By Samantha Mathewson | October 20, 2015
Sometimes, being the most poisonous in the bunch isn’t the best defense, it seems. In order to escape predation, many species have evolved to use special defenses that include camouflaging themselves, mimicking other species or using chemicals. For some amphibians that use toxins to protect themselves, the self-defense plan has backfired. Researchers from the University of Liverpool recently discovered that this predatory defense puts animals such as the iconic poison-dart frogs at a higher risk of extinction.
For their study, a team of researchers examined how the rate of amphibian extinction and speciation (the formation of new species) varied based on the use of different defensive measures. While those animals that produced poisonous chemicals as a predatory defense had a high rate of speciation, populations also exhibited a greater rate of extinction, researchers concluded. Ultimately, this leads to a net reduction in species diversification — a combination of both speciation and extinction rates — which the species was trying to avoid by using predatory defenses in the first place, according to a news release.
On the other hand, researchers found that amphibians that changed the color of their skin to hide or those that mimicked their predators to confuse them were using much safer methods of self-defense. The animals that used these techniques were able to both increase and expand (sometimes called “radiating”) their range, and increase the number of species to avoid an increasing rate of extinction, the release noted.
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