Amphibians
White's Tree Frog
Litoria caerulea · also called White's tree frog, Australian green tree frog, dumpy tree frog, smiling frog
White’s tree frog is the friendly face of the amphibian world — a big, jade-green, loose-skinned frog with a permanent grin and a temperament to match. It lives cheerfully in Australian bathrooms and downpipes, and its skin is a small pharmacy that researchers have mined for antibacterial and antiviral compounds.
Overview
White’s tree frog lives across northern and eastern Australia and southern New Guinea, in woodland, grassland, and wetland edges — and very often in and around houses, water tanks, and drainpipes. It is a sit-and-wait predator of moths, crickets, roaches, and spiders, and will swallow the occasional small frog or mouse. At 7–11 cm and heavy-bodied, older frogs develop the jowly, “dumpy” look the species is nicknamed for.
The skin pharmacy
The frog’s mucus contains caerin peptides (antibacterial, and shown in the lab to block HIV from infecting cells), caerulein (a painkiller and digestive hormone analogue), and compounds that lower blood pressure. These are studied as templates for synthetic drugs; the frog is not harmed to sample them.
Built for dry spells
White’s tree frog can lay down a waxy waterproof coating, hold a water-saving posture, and rehydrate through a belly “drink patch” rather than by mouth. It is also remarkably long-lived — 16 years and more in captivity.
Status
White’s tree frog is Least Concern, common, and adaptable, though some local populations have been hit by the amphibian chytrid fungus.
White's Tree Frog: common questions
Why does White's tree frog look like it is smiling?
The "smile" is a quirk of anatomy rather than an expression. The frog has a wide mouth with slightly downturned corners, large forward-facing eyes, and — especially in older, well-fed individuals — thick horizontal folds of skin along the jaw and over the eardrum that push the mouthline into a permanent gentle upward curve. Combined with the frog's calm, slow-moving temperament and its habit of sitting hunched with its limbs tucked in, this gives it one of the most human-readable "happy" faces of any amphibian, which is a large part of why it is such a popular pet and a frequent subject of photos and memes.
Is White's tree frog's skin really useful in medicine?
Its skin secretions are a genuine and active area of research, though no mainstream drug has come from them yet. The mucus contains a family of peptides — caerins, caeruleins, citropins, and others — with measurable effects in the lab. Some caerin peptides kill bacteria and fungi and have been shown to block HIV from infecting T-cells and to inhibit the herpes virus in cell culture. Caerulein is closely related to a human hormone and acts as a potent painkiller and a stimulant of digestion. Other peptides lower blood pressure or show anti-cancer activity in tissue studies. Scientists study these compounds as templates for designing synthetic drugs rather than harvesting frogs, and the frog is not harmed to obtain samples.
Do White's tree frogs make good pets?
They are one of the most recommended beginner amphibians. They are large enough to see and interact with, extremely hardy, tolerant of a range of conditions, long-lived, and calm enough that gentle, brief, clean-handed handling is possible — most pet frogs are strictly look-not-touch. They need a tall planted terrarium, a temperature gradient, a large clean water dish, and a varied insect diet, and the single most common mistake owners make is overfeeding, which turns the natural skin folds into unhealthy obesity. Captive-bred animals are widely available and should always be chosen over wild-caught.
What is the difference between White's tree frog and the American green tree frog?
They share the common name "green tree frog" and a general look but are different species from different continents. White's tree frog (Litoria caerulea) is Australian and New Guinean, large (up to 11 cm), stocky, and often blue-green to jade with a fatty, jowly build and a placid nature. The American green tree frog (Dryophytes cinereus) is from the southeastern United States, much smaller and slimmer (about 4–6 cm), bright leaf-green usually with a crisp white or cream stripe down each side, and more active and flighty. They are not closely related — White's belongs to the Australian tree frog radiation, the American to the Holarctic Hylidae.