I got milked by the Rana Lechera: Trachycephalus venulosus

One frog I didn't get to film while calling is Trachycephalus venulosus, a Hylid treefrog (I wish I had - check out their ridiculous vocal sacs!). I did get to witness the origin of the common name of some frogs in this genus - Rana Lechera, or Milk Frog. Poisonous skin excretions are a common defence among many amphibians. Trachycephalus are a group whose secretions are obvious and include a bit of physical defense as well as chemical.

The very first T. venulosus I encountered on Hato Masaguaral put this defense to good use. I found this big guy roosting inside a parrotlet nest box. I shook him out into the box cap so I could catch him (he was a lifer, after all) and he got rather upset about it. Out oozed the milk!


Their skin secretion was very sticky and glues my fingers together, much like that of Slimy Salamanders (Plethodon glutinosus complex) in the US. It is undoubtedly toxic or distasteful, but I wasn't about to go licking unknown skin secretions in the field. Instead I just played with this big charismatic treefrog for a few minutes, then let him go.


I encountered T. venulosus fairly frequently over my three months at Hato Masaguaral, but none ever milked me to the extent of that first big one.

This one lived in a whole in our gate

A smaller individual in a parrotlet nest box

Did you eat any parrotlet eggs? (Photo courtesy Rae Okawa)

Digging in the nest boxes (Photo courtesy Rae Okawa)

(Photo courtesy Rae Okawa)

(Photo courtesy Rae Okawa)