Using Dynamic Lights to Provide Chuckwallas with Sunrise, Sunset

November 14, 2019

By Eli Baskir, Manager of Behavioral Sciences

Department of Reproductive and Behavioral Sciences

Every animal in a zoo, big or small, receives enrichment, but enrichment isn’t always new objects or special foods. For some species, enrichment can be the addition of new perches to provide exercise, access to areas with higher temperatures and different vantage points to explore. Changing a habitat by manipulating lights, heat and moisture throughout the day can also be enriching, especially for sedentary, cold-blooded species. 

You’ve probably heard that mammals and birds are “warm-blooded,” while reptiles, amphibians, fish and insects are “cold-blooded.” Warm-blooded, or “endothermic,” species control their body temperature internally through automatic processes like sweating and shivering. Cold-blooded, or “ectothermic,” animals rely on external sources of heat to obtain and maintain optimum body temperatures, and they move between locations with different temperatures in the environment to do so. Reptiles bask, laying out in the sun, until reaching optimum temperature, which energizes them. Optimal body temperatures vary between species and are affected by season, reproductive status, diet and many other factors. If a cold-blooded animal can’t reach optimum temperature, the metabolic consequences include appetite loss, weight gain and reduced behavioral diversity.

Proper lighting and heating are important to ectothermic species. These are provided in our Herpetarium by skylights, lamps and basking areas. Because animals have daily activity cycles, the lamps come on in the morning and go off at night, like flipping a switch. Anyone who has watched a sunrise, however, can tell you that natural light doesn’t turn on and off all at once. Instead, the sun comes up gradually, at first dim but becoming brighter, and sunny or shady spots change location throughout the day.

Our keepers look for new ways to enrich our animals by adding variety and dynamic elements to habitats. In the Herpetarium, dimmer switches were installed on the lights of “Big Desert,” a large habitat near the main entrance. These dimmers allowed independent and incremental brightening and darkening of each of Big Desert’s eight lamps, in order to better simulate the movement of the sun. Before changing permanently to the new switches, we monitored the behaviors of Big Desert’s animals: San Esteban chuckwallas and Gila monsters. In the wild, large-bodied chuckwallas are only active about six hours a day, so it’s crucial that they bask as soon as the sun is fully up. After midday foraging, they return at night to rocky crevices. Gila monsters instead spend their time in cover and near water sources. During this pilot study, we hoped to see an increase in areas of the habitat used by the two species when under a dynamic lighting system. We expected the chuckwallas in particular to move from spot to spot as the lights became brighter because this behavior would occur in the wild. We also wanted to evaluate if this change in husbandry was suitable for these reptiles.

Each species had preferences for specific parts of Big Desert that matched their natural histories: chuckwallas moved to places directly illuminated by spotlight, and, when we used dynamic lights, they moved to follow the brightest areas. Gilas, on the other hand, were under rocks or near Big Desert's water feature, and the movement of the lights didn't affect them as much. Unfortunately, when using the dynamic program, the lamps were no longer on at the same times and intensities, so the temperature in the habitat lowered about 5 degrees. Our system needed tweaking to ensure that lights were changing throughout the day while maintaining the temperature range needed for these species to reach their optimums.

Carefully managing habitat heat is a critical aspect of keeping reptiles and amphibians. In addition to providing adequate temperature ranges, animal care professionals should also consider naturalistic lighting relevant to time of day and season for each species. We are working to supplement Big Desert’s heating in order to ensure that dynamic lighting will not reduce the range of temperatures available to the lizards. When finished, dynamic habitat elements like progressive lighting are unique opportunities for indoor enrichment. For an example you can see right now, please check out the Herpetarium’s mountain chicken frog exhibit. Don’t let the name fool you; these animals are definitely amphibians, not birds! Their habitat has a special feature that periodically simulates the mists, lights and sounds of a lightning storm, and it is a good illustration of how to use variety and change to enrich the animals in our care.

One Health Day 2019

November 01, 2019

Animal health, human health and conservation go hand in hand. In our work, we study all these aspects to better understand the interconnectedness of health for all life on our planet. This defines the concept of One Health. And guess what? November 3 is #InternationalOneHealthDay!

Today, staff from the Saint Louis Zoo Institute for Conservation Medicine (ICM) are leading a blog takeover. Through our posts, we will share some of the work we are doing here in Missouri and around the world for wildlife conservation and human public health. #OneHealth 


One Health includes environmental health!

As humans continue to affect the land, water and air, environmental health continues to be a critical component of #OneHealth issues.  Deforestation, intensive farming practices and compromised ecosystems due to climate change may cause changes in pathogen (i.e., virus, bacteria, fungus) and vector (i.e., mosquitoes, ticks) distribution, contribute to the emergence of new diseases of plants and domestic and wild animals, and interfere with natural balances between species.  Agricultural runoff creates dead zones in oceans and rivers and flushed pharmaceuticals enter waterways and disrupt flora and fauna.  Endocrine disrupting compounds such as BPA (bisphenol A) can change the sex of a developing turtle if exposure occurs during incubation of the egg.  Plastic waste in the environment negatively affects marine and human health.  Click here to learn more about the Saint Louis Zoo Institute of Conservation Medicine Water Quality project.

There is good news, though!  As more people understand that the health of the environment and ecosystems around the world is linked to both human health and preservation of critical species, both individual actions and public pressure can cause positive change.  Visit to learn more.   

Wild tortoises in the Galapagos Islands are carrying antibiotic resistance genes (ARGs). These ARGs are an increasingly important public health challenge globally due to the overuse of antibiotics in domestic animals and humans, leading to spread of bacteria in the environment that are resistant to commonly used antibiotics. This is a great example of #OneHealth and why we must work together to better understand and mitigate human impacts in our ecosystems. 

