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White’s Tree Frog

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

African Penguins

Physical Description

African penguins, like all penguin species, are flightless birds. Instead, penguins use their small, dense feathers for insulation, repelling water, and protecting their skin. They are stiff contour feathers which overlap each other like shingles on a roof and help keep their skin dry. Underneath them is a thin layer of down feathers which hold a pocket of air. The contour feathers help trap that air and its heat next to the skin.

Having a body shaped like a torpedo or bowling pin helps make them more hydrodynamic so they can swim faster. Their belly is white and may have some black flecks on it, while their back is black. This is called countershading and provides them with camouflage in the water.

Predators

African Penguins have two main predators in the wild; these include sharks and sea lions. Their eggs are preyed upon by kelp gulls and sacred ibis as well as as well as large herons, Cape genet, mongoose, rats, domestic cats, and leopards. Humans also have been known to collect penguin eggs because they have been considered a delicacy.

Lifespan

The average life span for African penguins in the wild is 10-15 years. In human care, the average is 20-30 years.

Reproduction

Large colonies gather together on land when it is time to breed, molt, or rest. African penguins breed year-round, but it can vary depending on the year, season and colony. Primarily monogamous, African penguins will often form the same pair bonds every year. Males will court females with various physical displays, which she will respond to if she is receptive to his courting.

The female will then lay 1-2 eggs about 2-4 days apart. Incubation will last about 40 days. The parents will alternate incubating the eggs and foraging for food in the ocean. When penguin chicks hatch, they will be reliant on their parents for warmth, food, and protection for several weeks. When they are about 70-90 days old, they will finally grow their waterproof contours they need to begin heading into the water on their own.

Fun Facts

  • African penguins experience an annual catastrophic molt. Over a period of approximately 18 days, they will replace all of their feathers, and during this time, they will be unable to feed because their downy feathers exposed during the molt are not waterproof.
  • While diving for food, they average depths of 16-80 feet but can reach depths of up to 300 feet! Having solid, heavy bones (unlike most birds, which have hollow bones), also helps them with be able to dive deeper.

Conservation Messaging

South African penguins are considered endangered but there are many ways we can help their populations in the wild. One easy way to do this is to choose sustainable seafood options. You can download the Seafood Watch smartphone application by Monterey Bay Aquarium to ensure the seafood you’re purchasing is sustainably sourced. You can also download their pamphlet which will provide you with the best fish choices, appropriate alternatives, and certain fish species to avoid when fishing or purchasing food. Making smart and sustainable choices will help ensure that penguins in the wild are left with plenty of fish to eat!

To learn more about the Monterey Bay Aquarium’s Seafood Watch App, visit: seafoodwatch.org.

Another great organization to support is the Southern African Foundation for the Conservation of Coastal Birds or (SANCCOB). SANCCOB is located in South Africa and actually helps rescue, rehab, and release South African Penguins which is helping their wild populations. You can help SANCCOB sustain their mission by donating or by “adopting” a penguin that is currently undergoing care. To learn more or to make a donation, visit: www.sancobb.org.