who went to Yosemite to watch the flowers open?

And yet, when the deer are kind to us, watching the evening primroses open in our yard is one of our great pleasures of summer. The nightly show is so stunning that it was once one of the principal attractions of Yosemite, rivaling Half Dome and the giant sequoias with visitors in the early 1900s. And then, just as Yosemite became world-famous for those blooms, they were gone forever. The story of the evening primrose and how they mostly disappeared touches on a surprising range of topics from the history of the Ahwahneechee, their expulsion from Yosemite, the commercialization of the park, the history of color and motion picture photography, and ultimately humans’ relationship to nature. That’s a lot for one little flower.

Read on to learn about evening primroses.

• Part I: The Natural History of the Evening Primrose
  • Why is watching a flower exciting?
  • A bit about their ecology
• Part II: Cultural History: The Rise and Fall of Evening Primroses in Yosemite
  • How they came to be a major attraction in Yosemite around 1900
  • How they came to disappear
  • What the story of the evening primrose says about the human presence in Yosemite and our relationship with nature

Part II really gets down in the weeds (bad pun, I know), but if that does not interest you, you can just look at the pictures and videos. Do not skip the video.

What’s so exciting about watching a flower blossom?

In the case of Oenothera elata, aka Hooker’s evening primrose, the yellow blossom almost the size of the palm of your hand opens most of the way in just a few seconds. When people see video of an evening primrose opening, they usually think it’s a time-lapse. On the best nights at our house, it happens over 100 times in about 40 minutes.

A few years ago, our friend Russ of Yosemite Hikes fame took this one-minute video in our yard. It will give you a sense of how fast the evening primrose opens. This real time, not a time lapse:

This shorter video is a time-lapse that shows a five blossoms opening in 15 minutes and 17 seconds, compressed into about 12 seconds.

Basic Evening Primrose Ecology

The evening primrose is a biennial. The first year it grows with just a basal cluster of leaves — no stalk and no flowers. It’s just putting out leaves and captures as much solar energy as it can, storing that energy in its roots for the big show the next year.

That second summer, it uses the stored energy and the new energy coming in to grow as high as four feet tall. Each plant can have a few dozen blossoms, with just a few opening each evening at sunset over the course of about a month. The blossoms last for only one night.

Why wait until sunset to open? Because the plant doesn’t want it’s precious pollen and nectar taken by day-flying pollen thieves (no judgement, this is just what botanists call an insect that takes pollen and nectar without pollinating the flower). To be effective gathering and spreading the gooey, filamentous pollen strands of an evening primrose, the insect needs to be properly equipped. No insect is so well-equipped for the task as the sphinx moth, who we will meet in a moment.

These blossoms really are intended for the night flyers first and foremost — in the full heat of the summer, the blossoms will be wilted and “dead” by 11am, sometimes earlier.

The pistil, that long thread with the cross at the end (called the stigma) in the middle of the blossom, is the pollen receiver. If you pull it out, the filament is 2-3 inches long. Around it are the stamens with a sort of gooey pollen that sticks to the moths and travels with them to the next blossom. The pollen grain brushes off on the cross-shaped stigma, then travels all the way down that tube to the ovaries to fertilize the seeds. It has to complete that journey overnight before the flower wilts.

The plant then makes hundreds of seeds for every seed pod. The pods eventually dry out and open and that tall plant, blowing back and forth in the wind, ejects the seeds a fair distance, like Father O’Connor spraying the congregation with holy water.

More on the evening primrose

• Calflora database for information on distribution and such
• USDA distribution map
• Calphoto for lots of photos

Is that a bird?

Notice the supporting cast in that video. It looks almost like a hummingbird when you first see it flying, but you will soon see that it is the gorgeous White-lined Sphinx Moth (Hyles lineata).

The sphinx moth’s secret weapon is a very long proboscis that lets it reach deep into flowers that have a large nectar reward. They are known to frequent columbines and we have seen them on pennyroyal, but the evening primrose is clearly a favorite. The sphinx moth is a major evening primrose pollinator. In return, the evening primrose provides food not just for the adults who come for the nectar, but for the caterpillars as well.

