Reptile and Amphibian Studies

Saint Louis Zoo researchers are identifying the diverse species of reptiles and amphibians that use the various habitats (grasslands, forests, water and more) at the Saint Louis Zoo WildCare Park.

Important First Step

Identifying what species are present on the property is an important first step in making informed decisions about property design and future uses, including collection planning and management, native wildlife corridor management, habitat management and restoration, and educational program development.

Health Studies

An in-depth study of aquatic turtles, such as red-eared sliders, painted turtles and snapping turtles, is taking place within the many lakes and ponds at the WildCare Park. Zoo scientists with expertise in veterinary medicine and reptiles and amphibians are collecting important information about aquatic turtles.

Some of the data they collect include:

  • The number of individual turtles and the species that live on the property
  • Number of males and females and their ages
  • Where the turtles live on the property
  • The turtles' exposure to environmental toxins, like pesticides, lead, arsenic, and others
  • Infectious diseases of conservation concern

The scientists also are looking for diseases in the land-dwelling reptiles and amphibians, such as snakes, box turtles, frogs, toads and salamanders.

Disease Threat

Diseases pose potential threats to the Zoo's future reptile and amphibian conservation breeding colonies at the WildCare Park. Knowing each disease that is currently present on the property and the epidemiology of these diseases (species affected, where they are present, how they spread, etc.) will help the Zoo design effective measures to prevent these diseases in Zoo conservation breeding groups.

Some Discoveries

So far in 2020, researchers have discovered that the WildCare Park ponds support a large number of turtles from a variety of different species. Some turtles use multiple ponds, moving from one pond to another and traveling long distances. Most of the species are small, such as red-eared sliders, but the snapping turtles are the most impressive, weighing up to 24 pounds.

There are booming amphibian populations on the property as well. Many of the smaller bodies of water provide ideal breeding habitat for several species of frogs, toads and salamanders. Amphibians serve as indicator species, meaning they are the first group of vertebrates to show the impacts of potential threats in the ecosystem. These amphibian populations will be an important way for researchers to track the potential impacts of development on the native species.


28 species of reptiles and amphibians have been identified in 2020:


  • Painted turtle
  • Red-eared slider
  • Snapping turtle
  • Three-toed box turtle
  • False map turtle
  • Musk turtle
  • River cooter
  • Yellow-bellied slider


  • Black rat snake
  • DeKay's brown snake
  • Eastern yellow-bellied racer
  • Garter snake
  • Northern water snake

Frogs & Toads

  • American bullfrog
  • Cricket frog
  • Gray tree frog
  • Green frog
  • Leopard frog
  • Southern leopard frog
  • Spring peepers
  • Western chorus frog
  • American toad
  • Eastern American toad
  • Fowler's toad
  • Plains spadefoot toad

Other Reptiles and Amphibians

  • Broad headed skink
  • Small-mouthed salamander
  • Spotted salamander

Water Quality Study

The Zoo's scientists also are trying to better understand the health of the ponds themselves. They test for basic water parameter values, such as dissolved oxygen and nitrate and nitrite levels, like one would do for a home aquarium, and also for possible pesticides and heavy metals.

Dissolved oxygen is essential to the survival of aquatic animals — too much nitrate causes excessive algae growth, which uses up the dissolved oxygen in the water, and high nitrite levels can trigger bacteria growth.

Pesticides are commonly used on golf courses and can migrate into nearby water bodies and cause harm to aquatic plants and animals. Heavy metals can come from a variety of sources. For example, low levels of mercury may be present in the water due to atmospheric deposition from emissions of coal burning power plants.

Lead is found in many areas of Missouri due to past lead mining operations throughout the state. Lead, mercury and other heavy metals do not break down over time and can build up in the blood and tissues of animals such as turtles and cause negative health effects.

Understanding what is, and is not, present in the surface water at the site is necessary to determine what areas are suitable for future animals.

Scientific Methods

Each amphibian and reptile encountered is briefly and safely examined by professional, skilled Zoo herpetologists or veterinary researchers. They record weights and measurements, and for some species, they test for diseases by rubbing a swab on the animal's skin and taking a blood sample.

Some of the ways data are gathered include:

  • Non-invasive acoustic (sound) monitoring around ponds and other water sources
  • Dip-netting into ponds to locate adult frogs, toads, and salamanders, as well as larvae
  • Boards are laid on the ground, and when animals seek refuge under the boards, researchers able to locate and identify them
  • Observers walk the property transects (sample areas) and search natural covers for snakes and other land animals
  • Basking and hoop nets placed overnight in the ponds to catch aquatic turtles

The health, safety and psychological well-being of the animals included in all of the studies are priorities for Zoo researchers. Only skilled personnel handle animals for species ID or health assessment purposes. These interactions are for the shortest amount of time possible and the animals are released back to their wild habitats after the necessary data collection is complete.


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