Amazon Milk Frog

NOTE: Education Animals are “behind-the-scenes” animals & only appear to the public during Educational events. This includes scheduled events or programs such as daily animal mingles, private onsite programs, and zoo reaches. For more information, please reach out to edureservations@lvzoo.org.

Program and General Information
Amazon milk frogs are one of the largest frogs in South America growing up to 4 inches in length. They live up in the tree canopies in the rainforests of South America. While they rarely leave the trees, milk frogs prefer to be near slow- moving water. They are a light gray color with patterns of brown or black banding, which fade as they age. The name “milk frog” does not refer to their color; it refers to the poisonous secretions this frog may secrete when threatened.
Breeding takes place between November and May. Females lay ~2000 eggs in slow-moving water or in water trapped in a tree cavity, where males will come and fertilize them. Eggs hatch within 1 day and metamorphosis from tadpole to adult takes about 3 weeks.

Diet
Milk frog’s diet consists of insects, other invertebrates, and other small amphibians. As long as they can fit it in their mouth, a milk frog will try to eat it!

Milk frogs don’t use their tongue to catch prey like other frog species do, but instead ambush prey and use their front limbs to shove the prey into their mouth. Frogs will actually use their eyes in order to swallow their prey. Frog saliva is very thick and while it aids in keeping prey items in their mouth, it also makes swallowing more difficult. So in order to swallow frogs will push their eyeballs into their mouth cavity and push down on the prey against the tongue. This will increase the pressure inside the mouth liquifying that super thick saliva, which releases the prey from the tongue and forces that prey down the throat.

Habitat and Range
Amazon milk frogs can be found throughout Northern South America, but most commonly in Colombia, Brazil, Venezuela, Ecuador, and Bolivia. They spend the majority of their lives up in the tree canopy and rarely, if ever, descend to the rainforest floor. Because of their highly permeable skin, which allows for easy transport of water and oxygen through the skin, milk frogs prefer high humidity and moist environments. They are often found near sources of water, whether that is slow-moving bodies of water on the forest floor or pockets of water in tree cavities.

Milk frogs are nocturnal (awake during the night), and can be found hidden under leaves and vegetation above streams during daylight hours.

Common Physical Features
Amazon milk frogs are a relatively large frog when compared to other species of frogs in the South America. They range from 2.5-4 inches in length with females being larger than males. Milk frogs are typically light gray in color with patterns of brown or black banding. They also have a long snout, large toe pads, and rough and bumpy skin texture. Juveniles are more distinct in color and have a smoother skin texture; bumps on the skin will form and their coloration will fade as they age. This coloration acts as excellent camouflage in the rainforest’s canopy. Milk frogs are a hardy frog with muscular limbs and large feet.

Adaptations: Milk frogs have large toe pads that allow for excellent climbing; in fact the toe pad of the milk frog can hold up to 14x the animal’s body weight! This is especially beneficial since this species of frog is primarily arboreal.

Their scientific name “Trachycephalus” refers to their rounded snout, which they use for pushing aside vegetation to hide amongst. Their common name “milk frog” does not refer to their coloration but to their poisonous secretions. When stressed or threatened, milk frogs may release a milky-white toxin, that although is not as potent as other frog toxins, can cause a predator to become sick. And not only does this toxin assist in deterring predators, but it also acts as a sort of sunscreen for the frog. Milk frogs can rub it all over to aid in water retention to ensure that they do not dry out in the sun.

Milk frogs also have large vocal sacs and are quite vocal, especially at dusk and dawn when they are most active. Males become even more vocal during breeding season while they try to attract a mate.

Behavior and Life Cycle
Because they are mainly an arboreal (tree-dwelling) species, it is very rare that you would see a milk frog on the forest floor. In fact, the only time a milk frog would come down from the trees is during breeding season. Breeding season occurs during the rainy seasons of November through May. The male is responsible for finding a suitable area to lay the eggs, whether that is in a water filled-tree cavity or other source of water. The male will call to females to come and lay their eggs in the water. The female lays ~2000 eggs in a gelatinous mass, which the male will then fertilize. Once the eggs are fertilized, a male may call for another female to lay a mass of eggs next to the fertilized eggs. He will leave these eggs unfertilized so that they do not hatch and can provide food for the newly born tadpoles. This is the end of parent care, though both parents may remain near the vicinity of the hatching site.