Their timing is impressive. We rarely see these moths, but within minutes of the first blossom opening, they arrive. To our human noses, the smell of the evening primroses is subtle, not like the powerfully-scented flowers like azalea or pennyroyal. Apparently for a sphinx moth, it’s like Mama Ciccardi’s famous marinara sauce cooking on the stove on a summer evening — within minutes, the smell wafting from the flowers calls them to dinner from the far corners of the neighborhood.

Other pollinators

The sphinx moth is not the only pollinator. We see other insects in the flowers sometimes, but typically only in the morning. Carpenter bees (specifically Xylocopa tabaniformis) can be a major pollinator. The overlap in the range between the Xylocopa tabaniformis and the Oenothera elata suggests this is an ancient relationship developed through long co-evolution (Barthell and Knops). In our experience, though, it is the sphinx moth who rules the skies over and around the evening primroses when they open.

When does this happen?

In drought years and wet years, hot years and cool years, the first blossoms are always within a couple of days of Theresa’s birthday at the end of June (The exception to this rule is this record-breaking snow year of 2022-2023 when as of July 3, there are still no seed pods showing). The show reaches its peak in early July and goes strong through most of the month and fades by early August, after which it’s just a few blossoms here and there. We’ll still get the occasional blossom into October, sometimes on plants that appear all but dead.

Where does this happen?

The evening primrose is not a rare plant, but it is a favorite food for deer. So while widespread, there are typically only a handful in Yosemite Valley that blossom each year. A century ago, that number was in the thousands, perhaps tens of thousands or even more, but those days are gone (that’s the story of Part II). To the best of our knowledge, the best places to see them are just east of Tioga Pass along Highway 120 (a terrific display there in good years) and at our house, except in those years like 2021 when the deer ravage “our” plants (they aren’t our plants of course, any more than we are their humans).

Taxonomy: a primrose by any other name

The evening primrose is not closely related to the primrose, just like the primrose is not closely related to the rose. They are three distinct flower families belonging to three separate orders. Roughly speaking, that means they share a great-grandparent. The evening primrose is actually somewhat more closely related to the rose than to the primrose. To get technical, roses (Rosaceae family) and evening primroses (Onagraceae family) both belong to the Rosids clade, while primroses (Primula family) belong to the Asterids clade.

Part II: The rise and fall of Yosemite Valley’s flowers

Today’s visitor often comes to Yosemite in hopes of seeing a bear, but very few people make the trip to Yosemite in hopes of seeing a flower open at sundown. In the early 1900s, it was the reverse. There were no bears in Yosemite Valley. When a bear did enter the Valley, most people thought it should be chased off or killed as soon as possible.

Meanwhile, they ranked wildflowers up there with El Capitan and Yosemite Falls as a must-see attraction. The wildflowers of Yosemite Valley inspired some of the earliest color photographs and the world’s first time-lapse movies of flowers. Indeed, time-lapse photography was virtually invented in Yosemite by Arthur Pillsbury, who held a photographic concession in the park from 1906 to 1922.

Among all the flowers of the park, the evening primrose was one of Pillsbury’s favorites. When he first came to Yosemite, he found entire meadows that would turn yellow as the flowers opened en masse. Our small patch on its best days sees 140 blossoms open in 40 minutes, peaking at perhaps 7-10 blossoms per minute. How big were the massive displays of Yosemite Valley, reputed to have turned entire meadows yellow? One hundred blossoms in the peak minute? Five hundred? Probably thousands at the peak.

Wildflower Tourism at the Turn of the Twentieth Century

Wildflowers were such an integral part of the Yosemite experience that when the National Geographic Society ran an article about the park in their weekly Geographic News Bulletin (vol. 1, n. 9; 3 April 1922), they titled it, “The Park of a Thousand Flowers — Yosemite,” and noted that “Yosemite National Park is beloved especially by children because of its many flowers.”

