Tropical Herps

Together, reptiles and amphibians are called “herps.” They rely on the environment around them--the sun, water, or ground--to generate the heat they need to survive. With a continuous supply of warmth and water, the majority of the Earth’s herp species live in the tropics. All are habitat specialists, with unique adaptations for avoiding predators and acquiring food.

What They Eat
Depending on their habitat, tropical herps eat a variety of terrestrial and aquatic insects, animals, and plants. Sunshine, warm temperatures, and an abundance of rainfall contribute to a wealth of available food. Constant access to food allows them to reach a much larger size than species living in cool climates.

Where They Live
From deserts to forests to saltwater coasts, tropical herps live in a variety of habitats. They can be found along river banks, near oceans, on the forest floor, underground, or high in the canopy. Reptile habitats can change significantly from one species to the next. For most amphibians, life starts in water.

What They Do
A warm climate allows tropical herps to spend less time maintaining body temperature and more time eating, breeding, and producing young. To dodge predators, escape searing daytime heat, and conserve water, many herps are nocturnal (active at night). Diurnal herps (those active during the day) protect themselves using color, camouflage, and even poison.

How They’re Doing
Many tropical reptiles and amphibians are currently endangered or threatened. Tropical habitats are dwindling at alarming rates, and global climate change is altering habitats, breeding seasons, and affecting the entire food chain for many species. Because each species has adapted to fill a specialized niche, disappearing habitats seriously threaten the stability of some populations.

Helpful hints for viewing the animals

At the Minnesota Zoo, look for exhibits featuring pythons, geckos, poisonous frogs, forest turtles, and even the giant Komodo dragon on the Tropics Trail.   

Tropical Herps

Care at the Zoo

Enrichment helps animals demonstrate natural behaviors, adds variety to their day, encourages them to explore their environment, and enhances their entire well-being. Because herps are a large and varied group, keepers provide enrichment based on what each species might experience in the wild.

In the wild, the landscape is always changing. One way to provide enrichment in zoos is by changing an animal’s physical environment. For herps, this might include adding perches to enclosures to encourage climbing, using water features or misting to assist with the shedding of skin, or changing the material on the surface of the enclosure (e.g. wood chips, soil, or moss) to encourage natural behaviors such as nest-building or burrowing. For example, the zoo’s Asian forest tortoises take turns for “summer vacation”. Individuals are rotated between the indoor exhibit and a large outdoor enclosure during the summer months, and given leaf piles in the exhibit to hide under.

Because regulating body temperature is so important for herps, providing them with multiple places to take cover (especially across different temperature and moisture gradients), allows them the opportunity to make choices in their environment. Keepers give our dart frogs coconut halves and bromeliad plants to hide in or lay eggs on, and add moist moss or dry leaf litter to vary the humidity.
 
In the wild, tropical herps eat varied diets. Different types of food and the timing of feedings can provide enrichment at the zoo. Keepers use logs containing insects released on a random schedule to increase foraging behaviors in frogs. For other species, the occasional offering of live prey can be very stimulating. For example, adding earthworms to a turtle’s substrate, or creating a blood trail (made by dragging a dead prey item around the enclosure and then hiding it) in our Komodo dragon enclosure.

Varying the feeding schedules can also lead to an increase in predatory behavior and therefore an overall increase in activity. It can also provide keepers with a way to supplement an animal’s diet with vitamins. Keepers at the zoo prepare pureed mango dollops for our geckos. In addition to being a tasty treat, powdered supplements are sprinkled in the puree. 

Wild snakes flick their tongues constantly in response to different smells. In captive snakes, this behavior can decline over time without introducing them to new smells. One way keepers encourage this natural behavior is by adding the smell of live prey or the shed of another snake to the animal’s enclosure.

Things you can do

Enjoy! Get outside. Explore and value the outdoors.

Learn: Watch and learn about the animals and habitats around you. Amphibians are always a good starting point.

Save: Clean up and protect wild places, especially wetlands, in Minnesota and around the world. If you have a pet or classroom amphibian that is not native to Minnesota, do not release it into the wild.

Get Involved: Create habitat at home. By providing clean water, hiding places, and insects to eat, you’ll be creating an important refuge for native reptile and amphibian species.

Become a Member of the Minnesota Zoo!