Eggs will hatch within one day, and once the tadpoles hatch they must find their own food source and are left to fend for themselves. It takes about 3-5 weeks for tadpoles to metamorphose into froglets. At this point, the frogs will leave their natal area to find a territory of their own. They reach sexual maturity at 1 year.

Conservation Messaging
Conservation of the Natural World
Although population numbers are stable, habitat loss and pollution are a concern for the Amazon Milk frog and could lead to future decline. Human activities, such as residential and commercial development, farming and ranching, construction of roads and railways, and fishing have all contributed to habitat destruction for the milk frog.

Pollution is another big concern for frog species. Amphibian’s permeable skin can easily allow toxins and pollutants to enter their bodies, therefore, they cannot survive in polluted habitats. Tree frogs are considered an important indicator species that warns of future environmental degradation. If population numbers begin to decline then there is a strong possibility that that habitat could be polluted.

What can we do?
Supporting local conservation efforts and organizations is a great way to help ensure species such as the Amazon Milk frog continue to thrive. Switching to a more sustainable lifestyle can also help. By using public transport, turning off lights that are not in use, reducing the use of plastic, and using more organic cleaning products we can help to reduce pollution in our environments.
Remember the phrase, “reduce, reuse, recycle!”

Never remove an animal from the wild! You might think you are helping it, but most people don’t realize the amount of care and time that goes into caring for these animals, and removing them from their natural environment can be detrimental to the wild populations. And while you may think they would make a cute pet, amphibians have a lot of special requirements, such as heating, humidity, nutrition, light, that all need to be considered before purchasing; and always be sure you are buying from a reputable breeder.

Fun Facts
While not all tree frog species are affected, the widespread infectious fungal disease chytridiomycosis has devastated many wild populations worldwide. Chytrid fungus can infect waterways and can cause the keratinized areas of the frogs to thicken. This hinders the ability to pass oxygen and other gasses through the skin and causes the frog to dry out. We can help prevent the spread of the Chytrid fungus by washing items we take into waterways, rinsing off our boots and shoes after being in waterways, and by not handling any wild animals.

Milk frogs are also known as “mission golden-eyed tree frogs” because of their unique yellow/copper eye color.

Bibliography
https://www.npr.org/sections/thetwo-way/2017/01/31/512622260/to-catch-prey-frogs-turn-to-sticky-spit
http://beardsleyzoo.org/amazonmilkfrog-fk1
http://www.iucnredlist.org/details/55823/0 http://amphibianrescue.org/tag/trachycephalus-resinifictrix/ http://www.auduboninstitute.org/animals/frogs-beyond-green/amazon-milk-frog-3022 http://www.clemetzoo.com/animals/index.asp?action=details&camefrom=exhibit&name=RainForest+Amphibian+Exhibits&animals_id=1196
https://www.sfzoo.org/amazon-milk-frog/
https://www.saczoo.org/wp-content/uploads/2016/12/Amazon-Milk-Frog-Factsheet.pdf

Axolotl

Physical Description

Axolotls are neotenic salamanders (meaning they retain certain larval characteristics as adults) that remain aquatic their entire life. They average 6-18 inches in length and weigh 2-8 oz. Wild axolotls are typically dark in color and have the ability to shift their hue a few shades lighter or darker as needed for camouflage. They have feathery external gills, but they also have fully functional lungs. They also have long tails, four legs and large, flat heads.


Predators

Some predators they may encounter include predatory birds and larger fish.


Lifespan

They live an average of 10-15 years.


Reproduction

Axolotls breed between March and June. After a mating waltz, the female will lay 300-1,000 eggs and attach them to protective substrate individually. The eggs will hatch 2 weeks later and will have no parental care.


Fun Facts

  • Because of their limited distribution and their fragmented populations due to habitat destruction, axolotls are critically endangered.
  • Axolotls can regenerate their limbs, lungs, heart, jaws, spines, and even parts of their brain over the course of just a few weeks!

