Do Rattlers Like their Lizards Warm or Cool?
A new study by an 色情视频 doctoral student answers a long-standing mystery about snake predation.
That鈥檚 important to snakes, which rely on this thermal sensing to detect warm prey in cool environments. But a mystery has long faced biologists: Do these snakes prefer certain temperatures of prey to others? It鈥檚 not a question of preferring their meat well-done or rare, explained 色情视频 Ph.D. student Hannes Schraft working in the lab of biologist Rulon Clark. Instead, colder prey might indicate those animals鈥� muscles aren鈥檛 ready to run away as quickly as a warmer animal might be.
鈥淕enerally, the colder they are, the slower they are,鈥� Schraft said.
To find out if prey temperature plays into rattlesnakes鈥� predatory preferences, Schraft headed to the deserts outside Yuma, Arizona. He hunted down sidewinder rattlesnakes鈥�89 in all鈥攂y following the curly tracks they leave in the dirt, then showed them the body of one of their favorite desert treats, a green anole lizard.
Before displaying it to the snakes, Schraft warmed up the lizard鈥檚 body with a heat lamp to a variety of temperatures and then observed whether the snake showed interest in it. If the snakes showed more interest in colder prey鈥攖hough not too cold, as that might indicate a dead or sick lizard鈥攖hat would provide evidence that these snakes prefer cooler, unwary prey.
But that wasn鈥檛 what he found. The snakes appeared to show , he reported this month in the Journal of Comparative Physiology A. Instead, his work confirmed previous findings that rattlers pay the most attention to temperature contrasts鈥攁 warm lizard in the cool desert night, for example.
鈥淔or the snakes, seeing these temperature contrasts is like us looking at a black dot against a white background,鈥� Schraft said.
That may not be the whole story, though. Nearly all the snakes he tracked for the study were juveniles, and because snakes鈥� thermal sensory capabilities improve with age, it鈥檚 possible that older snakes do discriminate between warmer and cooler prey. Schraft plans to pursue that question in the future.
Solving these kinds of questions might one day help engineers develop smaller and more energy efficient infrared cameras, Schraft said.