Local students are taking part in #OneHealth!

Spending time in nature is a proven way to benefit human health, so the Saint Louis Zoo Institute for Conservation Medicine (ICM) team is getting kids into nature through the St. Louis Box Turtle Project. This program enhances school STEM initiatives by allowing students to help field scientists gather data through radio telemetry of tagged turtles in Forest Park, Tyson Research Center and Little Creek Nature Area. Students in the Ferguson-Florissant, Hazelwood, SLPS, and Clayton School Districts are helping to raise awareness of box turtle conservation while gaining field biology skills and improving their overall health. The ICM team is proud to be supporting our future conservationists! 

As climate change has made parts of Kenya hotter and drier, many Kenyans have switched from raising cattle to more heat- and drought-tolerant camels. Making sure these camels are healthy is a key part of ensuring healthy food for people and protecting Kenya’s rich and diverse wildlife from diseases that camels may carry. In April 2019, the Saint Louis Zoo Institute for Conservation Medicine (ICM) partnered with the International Livestock Research Institute and the Smithsonian Global Health Program to hold a course on dromedary camel health for Kenyan veterinarians. Veterinarians from around the country gathered for five days of hands-on training, knowledge sharing, and the creation of a community of practitioners better prepared to protect the health of Kenya’s livestock, wildlife and people.

One Health is Community!

Messaging to our communities about conservation is very important.  We are all part of our ecosystems and we must understand how our behaviors affect the other species that share these ecosystems with us. By connecting with communities, locally in St. Louis and around the world where we work, we are building a network of #OneHealth practitioners that will help us make the world a better, healthier place for all.  Healthy animals, healthy people!

#OneHealth is evolution, and evolution implies constant and natural change.  Species are continually adapting to their environments, which includes fighting off diseases to survive.  However, pathogens and parasites are also constantly evolving to “outsmart” their animal hosts’ defenses.  As a result, many species and their diseases are in a constant arms race to keep from going extinct. This is a natural process, but one that is being thrown off-kilter by recent human-induced environmental changes. We are working to understand these complex systems by measuring how these changes affect wildlife health, and by extension, human health. For instance, we found that Galapagos giant tortoises that live closer to humans have more antibiotic-resistant genes than tortoises that live farther away. This might make them more susceptible to diseases, which is crucial information for developing effective conservation management plans and saving species.  Will Galapagos tortoise species be able to adapt to changes caused by encroaching human populations?


Artificial Intelligence (AI) for One Health

The Saint Louis Zoo Institute for Conservation Medicine (ICM) has been collaborating with the Saint Louis University Remote Sensing Lab over the last year to explore ways that emerging platforms to manage digital devices, also known as the "Internet of Things" (IoT),  might also help connect field research with satellite imagery of our changing planet to support better, faster conservation medicine. With cloud computing support awarded through a Microsoft "AI for Earth" grant, Zoo staff and SLU researchers are developing new techniques for connected conservation and applied remote sensing throughout the world, from Kenya to Madagascar. The team's tech lead, Stephen Leard, an IT Analyst within the Zoo's Technology Services department and graduate student at SLU, had the opportunity to accompany ICM veterinary scientists to Kenya in spring 2019 to learn more about veterinarians' technological challenges in the field. That experience and this ongoing collaborative research demonstrates how the Zoo continues to utilize state of the art technology for One Health worldwide!


A Book on One Health

If this #FacebookTakeOver day and the stories shared by the Saint Louis Zoo Institute for Conservation Medicine (ICM) staff has sparked your interest in One Health, you may want to check out the book, Introduction to One Health: An Interdisciplinary Approach to Planetary Health, which we published in 2019. The book covers the what, where, when, why, who, and how of One Health and is divided into 6 sections: (1) An Introduction and Impetus for One Health, (2) The One Health Triad, (3) Practitioners and Their Tools, (4) How to Start a Movement, (5) Humanities of One Health, and (6) Where Do We Go From Here.. A book like this is just in time. With the growing evidence of the global challenges that threaten animal, environmental and human health, we must take action to overcome these challenges. The true value of One Health is that it is a solutions-based, transdisciplinary approach to tackle the planetary health challenges of the 21st century. One Health as an approach will help us ensure healthy animals, healthy people and a healthy planet. 

Ode to the Tasmanian Devil

October 29, 2019

By Shannon Santangelo, Children's Zoo Keeper

Our loud growls and screams may give you a fright,
If you were wandering about on a dark Tasmanian night.

Our gaping, teethy mouth you might think is quite ferocious,
But it's typically just a yawn, and we are rather shy with hiding skills considerably precocious.

Sporting black and white fur and small red ears,
We carry young in a pouch and live about five to six years.

We enjoy eating a variety of both fresh and old meats,
Wallaby, possum and wombat are just a few of our favorite treats.

Bones and fur are no test for our powerful jaws,
And our long, sharp teeth are rather useful as we gnaw.

We prefer to live alone as we sleep or roam,
But you may hear us loudly sharing a meal nearby our home.

Resting in our dens is where we spend most of our day,
But a nice swim or nap in the sun is quite enjoyable if we may.

Our wild friends are threatened by a fatal disease,
And unfortunately our frequent biting is how it spreads with ease.

Luckily our human counterparts are here to help save us from extinction,
For an ecosystem without Tasmanian devils would have quite the distinction.

We traveled to the United States to be species ambassadors,
As for now scientists have not yet found any cures.

With the help of the Save the Tasmanian Devil Program, our populations are growing in human care,
And successful releases back into the wild they continue to prepare.

Click a photo to enlarge the image.