Eclectic Company

May 15, 2019

How do you care for a venomous snake? Nocturnal mouse? Ancient crocodile? Curator Dan Boehm shares all the things you never knew about Regenstein Small Mammal-Reptile House.

Scaly, furry, slimy, fuzzy, tiny, gigantic. Two, four, six, or eight legs—or none at all! Small mammals, reptiles, and amphibians come in all shapes, sizes, textures, and colors. From itty-bitty cactus mice to hefty spectacled caimans, each species—and individual—at Regenstein Small Mammal-Reptile House has its own set of needs. Curator Dan Boehm and keeper staff care for all of them, a challenge requiring eclectic knowledge of animal physiology, natural history, habitat, diet, social and breeding behavior, and more. Here are a few aspects of care that make this space so unique.

Did you know?
Green tree pythons hatch yellow or red and don’t turn green until around six months of age. Each scale can even be a different color!

Can’t Touch This

Several venomous species reside at Small Mammal-Reptile House, including Rio Fuerte beaded lizards, Aruba Island rattlesnakes, and a white-blotched river stingray. Only specially trained staff care for these species—a multi-step process that only a few keepers have successfully completed.

What’s the difference between poisonous and venomous? Venomous animals bite or sting. Poisonous animals release toxins after being bit or touched.

“You have to have the right mindset to work with venomous animals. You have to be patient, calm, and calculated,” says Boehm.

“It is all about being in mental control,” adds keeper Michal Kisielinski.

Keepers also need to have a great deal of knowledge about animal behavior before working with these species to ensure the safest situation for everyone involved. Safety is the top priority. Venomous animals are enclosed by multiple barriers keepers must negotiate to access their habitats. Additionally, tools are always used to place food items in the habitat or to maintain the exhibit. Lastly, there’s a plentiful stash of anti-venom on zoo grounds. The goal is to never have to use it.

They Can Do What?

“Amphibians and reptiles don’t play by the rules. When people think of frogs it’s usually ‘water-egg-tadpole-frog,’” says Boehm. “Solomon Island leaf frogs, however, skip that whole process. Eggs are laid on land and come out full frog. It’s called direct development.”

The axolotl—an aquatic salamander with feathery, external gills and a finned tail—is another great example. “They’ve adapted for the best chance of survival,” says Kisielinski. In this case, that also means acquiring the ability to regenerate limbs and never evolving to be land species.

Various adaptations among the building’s inhabitants means various needs. Each species can require a precise temperature range, water pH level, curated diet, humidity level, and specific plant life in their habitat—sometimes all at the same time, making caring for these species a scientific balancing act.

From River Beds to Tree Canopies

In the Ecosystem area, there is a multi-species Amazon River habitat with five species: white-blotched river stingray, yellow-spotted Amazon River turtle, Hoffman’s two-toed sloth, white-faced saki monkey, and golden-headed lion tamarin. “Their differences in size, natural history, and diet help in managing them together,” says Boehm.

The key to caring for multiple species is ensuring they all have choices and access to the items they need. The stingray and turtles don’t compete for food because they have different dietary needs, so they can live harmoniously in the river bed without much assistance.

The sloths, sakis, and tamarins are a bit trickier. Since sloths are nocturnal, they eat after hours when the monkeys are in their behind-the-scenes spaces. To ensure the tamarins have a place to enjoy some privacy, a tamarin-sized nest box in the habitat is much too small for the larger sakis to investigate for snacks. These intentional habitat modifications help promote positive welfare for these animals and provide an idyllic habitat.

Dwarf Caiman

Dwarf caiman are one of many unique species with individualized needs and care at Regenstein Small Mammal-Reptile House.

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The building was designed with multiple uses in mind, so the space can be nimble depending on animal needs.

“Regenstein Small Mammal-Reptile House is actually built with many habitats behind the scenes intended for breeding, aging animals, occasional wildlife-trafficking confiscations, head-start conservation programs, and the like,” says Boehm.

Life expectancies for species that live a long time are also considered. Dwarf caiman, for example, endure for decades. Boehm, Kisielinski, and their team have to plan to care for species throughout their entire lives, which means planning habitat and space usage years—sometimes decades—in advance. This adds another layer of complexity to population and habitat planning.

Stress Relief

How do you know when a reptile or amphibian is stressed? It’s not easy.

“The signs are less apparent in these species,” says Boehm. “Appetite loss can be a major indicator of stress or illness in species, but since some reptilians eat so infrequently, our staff has to be in tune with other behavioral indicators.”

Stress hormones can be measured in amphibian skin excretions, but what are some visual clues to amphibian or reptile stress?

Which animal at Regenstein Small Mammal-Reptile House eats the least often? Most of the snakes eat a large meal once every two weeks.

“Skin quality can be an indicator of health or stress in these species,” says Boehm. “Meller’s chameleons, for example, don’t actually change color to match their environment. They change color when they are threatened. When they are stressed, they turn jet black.”

Some signals of acute stress are more apparent, such as the rattle of an eastern massasauga rattlesnake. Chronic stress, however, is harder to detect. The care team pays close attention to subtle shifts in behavior, diet, and skin quality to ensure animals aren’t experiencing increased levels of stress, which can make them more susceptible to illness.


There are also several nocturnal species, including pygmy slow loris, lesser Madagascar hedgehog tenrec, and brush-tailed bettong to name a few. These creatures conduct their foraging and activity at night.

To help highlight some of these behaviors to curious daytime visitors the nocturnal species are managed on a “reverse light cycle.” The care team worked with the Animal Welfare Science Program to create a light cycle that mimics dusk and dawn with habitats being dark during the day, allowing patient visitors with keen vision to view nocturnal behaviors. This is also why guests of after-hour events, such as ZooLights or Adults Night Out, may see these animals snoozing in full “daylight.”

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