Conservation Messaging

In our Reptile and Amphibian (RAD) center you will find many different reptiles and amphibians including venomous and poisonous species of snakes and frogs. Many of these animals fall victim to habitat loss in the wild. Many of the species here are found in South American habitats which are subjected to deforestation, damming of rivers, water pollution, and poor agricultural and management practices.

Eastern Hellbender

Physical Description

Hellbenders can grow to be 12-29 inches long and weigh 5-6 lbs. They have a sleek, flattened head and body; short, stout legs, long, rudder-like tails; and loose flaps of skin that run along their sides. Their color varies from grayish-brown to olive-brown, and less commonly black.


Predators

They can be preyed on by raccoons, river otters, fish, turtles, birds, and even larger hellbenders.


Lifespan

In the wild, they live an average of 30-35 years, but in human care they have been known to live 50 years or more.


Reproduction

During late summer and early fall, males will dig a nest under a rock to attract a female who will lay 200-400 eggs. Females will then leave the nest, so sometimes multiple females will lay eggs in the same nest. Males will externally fertilize the eggs and then stay to guard the eggs until they hatch in about 68-75 days.


Fun Facts

  • The hellbender is split into 2 subspecies: the Eastern and the Ozark. They are the largest salamanders in North America and are the third largest salamander in the world.
  • Hellbenders have lungs, but they use capillaries in the folds of their skin to absorb oxygen from water instead of breathing air. Because of this, it is very important for them to live in clean water.

Conservation Messaging

In our Reptile and Amphibian (RAD) center you will find many different reptiles and amphibians including venomous and poisonous species of snakes and frogs. Many of these animals fall victim to habitat loss in the wild. Many of the species here are found in South American habitats which are subjected to deforestation, damming of rivers, water pollution, and poor agricultural and management practices.

Dart Frog

Physical Description

There are around 200 different species of poison dart frogs, and they are known for having a wide variety of different, brightly colored patterns. They can range in size from 0.75 to 1.5 inches in length.


Predators

Because of a built-up resistance to the dart frog poison, their only natural predator is the fire-bellied snake.


Lifespan

Poison Dart Frogs live an average of 3-5 years in the wild, but they have been known to live 10-20 years in human care.


Reproduction

Breeding times depend on rainfall, but they can typically breed year-round. Rituals vary by species but most include an elaborate courtship that can last several hours. The female will lay clutches of eggs ranging from 1-30 eggs in a moist environment, and both parents typically help the eggs stay moist until they hatch in 2-4 weeks. Some parents will then carry their tadpoles on their backs to a water source where they will stay for the next 6-12 weeks until their metamorphosis is complete.


Fun Facts

  • Poison Dart Frogs earned their name because native people were known to rub blow darts and arrowheads on the three most toxic species of dart frogs in order to add poison to their weapons.
  • Their bright colors serve as a warning to let predators know they have poison and should be avoided. They are unable to produce their own poison and instead use toxins from the insects they eat which have consumed plants with toxins.

Conservation Messaging

In our Reptile and Amphibian (RAD) center you will find many different reptiles and amphibians including venomous and poisonous species of snakes and frogs. Many of these animals fall victim to habitat loss in the wild. Many of the species here are found in South American habitats which are subjected to deforestation, damming of rivers, water pollution, and poor agricultural and management practices.

Lesser Siren

Physical Description

The lesser siren is a type of salamander with two front legs and no hind legs and retains external gills throughout its life. Their color can vary from deep brown to olive green to black. They can range from 7-27 inches in length and have a long, slender tail.


Predators

Predators they may encounter include water snakes, fishes, alligators, and wading birds.


Lifespan

Their lifespan in the wild is unknown, but in human care they have been known to live an average of 6 years.


Reproduction

Not much is known about their reproduction. Scientists believe their courtship rituals may be aggressive and involve biting because of scarring. Females will lay anywhere from 100-500 or more eggs in the soft mud or plant debris at the bottom of the body of water they inhabit. It is believed that the eggs then incubate for 1 ½ to 2 ½ months because of when larvae begin to appear.