It seems strange, in our era of video games and Red Bull athletes to think that children were drawn to Yosemite for the flowers, but apparently it was so which speaks to a different aesthetic in 1922 than in 2022.

That publication was aimed at teachers and clearly some read it. Later that year, The Western Journal of Education (vol. 82, no. 7, p. 8-9) ran an article on “Yosemite National Park for the Educators” that described Yosemite Valley in these terms, highlighting the central importance of the evening primroses (my emphasis):

Decorate these walls with titanic structures — El Capitan, Half Dome, Sentinel Rock, Cathedral Spires, Cathedral Rocks — chiseled smooth as glass in many places, then stud these walls with foaming cataracts that flash in the sun, Yosemite Falls… Bridal Veil…. Carpet the meadows with Mariposa lilies and evening primroses and other blossoms which have made Yosemite known as the “Park of a Thousand Flowers.” This is Yosemite Valley.

Western Journal of Education, 1922

In short, for the visitor of 1922, the flowers of Yosemite Valley rivaled El Capitan and Yosemite Falls in majesty in a way that is rarely the case a century later.

The Decline of the Evening Primrose

And yet, by the time these publications came out in 1922, the golden age of the Yosemite Valley flowers was over. In the Handbook of Yosemite National Park from 1921, the great botanist Willis Jepson wrote regarding the evening primroses (my emphasis):

One of the remarkable sights of the upper reaches of the Valley in midsummer are the fields of tall yellow Evening Primroses… In favorable seasons the dry open fields about Yosemite are often yellow with these stately plants. Many of the finest groups, however, are now a thing of the past, due to the mowing of the meadows for wild hay.

Jepson, Handbook, p. 254

In her 1929 survey of flowers in Yosemite Valley, the naturalist Enid Michael noted that, “June of the year 1920 witnessed the last great bloom on the floor of the Valley” (Giddens and Heady, p. 25). Joseph Dixon, writing in 1934, said that in a survey of Yosemite Valley in the late 1920s, only six evening primrose plants had been found in the whole valley (Dixon, p. ?? [get page no. from copy in Yosemite Research Library]).

A few years later, the Wildflower Man of Yosemite himself, photographer Arthur Pillsbury, wrote (my emphasis):

Unhappily this Primrose is now almost extinct in the Yosemite meadows. The mowing machine took its toll and since it has been put on the protected list the deer have acquired a fondness for the leaves, not hesitating, either, at blossoms.

Pillsbury, Picturing, p. 54

What was still a highlight of a Yosemite trip in 1910 had all but disappeared by the 1920s. The naturalists lamenting the loss of the evening primroses typically point to two factors: farming and deer.

Why did deer become a problem for Yosemite flowers in the 1920s? What changed? Why were there so many flowers in 1910 and why were they all but gone by 1922?

Flowers in the Valley before 1900

After the glaciers receded, Yosemite Valley was a wetland or a lake. As the lands silted up and the waters receded, there is some evidence of ancient forest in Yosemite that was wiped by either rock slides or fires, either natural or manmade (Gibbens and Heady, p. 8-9).

For at least a few thousand years, inhabitants of Yosemite Valley set fire to the meadows annually, typically in the autumn. This made it easier to harvest fallen acorns and promoted the growth of plants with edible bulbs and tubers. Many of the common flowers we know today were prized as root crops, like Elegant Brodiaea (Brodiaea elegans), Blue Dicks (Dichelostemma capitatum), Mariposa Lilies (various Calochortus species), and many more. See the wonderful article by M. Kat Anderson and Frank K. Lake on the various “geophytes” (roughly speaking, “root crops”) prized and eaten traditionally in California.

The meadows were also important for plants such as dogbane (Apocynum cannabinum). Dogbane was not an important food crop. As the name suggests, it’s poisonous at least to dogs. It was essential for making twine which could be used to make baskets, nets, traps and anything else requiring rope. It was therefore an essential material for the residents of Yosemite Valley.

