Tuesday, March 22, 2016

White's Tree Frog

The Eatles have been busy munching away for the first time on a non-mammal vertebrate! Specifically, they are devouring the soft tissue remains of a White's Tree Frog (Litoria caerulea) from Grant's Farm in St. Louis, MO, named Nona.

White's Tree Frog. Photo from Animal Diversity Web.
Also known as the Smiling Frog, and the Dumpy Frog, this animal is fascinating. It belongs to the Hylidae family of frogs, which is an interesting group because it is united by a single morhpological character shared by all of its members (well, almost all...): claw-shaped terminal phalanges (bones of the fingers and toes). White's tree frogs are native to Australia, Indonesia, and New Guinea, and they live mostly in rainforests and coastal areas. They are usually bright green in color (before The Eatles get ahold of 'em), although the color of their skin can range from brown to light blue and even gray. These frogs are arboreal, as their name implies, and therefore their diet consists largely of insects like moths, locusts, and roaches. But that's not all! They also are known to eat other animals like spiders, worms, and even small mammals (rodents). Because their diet is varied, it is not surprising that they have multiple modes of prey capture. To capture small prey like insects, these frogs extend their sticky tongues and reel in the catch; but to capture larger prey like mice, they will pounce on their victim and force it into their mouth with their hands - much like college students devouring a pizza after a long night at the bar or Buddy the Elf...

One of the most interesting aspects of these animals, however, is their skin. Like all amphibians, they have thin, moist skin that can be easily penetrated by gasses and liquids. This allows them to breathe underwater through gas exchange, without aspirating fluid into their lungs. But the skin of the White's tree frog also possesses a waxy cuticle that prevents water evaporation, which enables it to live in areas farther from a water source, like arid regions or even inside someone's house (they are frequent house "guests" in Australia). The waxy cuticle is interspersed with skin glands that also help to keep it moist. Even more interesting than the waxy cuticle is the fact that the skin secretes a protein that is effective in killing the bacteria Staphylococcus aureus and also in lowering human blood pressure.

We hope you've enjoyed this little diversion into the amphibian world. We are excited to be fostering new relationships with local animal advocacy groups that will lead to more interesting animals being fed to The Eatles. More to come soon, we promise!

Contributed by: Jason Organ, PhD

If you want to read more about White's tree frogs, these papers are a good place to start: 

Boland MP, & Separovic F (2006). Membrane interactions of antimicrobial peptides from Australian tree frogs. Biochimica et biophysica acta, 1758 (9), 1178-83 PMID: 16580625  

Campbell CR, Voyles J, Cook DI, & Dinudom A (2012). Frog skin epithelium: electrolyte transport and chytridiomycosis. The international journal of biochemistry & cell biology, 44 (3), 431-4 PMID: 22182598  

Manzano AS, Abdala V, & Herrel A (2008). Morphology and function of the forelimb in arboreal frogs: specializations for grasping ability? Journal of anatomy, 213 (3), 296-307 PMID: 18565111