 

 

Tropical Herps

Of the 6,000 known species of amphibians in the world, about half may disappear within the next 50 years. Imagine if the world was to lose half of its birds, half of its mammals, or half of its fish……the loss of amphibians is unprecedented. This represents the most extreme loss of species since the dinosaurs.

Why Should I Care?
Ecosystem Health: Amphibians play critical roles in ecosystems, often serving as the base of a food chain.

Agriculture: They perform invertebrate pest control important to agriculture.

Medicine: Some species have been found to produce substances that may provide medical cures for humans.

Indicators: Amphibians are like canaries in a coal mine, warning us of dangers that may threaten us.

Why Are They Disappearing?
Loss of Habitat: As habitats disappear around the world, so, too, do the animals that live in them.

Disease: The most immediate threat to many amphibian species is a fungus that’s moving quickly around the world. The deadly effects of the Chytrid fungus may be increased by the remaining causes.

Climate Change: Even slight changes in temperature and humidity affect these small, cold-blooded creatures.

Pollution and pesticides: Here in Minnesota, certain pesticides have been shown to have an indirect link to deformed frogs. Over-collection for pets and food.

Things the Zoo's Done/Doing

The Turtle Conservation Fund is an exciting new initiative created through the cooperative efforts of three major turtle conservation organizations: Conservation International, IUCN Turtle Survival Alliance, and IUCN Tortoise and Freshwater Turtle Specialist Group. The mission of the Turtle Conservation Fund is to ensure that no species of tortoise or freshwater turtle becomes extinct, and that sustainable and protected populations of each species continue to exist in the wild.

The components of the initiative include three main areas. The first is support and development of breeding colonies, both captive and wild. Second, the fund will help support conservation biology research including field surveys, data collection, reintroduction techniques, and genetic studies. Finally, the fund will support in-country education and training programs in veterinary and husbandry techniques and help with facility enhancement for zoos and rescue centers.

The Minnesota Zoo's Ulysses S. Seal Conservation Grant Program has provided financial support to The Turtle Conservation Fund for its work toward preserving all tortoises and freshwater turtles in Southeast Asia. Staff champions for this project were Tropics Mammals Keeper, Karla Anderson and Tropics Bird Keeper, James Nelson.

Zoos across North America are working to conserve several tropical reptile and amphibian species through cooperative programs called Species Survival Plan (SSP) programs. One of the goals of these programs is to maintain genetically healthy populations of endangered and threatened herp species through managed breeding programs in zoos and aquariums. Currently, the Minnesota Zoo participates in SSP programs for the Radiated tortoise, Asian forest tortoise, and Komodo monitor.

Tropical Herps

Reptiles vs. Amphibians (“Herps”)

How are they different?

	Reptiles	Amphibians
Body Heat	“Cold-blooded”: their body temperature varies with the heat around them.
Skin	Scales or plates (protects)	Moist, breathable (absorbs)
Toes	Claws	No claws
Eggs	Mostly hard, laid on land	Soft, laid in wet places
Young	Miniature form of adults	Mostly different from adults

Tropical Amphibians

Most amphibians lead double lives. From eggs laid in water, young metamorphose from gills to lungs and fins to legs as they develop into adults and prepare for life on land. Nearly half of respiration is carried out through sensitive skin, which amphibians must always keep moist. Because their skin is so sensitive, scientists consider amphibians “bio-indicators,” organisms that reflect the relative health of the ecosystem they live in.

Frogs

Frogs are by far the most abundant amphibians in the tropics—especially the rainforests where rainfall is plentiful and humidity is high.

Diet
The tropics teems with frogs' favorite food: insects. Adults feed on ants, roaches, termites, crickets, locusts, moths, and anything else that crawls or flies and can be snatched up by the flick of a sticky tongue, which for some species also includes small rodents, lizards, and other frogs. Voracious eaters like the White’s tree frog compresses its bulging eyes down into its mouth cavity to help push prey down its throat.

Habits and adaptations
Unlike temperate frogs that need habitats close to bodies of water, most tropical frogs have adapted to life in the trees. Long hind legs and webbed toes make jumping or climbing across leaves and branches to find food and escape from predators easy. Species living in more arid regions have developed a unique adaptaton to the extended periods without rain. They transform multiple layers of shed skin and mucous into a cocoon that protects their bodies from water loss. Wrapped up in these watertight layers, the frogs can remain in a hibernation-like state until conditions improve-up to 10 months. 