The Valley was sometimes described as “swampy,” but the new guardians of the Valley brought changes. It’s likely that swampy crops like onion were common, though they are rare today in Yosemite Valley. Meanwhile, those same moisture levels made the meadows inhospitable to the native pines, firs and oaks. The Ahwahneechee practice of burning the meadows also kept tree encroachment at bay.

It appears that the Ahwahneechee used fire to hunt the deer in Yosemite Valley, and probably elsewhere (Ernst, p. 39). So the fire that kept the trees from overtaking the Valley also indirectly helped keep the deer population down and, therefore, prevented the deer from eating so many of the Valley’s flowers. Oral tales speak of the Ahwahneechee going up to the Valley rim to hunt for deer, presumably because deer were not sufficiently abundant on the Valley floor.

As soon as the burning stopped, the size the of the meadows started to decrease. The European-American methods of controlling the brush through cutting was far more labor intensive and far less effective than burning. It was impossible to keep the overgrowth at bay and the meadows began to fill with brush and forest. A survey in 1868 found that there were 745 acres of meadow in Yosemite Valley. By 1937, only 327 acres of meadow remained (Gibbens and Heady, p. 24).

In addition, the European-Americans changed the hydrology of the Valley. Blasting the recessional moraine near El Capitan in 1878 for the express purpose of draining the Valley had a major impact on the meadows. Raised roadbeds disrupted the flow of water. Utility pipes often cracked and were abandoned, leaving them to take in water and channel it out of the meadows (Gibbens and Heady, p. 8 and passim). With the drying came more brush, more trees, and fewer flowers.

All of these changes that came with the expulsion of the Ahwahneechee combined to create a Valley floor that had far less meadow and much more undergrowth than it had had in perhaps thousands of years. Still, the 1937 state of the Valley was far less forested than what we have become accustomed to in the twenty-first century. The result was undoubtedly a greater quantity of flowers than we know today, but beyond that we mostly know only about the species that were used for food, and precious little even about those.

Yosemite Valley from Invasion to National Park

After the Ahwahneechee attacked a couple of trading posts, the Mariposa Battalion invaded Yosemite Valley in 1851 and forced the Ahwahneechee out for the first time. The tribe returned that winter, but most were forced out definitively in 1852. Though a small number resided in the Valley into the 1960s, they effectively lost control of their lands and therefore the meadow burning stopped in the 1850s and the meadow drying began soon after, with the consequences we’ve just seen.

Those consequences did not, of course, happen immediately. In 1855, just four years after the initial invasion by the Mariposa Battalion, an early tourist wrote that Valley was rich with strawberries:

The wag of our party said that any man who would find three feet square in a space of six hundred acres, where we encamped, that did not have the strawberry on it, should have the pleasure of shooting through his hat. The search was made for the space; but our friend says his hat will never have a hole through it from this proposition.

Reprinted in Browing, p. 219.

In 1864, Yosemite Valley became a California state park, but it was managed much less actively than today. Despite its status as a park, settlers and business people soon began grazing cattle and horses and plowing for crops. At least 20 acres of El Capitan meadow were plowed and sown with fodder for horses and cattle. Many other meadows were plowed or used as pasture for both horses and cattle. By 1887, 150 acres of Stoneman Meadow was under active cultivation. People began to complain and in 1890 new rules were passed to reduce farming in Yosemite Valley. Nevertheless, the government plowed and planted Ahwahnee Meadow from 1910 to 1914. Other meadows were not plowed, but they were mowed for “wild hay” as late as 1924 (Gibbens and Heady, pp. 4, 21-22).

Despite this history of plowing and mowing, Yosemite Valley nevertheless had breathtaking displays of flowers, with the evening primrose as one of the stars, perhaps the star of the show. How is it, then, that the evening primroses thrived in the presence of mowing, and yet disappeared about the time mowing stopped?

