Herpetologists at Panama’s Smithsonian Tropical Research Institute have uncovered a here-to-fore unknown form of communication among frogs. Using robotic frogs, infra-red lights and accelerometers, they have established that male Red-Eyed Treefrogs (Agalychnis callidryas) compete by shaking their bodies, which in turn vibrates the plant stems upon which they are perched.
Writing in the May 20, 2010 edition of Current Biology, researchers speculate that the vibrations sent through plant stems enable other male frogs can access the plant shaker’s intent, size and status. It appears that the frogs’ vocal calls may also vibrate plants, but further research is needed.
Additional studies are also being planned to determine if other herps, birds or mammals utilize vibration-based communication (invertebrates are known to do so).
A Hand-Waving Frog
Another frog has forsaken vocal calls – as an adaptation to life near rushing streams that would drown out frog sounds, Panama’s brilliant Golden Frog uses a system of hand signals, known as semaphoring, to communicate. I have observed this in captive frogs and found it most intriguing (please see article below).
The “Bat Effect”?
It’s interesting to speculate just why the Red Eyed Treefrog evolved vibration-based communication (they7 use vocal calls as well).
Many South American bats, such as the False Vampire, feed upon frogs and locate them by homing in on their calls. Certain frog species are known to modify their calls, utilizing a frequency that is difficult for bats to detect…perhaps the Red-Eyed Treefrog has taken this strategy a step further?
Watch and Learn
This research highlights how much there is to be learned about even commonly-kept, well-studied amphibians. Be sure to observe your animals carefully and take notes. The Red Eyed Treefrogs in this study did not vibrate under regular light…you may wish to consider using night viewing bulbs http://www.thatpetplace.com/pet/cat/infoL3/23921/category.web in your quest to uncover further surprises.
Vibrations are also important to this species’ eggs – they hatch spontaneously when attacked by snakes. Read more here.
For more info on frog hand signals, please see The Unique Panamanian Golden Frog.
Red eyed Tree Frog (second image) image referenced from wikipedia and originally posted by Graham P. Oxtoby