Thursday, April 07, 2005

Newt vs. Garter Snake, an Evolutionary Arms Race

IU scientist finds snakes that are keeping pace in toxic arms race

TTX is a defensive compound found in many different animals, including pufferfish, octopuses, and primitive chordates called tunicates. It is used in low concentrations to treat morphine and heroin addicts, and it has been identified as Haitian voodoo’s “zombie” drug.

Evolutionary biologists have long been able to see the results of arms races between predators and prey. Prey often acquire wildly exaggerated traits, such as flying fishes’ airborne abilities or the porcupine’s armor of quills. But the exact way predators, prey and their genes change over time during such races has largely stumped the scientists.

With their new report, the researchers pinpoint a basic mechanism by which the garter snakes keep themselves alive and maintain access to a valuable food source—even if the cost is that the snakes are a little less spry.

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