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Desert Diary
Reptiles and Amphibians/Frog Guts


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There's plenty unknown about the wildlife of the Chihuahuan Desert, but studies done elsewhere may give us a pretty good idea of what's going on locally. Recent studies of frog tadpoles in the East showed an amazing interplay between the environment and the length of the gut—the biologists' term for the digestive system. When raised under crowded conditions, tadpoles had long guts compared to those raised with few competing tadpoles; a longer gut helps garner more nutrition from limited amounts of food. But when raised in tanks having predators in the form of dragonfly larvae, the tadpole guts were relatively shorter and the tail relatively larger compared to tadpoles raised in tanks lacking predators. Tadpoles use their tails to avoid dragonfly larvae, and a bigger tail means a more sure escape; but a bigger tail is expensive, and when it comes to a choice between eating well and being eaten, the choice is clear.

Our native frogs and relatives encounter both crowded condition and predators. What do you bet we'll find the same things here?

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pen and ink



Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.



Pennisi, E. 2005. What's eating you? Science 307:1897.