The desert kangaroo rats (Dipodomys deserti) is a species of rodent found in desert areas of southwestern North America. These rats are abundant and seemingly defenseless creatures that have to contend with a host of nasty predators, including sidewinder rattlesnakes (Crotalus cerastes). New research shows that desert kangaroo rats frequently foil snakes through a combination of fast reaction times, powerful leaps and ninja-style kicks.
A desert kangaroo rat (Dipodomys deserti) defensively kicking away a sidewinder rattlesnake (Crotalus cerastes) in mid-air. Image credit: Freymiller et al, doi: 10.1093/biolinnean/blz027.
“Both rattlesnakes and kangaroo rats are extreme athletes, with their maximum performance occurring during these interactions,” said co-author Dr. Timothy Higham, a researcher at the University of California, Riverside.
“This makes the system excellent for teasing apart the factors that might tip the scale in this arms race.”
Dr. Higham and his colleagues from San Diego State University, the University of California, Riverside, and the University of California, Davis, documented the interactions between kangaroo rats and rattlesnakes by using radio telemetry to patiently track the hunting behavior of the snakes, and then placing high-speed cameras to record snakes hunting in locations frequented by kangaroo rats.
The videos provide the first ever detailed look at the maneuvers that kangaroo rats use to defend themselves against a deadly predator.
“These lightning-fast and powerful maneuvers, especially when executed in nature, tell us about the effective strategies for escaping high-performing predators,” Dr. Higham said.
“Those that are successful at evading the strike will suggest ways in which the kangaroo rat might be evolving in response to the intricacies of the predatory movements.”
A blink of the human eye can last just 150 milliseconds. In contrast, the scientists found that the snakes frequently launched from absolute stillness to reach the kangaroo rats in less than 100 milliseconds.
They were surprised to find that the kangaroo rats turned out to be even faster, with typical reaction times around 70 milliseconds.
Their data indicate that some kangaroo rats initiated jumps within just 38 milliseconds of a snake starting its strike.
“Kangaroo rats that responded quickly were frequently able to jump clear of the snake completely, leaving the serpent biting nothing but dust as the kangaroo rat rocketed 7-8 body lengths into the air,” said co-author Dr. Rulon Clark, a researcher at San Diego State University.
“But in perhaps the most surprising finding of our research, kangaroo rats that did not react quickly enough to avoid the strike had another trick up their sleeves: they often were able to avoid being envenomated by reorienting themselves in mid-air and using their massive haunches and feet to kick the snakes away, ninja-style.”
The results are reported in a pair of papers published recently in the journal Functional Ecology and the Biological Journal of the Linnean Society.
_____
Malachi D. Whitford et al. Determinants of predation success: How to survive an attack from a rattlesnake. Functional Ecology, published online March 27, 2019; doi: 10.1111/1365-2435.13318
Grace A. Freymiller et al. Escape dynamics of free-ranging desert kangaroo rats (Rodentia: Heteromyidae) evading rattlesnake strikes. Biological Journal of the Linnean Society, published online March 27, 2019; doi: 10.1093/biolinnean/blz027