Naturalists of the time point to two factors. First, before the mowing ended, it moved to new locations and wiped out some of the best surviving collections of flowers. Second, the deer population boomed. By the time the plowing and mowing stopped, the number of deer was sufficient, as it is now, to all but eliminate the evening primrose from the valley.

Yosemite Valley: Death Trap to Animals
(Or: Why the Deer Didn’t Eat All the Flowers in 1900)

We think of deer as numerous and ubiquitous in Yosemite Valley, but it wasn’t always the case. As we saw in the discussion of Ahwahneechee practices, deer had probably been rare on the Valley floor for hundreds, perhaps thousands of years. With the influx of settlers and their guns in substantial numbers, deer along with most large animals, were hunted to extinction on the Valley floor.

Though the national park had been created in 1890, Yosemite Valley remained a state park under state management. Rules against hunting were widely ignored. In 1905, Yosemite Valley became part of Yosemite National Park. The next year, the U.S. Army, who managed the larger national park, took over management of Yosemite Valley as well. In his 1906 report, Acting Superintendent Major Harry Benson reported to Washington about the conditions he found on taking charge of the Valley (my emphasis):

The Yosemite Valley itself has, during recent years, been a death trap to all game that was unfortunate enough to enter it. Practically every person living in the valley kept a rifle, shotgun, and revolver, and any animal or bird that was unfortunate enough to enter the valley was immediately pursued by the entire contingent, and either captured or killed. A bear pen constructed about three years ago was found by me within 400 yards of the Sentinel Hotel.

During the early part of September two bears entered the valley, causing great consternation among those people who had been living here for some time, and they all seemed to think that these bears should at once be pursued and driven out.

Benson, Report, p. 10.

To make matters worse, during those years, the army only managed the park from May through October. The rest of the year, only two rangers oversaw the entire park. Benson noted that, as the two rangers did little patrolling, “the game scarcely receives any protection from them.”

Those conditions were terrible for the deer, but marvelous for flowers. The valley floor was reputed to be white with camas lily in the early season and yellow with evening primrose in July. It was during this period that Arthur Pillsbury took his famous hand-tinted photos of evening primroses and, later, his time-lapse movies of them opening.

As late as 1908, Acting Superintendent Benson was still worried about the low deer population and intensive hunting. But from 1909 on, the annual reports of the Acting Superintendents repeated every year that the deer population was increasing. This hurt, above all, the evening primroses. As we have found in our yard, the deer seem to love this plant as much as we do. Of course, the process took time. In his 1910 book, The Yosemite Valley, Galen Clark still noted that the evening primrose was “very common in Yosemite.”

After about 1910, the evening primroses faced greater pressure from both deer and mowing. Initially, the rise of the automobile reduced the need to grow hay and graze the meadows as there was no longer a need to feed and stable the horses that brought tourists to Yosemite (Gibbens and Heady, p. 5). At the same time, the burgeoning tourist trade in Yosemite required fresh milk and meat. In the days before refrigerator trucks, fresh milk and meat required local cattle (and a slaughterhouse, from which Slaughterhouse Meadow in Yosemite Valley gets its name). And local cattle needed hay.

Despite the predations of the plowman and the deer, however, the flower remained an attraction. The July 31, 1922, issue of Yosemite Nature Notes still suggested that visitors go out into the meadows to watch the evening primroses open.

Sounding the Alarm in the 1920s

By the 1920s naturalists in the park had sounded the alarm: the flowers were disappearing. In response, the park service and the concessioner made various attempts to hold onto the tradition of Yosemite’s great flower displays. In the early 1920s, Yosemite’s Curry Company tried to plant wildflower gardens in Curry Village with poor results: “Although plants commonly grazed by deer were avoided, the project was abandoned after three years of unsuccessful attempts to keep out the deer.” (McLelland, Chapter 4, section “Grounds of the Concessionaires”).

During the planning of the Ahwahnee Hotel, a 1927 memo called for a “plant refuge” around the hotel because, “It is well remembered that the meadows many years ago were filled with evening primroses” and other plants (McClelland, Chapter IV, my emphasis). Note that already in 1927, people thought of the spectacular blooms as something that happened “many years ago.”