Reproduction
Life for tropical frogs is short and many species have developed strategies to increase their chances of reproducing successfully. Poison frogs, for example, lay their eggs in moist places and shortly after the tadpoles hatch, deposit them into “ponds” of rainwater that have collected in leaves or holes in trees. Frequent rains keep the “ponds” full until the tadpoles are ready to leave. Other species lay their eggs on leaves that overhang water and rely on the humidity from the water underneath to keep the eggs moist. Once they hatch, the tadpoles simply drop into the water. Both of these strategies allow the frogs to bypass many of the aquatic predators that would normally prey on eggs in temperate climates.

Poison Frogs
Unlike most tropical frogs that are nocturnal (active at night), poison frogs are diurnal (active during the day). These tiny frogs spend much of the day foraging for food. The unusually bright colors of their skin (black with red, orange, green, blue, or yellow) is meant to advertise their main defense-poison. The frogs secrete poison through their skin that, on contact, can cause hallucinations, severe vascular constriction, or even death to predators that don’t stay away.  The name “dart frogs” or “poison dart frogs” comes from the fact that the rainforest people of Columbia coated their blow darts with the poisonous secretions from the frogs’ skin.

Tropical frogs at the Minnesota Zoo include Blue poison frogs and White’s tree frog.

Tropical Reptiles
Reptile species found in the tropics include turtles, snakes, crocodiles, and lizards. Different species vary widely in appearance, behavior, diet, and habitat. Most lay eggs, but some give live birth to their young. All reptiles are covered with some type of scales. Some scales are highly modified and others too small to be seen. Like amphibians, they are “cold-blooded” (ectotherms) and rely on the environment around them to generate the heat necessary for digestion and other vital body processes.

Forest Turtles and Tortoises
Like all turtles, land turtles have bodies encased in a shell they cannot crawl out of. Unlike the flat, streamlined shells of their aquatic relatives, land turtles typically have dome-shaped shells, making it difficult for predators to take a bite.

Habitat
Forest turtles can be found in a variety of tropical habitats. Radiated tortoises are built for desert life. They are native only to the dry spiny forests and brush regions of the far south and southeast regions of Madagascar. Vietnamese Black-breasted Leaf turtles have sharp, leaf-like shells that blend in with leaves on the forest floor. These turtles live in tropical forests throughout Southeast Asia and on some of the islands of Indo-Australia. Asian forest tortoises like it wet. They spend their days bathing in warm, shallow water or burrowing in the mud of highland monsoon forests across Thailand, extreme eastern India, and Burma.

Diet
Most land-dwelling turtles are herbivores. They feed on a variety of grasses; also fruits, flowers, and in the case of Radiated tortoises, even tough plants like the cactus. Turtles lack teeth, but have very powerful jaws. Species that feed primarily on plants tend to have jaws with serrated edges to help cut through tough leaves.

Reproduction
Turtles use their back legs to dig nests on land. After depositing their soft, leathery eggs, they cover the nest with sand or dirt and walk away. The exception is the Asian forest tortoise. She uses her hind legs to make a mound of leaf litter more than 3 feet wide and 1 ½ feet high. After laying up to 50 eggs, she defends it aggressively for several days.  

The Asian Turtle Crises

Turtles have long been prized in East Asia for food and in traditional medicine. Because of recent economic growth and new wealth, the trade in turtles has exploded. Turtles are long-lived and reproduce far too slowly to sustain the current harvest of over 10 million wild turtles each year. Although international trade for most of Asia’s 90 turtle species is illegal, it is believed that without rapid action most will be extinct within 10 years.

All tortoises are turtles, but not are turtles are tortoises:

	Turtle	Tortoise
Habitat	Found near water	Live on land, including  desert climates
Shell	Flat and streamlined for swimming	Domed to provide protection against predators
Legs and feet	Longer legs, webbed feet for swimming	Stocky legs, rounded stumpy feet

Tropical turtles and tortoises on exhibit at the Minnesota Zoo include the Asian forest tortoise, Indian star tortoise, Radiated tortoise, and Vietnamese black-breasted leaf turtle.