Fun Facts

  • The lesser siren is smaller than the greater siren, which can reach lengths of over 3 feet. The best way to distinguish between them is by counting their costal grooves, which are grooves on their sides from the forelimbs to the vent. Greater sirens will have over 36 grooves, while the lesser will have under 35.
  • Because of their body shape and lack of hindlimbs, the lesser siren has often been mistaken for an eel!

Conservation Messaging

In our Reptile and Amphibian (RAD) center you will find many different reptiles and amphibians including venomous and poisonous species of snakes and frogs. Many of these animals fall victim to habitat loss in the wild. Many of the species here are found in South American habitats which are subjected to deforestation, damming of rivers, water pollution, and poor agricultural and management practices.

Tiger Salamander

Physical Description

Tiger salamanders have rounded heads, thick bodies, and thick tails. They can be anywhere from 7-14 inches long. Coloration will vary by subspecies but can be black, brown, gray, or yellow with gray or yellow stripes and/ or spots.


Predators

Tiger salamander eggs and larvae are preyed on by a wide variety of animals including fish, water birds, insects, frogs, and other salamanders. Adults can be preyed on by snakes, skunks, badgers, raccoons, and owls.


Lifespan

They live an average of 12-15 years in the wild but have been known to live longer than that in human care.


Reproduction

Typically, adult tiger salamanders only enter a body of water when they are ready to breed. Courtship rituals vary by species. Females will lay small clusters of eggs which she will attach to underwater plants or debris. The eggs will hatch in about 2 weeks.


Fun Facts

  • Though they rarely enter water as adults, the tiger salamanders still need to keep their skin, moist and so they stay burrowed under leaf litter or in the ground during the day and come out at night to hunt.
  • They have the greatest range of any North American salamander and are one of the largest terrestrial salamanders in the US.

Conservation Messaging

In our Reptile and Amphibian (RAD) center you will find many different reptiles and amphibians including venomous and poisonous species of snakes and frogs. Many of these animals fall victim to habitat loss in the wild. Many of the species here are found in South American habitats which are subjected to deforestation, damming of rivers, water pollution, and poor agricultural and management practices.

White’s Tree Frog

NOTE: Education Animals are “behind-the-scenes” animals & only appear to the public during Educational events. This includes scheduled events or programs such as daily animal mingles, private onsite programs, and zoo reaches. For more information, please reach out to edureservations@lvzoo.org.


Program and General Information

White’s tree frogs are an adaptable species native to Australia and New Guinea. They are rather large ranging from 3-5 inches in length. Although they can live in both dry and wet habitats, white’s tree frogs prefer damper tropical forests and scrublands. They are commonly a light bluish-green to emerald green color, but they do have the ability to change their color to a more brownish color or darker green. White’s tree frogs have a thick cuticle and can secrete a milky-white substance called “caerviein” to keep moisture in; both adaptations allow the frog to survive in more arid environments. Breeding occurs in summer in grassy, rain- filled marshes. Females can lay clutches of 150-300 eggs, which hatch 1-3 days after fertilization and metamorphose 2-3 weeks later.


Diet
White’s tree frog’s diet consists of insects, spiders, moths, roaches, and even smaller mammals and amphibians. As long as they can fit it in their mouth, a frog will try to eat it!

White’s tree frogs don’t use their tongue to catch prey like other frog species do, but instead ambush prey and use their front limbs to shove the prey into their mouth. Frogs will actually use their eyes in order to swallow their prey.

Frog saliva is very thick and while it aids in keeping prey items in their mouth, it also makes swallowing more difficult. So in order to swallow frogs will push their eyeballs into their mouth cavity and push down on the prey against the tongue. This will increase the pressure inside the mouth liquifying that super thick saliva, which releases the prey from the tongue and forces that prey down the throat.


Habitat and Range

White’s tree frogs are an arboreal (tree-dwelling) species native to Northern, Eastern, and Southern Australia, as well as, Southern New Guinea. They can live in seasonally dry and wet habitats but prefer moist forested and scrubland environments. Because they are so adapted to living in more arid regions, white’s tree frogs can also be found living in suburban and agricultural areas with humans.

While primarily nocturnal, white’s tree frogs have been known to be active during the daytime. Being an arboreal species, these frogs spend the majority of their time higher up in the trees.