After a rough start, the plants were fenced in to protect them from deer and elk, the latter having been introduced into Yosemite. In 1929, Horace Albright, the new director of the National Park Service, commented that the Ahwahnee plant refuge was “‘the only place in the valley where native flowers’ could ‘be seen in any profusion’” (ibid.). Around 2010, as I was relating some of this history to long-time ranger Bob Roney, it sparked a memory. He told me that the evening primroses were still there in the early 1970s and, though he didn’t know the history, he remembered watching them open from a seat by the window in the Ahwahnee Dining Room the night he proposed to his wife.

Meanwhile, the park service began maintaining flower exhibits behind the new museum, first with cut flowers gathered from around the park and, beginning in 1929, with a live garden protected from deer. The garden expanded under the direction of naturalist-ranger Enid Michael. In 1935, the curators planted evening primrose. This collection of now-uncommon flowers “became the object of popular evening walks” (McClelland, Chapter IV and Chapter VI).

During my ranger days, I would occasionally encounter long-time park visitors who remembered going to the museum garden in the evening to see the evening primroses open. In 1941, Enid Michael wrote an article for Yosemite Nature Notes (vol. XX, no. 4, p. 30-31) on the “Guests of the Evening Primroses,” about the carpenter bees and sphinx moths. She still waxed poetic about the show the flowers put on as the sun goes down, but she located that show in the Museum Garden, not in the meadows of Yosemite Valley as the author of the 1922 article had done.

Evening Primroses Today

Over time, even the Museum Garden and the Ahwahnee Hotel “plant refuge” disappeared. Now, only visitors with a sharp eye and good timing will find an evening primrose blooming in Yosemite Valley. Every year there is at least one place in the disturbed soil along the roads in the Valley that you can find an evening primrose that has survived the deer. By far the best collection near the park grows along the road just east of Tioga Pass. It is perhaps the last place where, on a good night, you can see hundreds of plants produce perhaps 1000 blossoms. The next best place is our house in a year when we succeed in keeping the deer away.

Humans, Nature and Evening Primroses

The story of the evening primrose in Yosemite raises some interesting questions about “natural” places and whether there is such a thing or, more precisely, whether there is a real difference between “natural” places and other places.

When I first came to Yosemite in 1985, I imagined I was walking through a landscape preserved through visionary action from time immemorial just as it always had been so I could appreciate it in its natural, almost primordial form. The naivete of that young rock climber shocks me now, but both the rock climber and the culture around him have evolved somewhat in the intervening forty years.

Of course, even the most superficial reflection reveals my naïve first impression to be untrue — a landscape formed by the Big Bang, plate tectonics and glaciers has no “original” form outside the Singularity. A slightly deeper reflection would have highlighted the obvious fact that there were virtually no uninhabited places in America in 1450 and still less so in 1850, so there was no primordial, untouched place to preserve in 1864. Still, I imagined that it had changed little over the last few hundred years, setting aside the accoutrements of industrial tourism such as roads, trails, hotels, vacation rentals and rangers.

The understanding that the place I thought of as stable could have changed so much in 150 years took years to appreciate. The hotels were obvious as was the absence of Ahwahneechee hunters. Only over time and with increasing knowledge of natural history, though, did I come to see that large patches of the Valley are almost entirely populated with cheatgrass (Bromus tectorum), which did not even exist in North America until the late 1800s. The common mullein (Verbascum thapsus), which grows widely throughout the Valley, was brought over by Europeans and planted as a medicinal (for stomach ailments). And many of the Valley meadows are full of Kentucky Bluegrass which, despite it’s name, is a Eurasian species, not a native of Kentucky let alone the Sierra Nevada. A century of fire suppression has radically changed the composition of our forests. They are far denser than before and biased toward small, shade-tolerant trees rather than the massive fire-tolerant (even fire loving) trees of the past.

