EPOW - Ecology Picture of the Week

Obvious Once You See It

American Green Treefrog (Hyla cinerea), Family Hylidae
Jean Lafitte National Historic Park and Preserve, Louisiana, USA

Explanation:  In closeup, this diminutive American tree frog looks obvious, perched on a bulrush stem (note: the above main photo was turned sideways).  But start to back off, and the reason for its coloration and patterning becomes more obvious:

  

  

Green like the reeds it hides in, when this anuran is perched vertically, notice how the white lateral stripe suddenly begins to appear like some of the lighter-colored bulrush stems. 

 

  

  

The stripe also serves to break up the body outline.  

This is disruptive patterning, which makes it more difficult for predators such as herons and snakes to spot the frog when it sits motionless.

 

  

Notice how the dark edging of the eye, and the horizontal pupil, and the dark edging below the white lip stripe, all align, to further break up the body outline.

Also notice how the frog compresses itself so as to leave no space below its body that would otherwise more clearly highlight its outline and become more apparent.

So it is the suite of adaptations of color, body patterns, eye pattern, and behavior that together helps to hide this mostly defenseless prey that is obvious ... only once you see it.