Geckos

These small to medium-sized lizards can be found in warm, tropical climates throughout the world. They come in a multitude of colors and patterns and some species can change color to blend in with their surroundings or turn darker to absorb more heat. Geckos' skin may be rough with visible scales or look and feel smooth and rubbery. They have a lifespan of approximately 16 years.

Habits and Adaptations
Geckos are very social and known for the unique “chirping” or “barking” vocalizations they make when communicating danger or calling their mates. Their toes have special pads that contain thousands of hair-like projections called setae. This allows them to climb and “stick” to nearly any type of vertical surface (including glass) and even run across ceilings. Except for Standing’s Day gecko (diurnal), these lizards are most active at night (nocturnal) and spend their lives in trees.

Defense
Known as the “tigers” of the gecko world, Tokay geckos are very aggressive, often backing up their “bark” with a painful bite. The tail is used to store fat, but will break off along a fracture plane if the gecko is threatened. Predators become temporarily distracted by a wiggling tail leaving the gecko time to escape. Tails eventually grow back, but smaller than the original one. 

Diet
Geckos feed on a variety of small insects, invertebrates, fruit, nectar, small rodents, and even other geckos.

Reproduction
Geckos are egg layers. They lay their sticky eggs in rock crevices and on walls. Depending on temperature and humidity, young hatch after 45-60 days and are fully able to survive on their own. They are sometimes seen as an easy meal by the parent. The females of some species, like Standing’s Day geckos, are attentive to hatchings and will fend off the male at feeding times to ensure the young get a chance to eat. 

Geckos at the Minnesota Zoo: Look for Tokay geckos and Standing’s Day Geckos on the Tropics Trail. Like all geckos, ours can climb almost any surface and can often be seen sticking to the glass in the exhibit.

Monitors

Monitors have long necks, powerful claws, and strong legs. Most species are terrestrial (live on land), although a few spend at least part at of their lives in trees (arboreal). Water monitors, as their name suggests, are semi-aquatic. They are excellent swimmers and use a flattened lateral “fin” on their tail to steer though water in pursuit of prey. The most famous member of the monitor group is the Komodo monitor, also known at the Komodo dragon. Ranging in length from 6-9 feet and averaging 200 pounds, Komodos are the world’s largest living lizards. 

Diet
Almost all monitor lizards are carnivores (eat meat). Depending on the species, they may eat frogs, rodents, birds, fish, crabs, snakes, crocodile eggs and young, or carrion (dead flesh). Komodo dragons ambush their prey; typically boar, water buffalo, and Sambar deer, and inflict a crippling, infectious bite. They then use their keen sense of smell to track down their prey (sometimes for miles) which usually dies of infection within a few days.

Reproduction
Female monitors dig nests under tree roots, termite mounds, or in the ground. Eggs are laid and left unguarded. When they hatch, young are vulnerable to being eaten by the adults and quickly head for the trees for protection. They remain there (how long depends on the species) until large enough to safely interact with adults.

Monitors on exhibit at the Minnesota Zoo include the Water monitor and Komodo dragon.

Learn more about Komodo dragons

Pythons

Pythons are found in Africa, Asia, and Australia, and include some of largest snakes in the world. Most species are equally at home on the ground, in trees, or swimming in warm waters.

Habits and adaptations
This family of snakes prefers to hunt at night (nocturnal) when temperatures are cool. They rely on a special heat-sensing organ located below their jaw to detect warmth radiating from their prey. Special cartilage allows the snakes to “unhinge” their jaw and swallow large prey whole.

Diet
Pythons are constricting snakes. They prey on frogs, lizards, birds, small and large mammals, and even other snakes. They ambush their prey by grasping it with their teeth, then quickly coiling their bodies around it to prevent it from breathing. Eventually the prey dies of suffocation. Large species, like Burmese pythons, may eat a huge meal and then go a year before eating again. Green tree pythons have very long teeth that can bite through the scales, feathers, and fur of their prey.

Reproduction
Unlike most constrictors (Boas, for example) female pythons lay eggs clutches of 15-20 eggs, and then “incubates” them for 2-3 months by coiling her body around them to regulate their temperature.

Pythons at the Minnesota Zoo include the Burmese python and Green tree python. Both exhibits are located on the Tropics Trail.