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The Wild Side of the Zoo
From raccoons and red-eared sliders to white-tailed deer and downy woodpeckers, the Zoo is teeming with wildlife that aren’t officially on display.

Getting in free to the Smithsonian’s National Zoo is a nice benefit, isn’t it? Most people think so. But did you know that people aren’t the only ones getting in free? So are some of the animals. But not the ones in the Zoo’s collection—the wild animals that live in Rock Creek Park.

Located on 163 acres, the Zoo offers its non-two-legged visitors a wooded sanctuary in the heart of Washington, D.C. Nationwide, the National Zoo is one of the only zoos set inside a mature forest ecosystem. That means the woods that surround the Zoo have been around for many years. And where you find a forest, you find animals—and lots of them.

Many Mammals

Several mammals native to eastern North America roam the Zoo grounds by day and night, making homes in the park. Some of these include deer mice, Virginia opossums, red and gray foxes, Eastern chipmunks, coyotes, raccoons, white-tailed deer, and several kinds of bats and squirrels (including the flying kind!).

“Thirty years ago, the Zoo actually had an exhibit of white-tailed deer,” says Linda Moore, a biologist in the Zoo’s Beaver Valley. “Back then we rarely saw deer in the Zoo or in Rock Creek Park. But by the time the deer in the exhibit passed away, deer populations had surged again and they were easy to see in the park.”

In the fall, visitors can see deer and squirrels eating nuts under the oak and beech trees in Beaver Valley. The deer gorge on the nuts to bulk up for the winter when food is scarce.

Coyotes also live around the Zoo. According to the National Park Service (NPS), they were first seen around Rock Creek Park in September 2004. Currently, NPS has no estimate of the coyote population in the park, but it believes the number is small. Few coyotes have been spotted in the Zoo.

Interesting Invertebrates

At the Zoo, invertebrates live in more places than their exhibit behind the Reptile Discovery Center. They’re in the trees. On the ground. And inside buildings and out. Some of the most common invertebrates found at the Zoo are moths, butterflies, crickets, arachnids, beetles, katydids, worms, aphids, wasps, bees, and fireflies.

Many of the wild invertebrates that creep, fly, and crawl around the Zoo have characteristics that are just as interesting as the invertebrates in the Zoo’s collection. One of the moths found on Zoo grounds, the hummingbird moth, really looks like a hummingbird. It is large and hovers in place like the bird from which its name is derived.

A beetle that lives at the Zoo, the green June beetle, is among a special group of beetles that pollinate flowers. This beetle is also related to the jade-headed buffalo beetle, an African beetle the Zoo sometimes has on display in the Invertebrate exhibit.

“Some bees we see at the Zoo are quite fascinating,” says Alan Peters, the Invertebrate exhibit’s curator. “Instead of landing on the top opening of a flower like most bees, one bee at the Zoo acts as a ‘nectar robber.’ It has been known to pierce the base of a flower and take the flower’s nectar. It does all this without getting pollen all over its body or carrying the pollen to the next flower.”

An arachnid commonly seen at the Zoo, the jumping spider, is also unlike its relatives. Most spiders have poor eyesight. That’s why they use their webs as a sort of net to catch prey. But the jumping spider has the best vision of all the spiders. It can even see images, a skill almost unheard of in most arachnids.

Fly Like an Eagle

To see birds at the Zoo, you don’t have to go to the Bird House. Just look up. More than 150 bird species, both migratory and non-migratory, have been spotted at the Zoo. These birds include Baltimore orioles, wood ducks, barred owls, black-crowned night-herons, red-shouldered hawks, red-tailed hawks, Cooper’s hawks, screech-owls, ruby-throated hummingbirds, downy woodpeckers, pileated woodpeckers, and yellow-bellied sapsuckers. Bald eagles have also been spotted around the Zoo.

Many birds nest at the Zoo. One migratory bird, the black crowned night-heron, doesn’t nest anywhere else in D.C. except at the Zoo. Each year around February or March, night-heron scouts arrive at the Zoo, but the bulk of the birds don’t arrive until April. They stay through the summer and typically leave the Zoo in August or September. The night-herons have been coming to the Zoo for at least 100 years.

“We generally get several hundred pairs of night-herons at the Zoo every year,” says Greg Gough, a research biologist at the Zoo. “We usually find them nesting in the trees by the Bird House.”

In addition to the night-herons, a pair of red-shouldered hawks also makes its home at the Zoo. For the past few years, the hawks have nested in Beaver Valley. Three years ago, they were successful in hatching chicks. Animal keepers in Beaver Valley hope they will have chicks again this year. Learn more about watching birds at the Zoo.

Keeping the Animals Apart

For the most part, animal keepers do all they can to keep the animals in the Zoo’s collection separate from the wild animals. But occasionally the animals live in harmony together. “When Maureen [the sea lion] was alive, we had a wood duck raise her ducklings in the sea lion pool,” says Moore. “Maureen was older and never bothered them. I don’t think that could happen again, though, with Calli and Summer [the two young female sea lions currently living in the exhibit]. They are much too curious and active.”

Signs of wildlife around the exhibits are often prevalent. Keepers have seen raccoon footprints around both the seal and sea lion pools in Beaver Valley. At the river otter exhibit, the otters come inside each night. Good thing! One morning before the otters returned to their exhibit, keepers found what they believe to be coyote feces inside the yard.

Up a Creek

In and around the Zoo you can find bullfrogs, green frogs, gray tree frogs, and red-backed salamanders. And many fish live in Rock Creek, including blue-gilled sunfish, red-nosed dace, and blueback herring. “Rock Creek Park recently took down seven barriers to herring and other migratory fish,” says Gough. “This will enable them to travel farther up the creek to spawn. One of these barriers was in the creek just below Amazonia.”

The Zoo is also home to many reptiles, including black rat snakes, garter snakes, eastern painted turtles, DeKay’s snakes, red-eared sliders, and ringneck snakes. “We’ve actually found ringneck snakes in the seal and sea lion pools,” says Moore. “But they can’t harm the animals in the pools because they are very tiny—almost like a worm in size. They are small and black and have a yellow ring around their necks. When we find them we simply remove them and put them back into leafy areas of the woods.”

On warm days at the Zoo, sun seeking turtles gather at the water’s edge, perched on logs, rocks, and creek banks. Because turtles, like all reptiles, cannot generate their own body heat like humans can, they have other ways to warm up. The sun helps raise their body temperatures.

Go Wild

Whether you’re interested in mammals, invertebrates, birds, or reptiles, come meet the animals outside of the Zoo’s collection that make the Zoo even wilder.

This article originally appeared in the spring 2008 issue of Wildlife Adventures.