The deserts of the southwestern United States may be the lair of secret ninja masters: desert kangaroo rats.
Researchers armed with high-speed cameras have captured the complex maneuvers that the rodents (Dipodomys deserti) deploy to avoid deadly bites from sidewinder rattlesnakes (Crotalus cerastes). Two new studies, published online March 27 in Functional Ecology and the Biological Journal of the Linnean Society, offer the first detailed looks at those tricks.
Kangaroo rats can avoid attacks using their extremely sensitive hearing and by drumming their feet on the ground to deter predators, says behavioral ecologist Rulon Clark of San Diego State University. But that doesn’t always work.
Clark and his colleagues had seen rats ambushed by snakes in the wild, only to watch many rodents jump with lightning speed and dart away unscathed. These clashes between reptile and rodent happened so fast that the researchers weren’t sure how the rats dodged death. So the team decided to record the encounters.
“FAST AS LIGHTNING” A desert kangaroo rat fends off a rattlesnake with a powerful kick from its hind legs and leaps away, all within fractions of a second. High-speed cameras reveal the rodents’ remarkable agility.
After capturing 32 skirmishes in the Sonoran Desert in Yuma, Ariz., the researchers identified new defensive tricks. When snakes lunged at the rodents, the rats twisted and contorted their bodies in midair to dodge fangs. Even when snakes managed to bite, some rats kicked their foes off before getting a deadly dose of venom.
The kicking was one of the biggest surprises. “We didn’t expect it would be so effective,” says Grace Freymiller, also a behavioral ecologist at San Diego State University.
After successfully dodging a rattlesnake’s fangs, the rodents used their tails to reorient, land on their feet and retreat.
All of that evasion happens faster than the blink of an eye. One kangaroo rat reacted just 38 milliseconds after a snake started lunging. The rats are “clearly pushing the envelope” of reaction time among vertebrates, Clark says.