All of that poses an obvious question: what do we mean when we talk about “natural” landscapes and going into the outdoors to experience “nature?” Is Yosemite today, with its roads, hotels, restaurants, exotic Eurasian plants, dense cedar and fir forests, and huge deer population, natural? Was the Yosemite of 1906, with no deer, plowed meadows and a magnificent show of evening primroses in unplowed areas, natural? Was the Yosemite of 1800, with double the meadow and a tiny fraction of the undergrowth that we know today thanks to annual fires set by the Ahwahneechee, natural? Was the marshy valley of 5000 years ago, before the arrival of people, ipso facto more natural than the dry valley that humans lived in? Do humans, by our very presence render a place less natural? It is now clear in the Anthropocene that there is no landscape that has not been influenced by humans, so how do we distinguish between a place like Yosemite Valley and a place like Manhattan?

Once you ask these questions, it becomes clear that simple words like “natural” and “wild” are inexact labels for slippery concepts. Better minds than mine have devoted entire books and careers to wrestling with those questions. Rather than hazarding an answer, I will end with a quote from historian William Cronon:

If wilderness can do this—if it can help us perceive and respect a nature we had forgotten to recognize as natural—then it will become part of the solution to our environmental dilemmas rather than part of the problem. This will only happen, however, if we abandon the dualism that sees the tree in the garden as artificial—completely fallen and unnatural—and the tree in the wilderness as natural—completely pristine and wild. Both trees in some ultimate sense are wild; both in a practical sense now depend on our management and care. We are responsible for both, even though we can claim credit for neither.

Cronon, The Trouble with Wilderness

And that is why I have avoided calling the evening primroses that grow near our house “our plants.” We feel responsible for them, but we cannot claim credit. They are their own plants.

Sources

Many sources are either cited in full or linked in the text. The sources that are mentioned just by author name are here given in full:

• Anderson, M. Kat and Frank K. Lake. “Beauty, Bounty, and Biodiversity: The Story of California Indians’ Relationship with Edible Native Geophytes,” Fremontia, vol. 44, no. 3, December 2016, pp. 44-51.
• Barthell, John F. and Johannes M. H. Knops. “Visitation of Evening Primrose by Carpenter Bees: Evidence of a ‘Mixed’ Pollination Syndrome,” The Southwestern Naturalist, Vol. 42, No. 1 (Mar., 1997), pp. 86-93.
• Benson, Harry C. The Report of the Acting Superintendent of Yosemite National Park to the Secretary of the Interior, 1906 (Washington: Government Printing Office, 1906). For other reports (1908, 1909, etc), it’s a simple matter of looking to the subsection “Game” for the acting superintendent’s comments on the deer population.
• Clark, Galen. The Yosemite Valley, “Flowering Plants in Yosemite,” (1910).
• Cronon, William. “The Trouble with Wilderness; or, Getting Back to the Wrong Nature,” in William Cronon, ed., Uncommon Ground: Rethinking the Human Place in Nature, New York: W. W. Norton & Co., 1995, 69-90.
• Dixon, Joseph S. A Study of the Life History and Food Habits of Mule Deer in California, a reprint from California Fish and Game, vol. 20, nos. 3 and 4 (July and October 1934).
• Ernst, Emil F. “Vanishing Meadows of Yosemite Valley,” Yosemite Nature Notes, vol. XXVIII, no. 5 (May 1949)
• Gibbens, Robert P. and Harold F. Heady. The Influence of Modern Man on the Vegetation of Yosemite Valley (University of California, Division of Agricultural Sciences, July, 1964).
• Jepson, Willis Linn. “Flowers of Yosemite National Park,” p. 254, in the Handbook of Yosemite National Park, edited by Ansel F. Hall (Putnam’s, 1921).
• Pillsbury, Arthur C. Picturing Miracles of Plant and Animal Life (Philadelphia: J. B. Lippincott Press, 1937).
• McClelland, Linda Flint. Presenting Nature: The Historic Landscape Design of the National Park Service, 1916 to 1942 (National Park Service, 1993).