Herpetarium

San Esteban Chuckwalla

The Chuckwalla is from the San Esteban Island, located in the Gulf of California. They enjoy dry, rocky deserts, desert woodlands, and scrublands. All habitats are characterized by the presence of creosote, prickly pear, and kittlebush, which are the main sources of food for chuckwallas. San Esteban Chuckwallas are the largest of five species of Chuckwallas, which are part of the Iguana family. A large adult may be up to 24 inches long and weigh up to 3 pounds! Male chuckwallas are typically larger and more brightly colored than females. They love to eat blossoms from creosote and prickly pear plants, kittlebush leaves, and other leaves, fruits, buds, seeds, as well as the occasional insect. Chuckwallas don’t ever drink! They get all of their water from their food. This is an adaptation to living in a dry, desert environment.  Courting and mating occur in the Spring. Males will become brighter and begin competing for territories by head bobbing, mouth gaping, and push-ups. Females enter the male's established territories for mating, and will lay 5 to 16 eggs in an underground nest cavity. These eggs will hatch after an incubation period of 90 days. Hatchling chuckwallas emerge from their nests in late summer to early fall and there is no parental care. Adult males can reproduce annually, but females typically only mate every 2 to 3 years. Their predators are birds of prey, coyotes, and rattlesnakes. Chuckwallas rely on their camouflage to avoid detection by predators. They also have excellent peripheral vision, which allows them to detect threats early. If they feed threatened, they will run to the nearest rock pile and hide in the crevices. They can also inflate their bodies by taking a deep breath, and wedge themselves into those rock crevices, so that they are nearly impossible to get out. As a last measure of defense, the chuckwalla will use it’s tail as a whip to try and deter a predator. San Esteban chuckwallas are the rarest of the chuckwallas, and have been listed as endangered since 1980. Collection for the pet trade has taken a toll on their populations. They also face habitat destruction due to the introduction of invasive species (like cats, rodents, and livestock) which may prey on the chuckwallas directly, or compete for food. They can live for over 25 years!

The Memphis Zoo is home to two San Esteban Chuckwallas. The male, named "Darwin", was hatched at the Arizona Sonoran Desert Museum October 17, 2010, and came to the Memphis Zoo in 2016. The zoo also has one female, named Alyssa. She hatched at the Arizona Sonoran Desert Museum in October of 2005, and came to the Memphis Zoo in 2007. These chuckwallas live together in the back area of the Herpetarium, and although they are not on exhibit, they are quite friendly and you may be able to see them out for one of the Herpetarium Keeper Chats.Fun fact: baby chuckwallas are on their own as soon as they hatch, as there is no parental care in this species and a chuckwallas main line of defense is to run to the nearest rock pile, and wedge itself into the crevices. 

Milk Frog

Galapagos Tortoise

The Galapagos Tortoise is from the Galapagos Islands west of the Ecuadorian mainland. Their habitats range from hot, dry, volcanic terrain to lush green vegetation, depending on which Galapagos Island you find them on. They also vary in appearance depending on the island you find them. The tortoises living on the dryer, hotter islands have a more saddle-backed shell, while the tortoises living in more lush green vegetation have a more domed shell. These are the largest living tortoise species, living to over 100 years, and weighing up to 900 pounds. They love to snack on fruits, vegetables, variety of grasses and cacti. Mating occurs at any time of year but is more frequent in the months of February and June. Females dig nests about 12 inches deep in dry sandy coastal areas. She then lays up to 16 round, hard-shelled white eggs. Once the nest is covered, the female will leave the nest to let it incubate in the sun. The sex of the babies can be determined by the temperature at which they are incubated. Higher temps, 88 degrees and above, produce more females while lower temps, 82 degrees and under, produce more males. Depending on how hot the nest is incubated, it can take 4 to 8 months for the eggs to hatch. The Galapagos Hawk is the biggest predator on the islands. Feral pigs, cats, dogs, and black rats are also predators to baby tortoises. As adults, humans are their biggest predator due to over collecting for their meat and the exotic pet trade. They have hard shells to help protect them from the elements and predators. Over collecting by humans for their meat and the exotic pet trade, as well as habitat loss are some other threats they face in the wild. Their conservation status in the wild is listed as endangered. The Galapagos tortoise is now strictly protected on the islands, making it illegal to collect them for food, pets, or any other animal trades.

