EPOW - Ecology Picture of the Week

Color of the Tree Frog

Pacific Tree Frog (Pseudacris regilla), Family Hylidae
Columbia River Gorge, Mosier, Oregon USA

Explanation:  What color is a Pacific tree frog?

Green, you say?  OK, this female Pacific tree frog I caught up the Columbia River Gorge in Oregon is definitely green.

But ... studies of this species suggest that there is a largely unstudied form, a "morph," that changes color ... from green to brown.  

Why would it do that?
  

  
The color change may have to do with changing seasons ... when leaves that were green then turn ... well, brown.  

So the frogs can better hide.  Think how well this frog stands out in my hand in the hand in the top photo, above; so it would, among tan and grown foliage or down leaves on the ground, quite a target for many predators.  

So if you're out hunting for Pacific tree frogs -- but not as a predator, please -- you might change your search image depending on the season!

Information:
     Wente, W. H., and J. B. Phillips. 2005. Seasonal color change in a population of pacific treefrogs (Pseudacris regilla). Journal of Herpetology 39(1):161-165.
     Stegen, J. C., C. M. Gienger, and L. Sun. 2004. The control of color change in the Pacific tree frog, Hyla regilla. Canadian Journal of Zoology 82(6):889-896.