Common Physical Features

White’s tree frogs are one of the larger species of frogs ranging from 3-5 inches in length. Females do tend to be bigger than males. They are typically a light bluish-green to emerald but do have the ability to alter their color to a darker brown or green. White’s tree frogs have large webbed toes and a second finger that is longer than the first. Their pupils are horizontal and they have a distinctive fatty ridge over the eyes, often giving them a sleepy look. Males are more slender in appearance than females and have a grayish wrinkled vocal sac that is located underneath the throat region.

Adaptations: White’s tree frogs are excellent climbers. Large adhesive pads on their toes and fingertips, sticky webbing between their toes and finger, and loose skin on their bellies all enable the White’s tree frog to cling to surfaces for climbing. Extra cartilage between the last 2 bones of each toe allows for greater mobility to grip onto thin twigs.

White’s tree frogs have binocular vision. Their nostrils and large eyes sit high on the head, so when the frog is sitting in the water it can breath and watch for food and predators with the rest of its body hidden in the water out of view.

They are well adapted to living in more arid environments. Their skin is covered in a thick cuticle to help with water retention making these frogs fairly drought resistant. To further aid in keeping in moisture, White’s tree frogs secrete a milky-white substance called “caerviein,” which they will coat their body in. This coating acts like sunscreen to protect the frog from drying out in the heat.
During the dry season, White’s tree frogs will cover themselves in a cocoon of shed skin and mucus and burrow to keep moist.


Behavior and Life Cycle

For most of the year, White’s tree frogs call from high positions, such as trees and gutters. During their summer breeding season, the frogs descend, although they remain slightly elevated, and call close to still-water sources. Females can lay clutches of 150-300 eggs. These eggs will hatch 1-3 days after fertilization and metamorphose from tadpole to froglet within 2-3 weeks.

Like many frog species, White’s tree frogs call not only to attract mates but also to advertise their location outside the breeding season, usually after rain, for reasons that are uncertain to researchers. They will emit a stress call whenever they are in danger, such as when a predator is close or when a person steps on a log the frog resides in.


Conservation Messaging

Conservation of the Natural World
Although population numbers are stable, habitat loss and pollution are a concern for the White’s tree frog and could lead to future decline. Human activities, such as residential and commercial development, farming and ranching, construction of roads and railways, and fishing have all contributed to habitat destruction for the White’s tree frog.

Pollution is another big concern for frog species. Amphibian’s permeable skin can easily allow toxins and pollutants to enter their bodies, therefore, they cannot survive in polluted habitats. Tree frogs are considered an important indicator species that warns of future environmental degradation. If population numbers begin to decline then there is a strong possibility that that habitat could be polluted.

What can we do?: Supporting local conservation efforts and organizations is a great way to help ensure species such as the White’s tree frog continue to thrive. Switching to a more sustainable lifestyle can also help. By using public transport, turning off lights that are not in use, reducing the use of plastic, and using more organic cleaning products we can help to reduce pollution in our environments. Remember the phrase, “reduce, reuse, recycle!”

Never remove an animal from the wild! You might think you are helping it, but most people don’t realize the amount of care and time that goes into caring for these animals, and removing them from their natural environment can be detrimental to the wild populations. And while you may think they would make a cute pet, amphibians have a lot of special requirements, such as heating, humidity, nutrition, light, that all need to be considered before purchasing; and always be sure you are buying from a reputable breeder.


Fun Facts

  • While not all tree frog species are affected, the widespread infectious fungal disease chytridiomycosis has devastated many wild populations worldwide. Chytrid fungus can infect waterways and can cause the keratinized areas of the frogs to thicken. This hinders the ability to pass oxygen and other gasses through the skin and causes the frog to dry out. We can help prevent the spread of the Chytrid fungus by washing items we take into waterways, rinsing off our boots and shoes after being in waterways, and by not handling any wild animals.
  • Said to be able to alter how much water evaporates from their skin, White’s tree frogs may be able to slightly control their temperature (impressive for a cold-blooded animal).
  • Extracts from the skin have medical uses such as fighting staphylococcus bacteria that can cause abscesses, lowering blood pressure, and treating cold sores caused by the herpes virus.

Bibliography