Here at the zoo, we currently have 3 large males (all brothers) that spend the summers in the tortoise lots by the Dragon's Lair. We have Frank, Al and Fred. They came to the zoo on December 3rd, 2016. They were hatched in September 1992.T he Galapagos tortoise can go up to a year without eating! The Galapagos tortoise cannot leave its shell. Unlike the cartoons, the tortoise's shell is connected to their ribs, making it impossible for them to leave their shell. Finally, when two male Galapagos tortoises ''fight'', they will glare at each other with their mouths open and stand as tall as they can with their necks stretched as far as they can stretch? The tortoise that stands the tallest is the winner.

Burmese Python

Burmese pythons are native to Southern and Southeast Asia.  They have been introduced and are considered invasive in the Florida. Burmese pythons are mostly found in jungles and marshlands. They are never far from a water source. Burmese pythons are one of the largest snakes in the world.  Wild individuals can reach 16 feet long and 200 pounds.  Females are slightly longer and heavier than males, but both sexes have the same dark coloration with brown rectangular blotches down their body. The Burmese python's diet consists mostly of small mammals and birds. They kill by biting and constricting their prey until it succumbs.  Prey items are then swallowed whole. Burmese pythons tend to be a solitary species and are usually found in pairs only in the spring when mating. Females lay clutches of up to 100 eggs in late spring. The female pythons remain with the eggs, wrapping around them and shivering her muscles.  This behavior raises the ambient temperature surrounding the eggs by several degrees. Once incubated for 60 to 90 days, the hatchlings use their egg tooth to cut out and the mother python leaves the nest. Burmese pythons are preyed upon by tigers, king cobras, and birds of prey.Burmese pythons will bite if seriously threatened.  While they do not have fangs, they do have many rows of short curved teeth used to hold onto their prey. Burmese pythons are listed as vulnerable.  Their numbers are dropping primarily due to habitat destruction, hunting, and being captured for the pet trade. Burmese pythons live a little over 20 years.

At the Memphis Zoo: Our Burmese python is named Elmo and came to us from a private collection in 2012.  He is nearly 16 feet long and weighs around 100 pounds. You can see him on display in the herpetarium and on occasion, sunning with his keepers just outside the west doors of the herpetarium. Burmese pythons are excellent swimmers.  They can submerge and hold their breath for up to 30 minutes! Highly developed heat-sensing pits along the upper lip are used to help stalk and hunt prey. As adults, they can only slither at about 1 mph.

Azure Poison Dart Frog

These frogs are found in the Sipaliwini savanna of southern Suriname. Blue dart frogs are commonly found in warm humid rainforest areas near small streams. Blue dart frogs weigh roughly 3/10ths of an ounce and grow to 2 inches in length. Females are slightly larger and longer than males. Both sexes display highly variable color patterns. Blue dart frogs eat a variety of small insects including ants, fruit flies, termites, young crickets, and tiny beetles. The toxic compounds needed to produce their poison are found in their wild diet, specifically ants. Blue dart frogs reach sexual maturity by their first year. Males find a place to perch, usually a rock or leaf, and call to attract the females.  Females will lay five to six gelatinous eggs after a courtship with a male.  Although the female occasionally will help, the male is commonly the caretaker of the eggs for their 10–18-day development. At hatching, the tadpoles wriggle onto their father’s back and are carried to a small rainwater pool often in a bromeliad plant. By twelve weeks old, the tadpole fully metamorphoses into a small froglet and leaves the water. Blue dart frogs have no predators as adults due to being extremely toxic, but often eaten as tadpoles by other amphibians, reptiles, and invertebrates. The bright colors in the blue dart frog are a type of aposematism.  This warns predators of their toxic nature and discourages attacks. Blue dart frogs are listed as least concern, but their threats include deforestation and their removal for the international pet trade. 4-6 years in the wild, 10 years in captivity.

We currently have three adult blue dart frogs on exhibit in the herpetarium as well as 11 of their offspring.  We also display two other species of dart frog. The patterns on each frog are distinct like human fingerprints. In captivity, these frogs are non-toxic.  They lack the toxic substances found in their wild diet. Males often call in more than one female.  In these cases, the females fight, with the winner starting the courtship ritual with the male. 

American Alligator

American alligators are found, mostly, in the Southeastern United States. This can be as far north as Virginia and North Carolina and as far west as Texas, but they are mostly found in Florida – specifically, Everglades National Park. American alligators inhabit swamps, streams, rivers, ponds, and lakes. They prefer fresh water, and may occasionally stray into brackish water, but are less tolerant of salt water than crocodiles. In the winter, American alligators den underneath banks or clumps of trees. When the water begins to freeze, they go into brumation and stick their snout above the surface of the water so they can breathe above the ice. In the summer, males generally prefer open water, while females tend to remain in the swamps to construct nests and lay their eggs. The American alligator is a relatively large species of crocodilian. On average, it is the second-largest species in the family Alligatoridae. Weight varies considerably depending on length, age, health, season, and available food sources. American alligators from the northern end of their range tend to reach smaller sizes. In mature males, most specimens grow up to about 11 ft in length and weigh up to 790 pounds. In females, the mature size is normally around 8 ft with a body weight up to 200 lbs. Adult American alligators may be olive, brown, gray, or black with cream-colored undersides and broad snouts. When the jaws are closed, the edges of the upper jaws cover the lower teeth. American alligators are apex predators. They are opportunists and their diet is determined largely by both their size and age and the size and availability of prey. Most American alligators eat a wide variety of animals, including invertebrates, fish, birds, turtles, snakes, amphibians, and mammals. Once an American alligator reaches full size, any animal living in or near the water is potential prey. The breeding season begins in the spring. Both males and females bellow loudly by sucking air into their lungs and blowing it out in deep-toned roars to attract mates and claim territory. Large bellowing choruses commonly initiated by females and continued by males. After mating, females will lay 20 to 50 eggs and cover them with vegetation. The temperature the eggs develop at will determine their sex. When the babies begin to hatch, their calls start and the mother quickly digs them out and carries them to the water in her mouth. Snakes, wading birds, osprey, raccoons, otters, large bass, garfish, and even larger alligators will prey on young alligators. Once an alligator reaches about 4 feet in length its only real predators are humans. As human populations increase and housing in low-lying areas grows, encounters with American alligators become more common. American alligators with take a stance with an open mouth as a warning. Their tail is primarily used for swimming but can also be used as a weapon of defense when an alligator feels threatened. Alligators can travel very quickly in water and are generally slow-moving on land, but can lunge short distances very quickly. Historically, hunting and habitat loss have affected American alligator populations. This species gained protection under the Endangered Species Act with allowed the species to recover in many areas where it had been affected. In 1987, the USFWS removed the animal from the endangered species list, as it was considered to be fully recovered. They live for about 30 – 50 years. At the Memphis Zoo: Our American alligator is named Sampson and is an adult male. He is in his early 20s and is always eager to interact with his keepers. He eats a variety of prey items, but his favorite is fish. He is located inside the Herpetarium so be sure to say hi to him the next time you are at the zoo. They have 74–80 teeth, the American alligator is capable of biting through a turtle's shell or a moderately sized mammal bone and infrasonic waves from a bellowing male can cause the surface of the water around its back to vibrate and sprinkle. This is sometimes called the "water dance".