“I like that this study is driven by a novel idea, rather than by technology,” says Kate Jackson, from Whitman College. Top: an eastern kingsnake bottom: a corn snake, which is a species of ratsnake. They squeeze in a really haphazard way.” Perhaps that’s why they’re so bad at regicide. Whereas the ratsnakes look like someone dropped spaghetti on something. “The peer reviewers preferred ‘spring-like’, but I call it the ‘curly-fry pattern,’” says Penning. They suspect that kingsnakes instead are stronger because they throw more efficient coils around their prey. They measured how strongly the snakes can pull against a restraint, and found that neither group is better at escaping than the other. They dissected several museum specimens and showed that kingsnakes are no more muscular 2 than ratsnakes. Penning and Moon ruled out two possibilities. They look similar from the outside, but they somehow squeeze much harder. And they found a clear pattern: The kingsnakes exert about twice as much pressure as the ratsnakes. To find out, Penning and his colleague Brad Moon taped pressure gauges to pre-killed rodents, and then offered them to kingsnakes and ratsnakes-182 individuals from six different species. How do you kill something that’s larger than you, using the very same method that it uses to kill? Why don’t kingsnakes ever get counter-constricted? “This is like someone trying to do extreme weightlifting for hours.” “Rarely is someone surprised when the snake wins that scenario.” But kingsnakes will successfully constrict victims that are the same size or bigger, and that are also constrictors. “Big snakes are strong predators small mammals don’t do well when squeezed,” says Penning. Typically, when scientists study constrictors, they look at big ones like pythons or boa constrictors, as they attack mice or rats. And, to Penning, that made no sense.Ĭalifornia kingsnake. Unless it’s a juvenile that has inadvisedly picked on a target several times its size, it always wins. Penning has now watched hundreds of these bouts, and “it never ever seemed like the kingsnake is in trouble,” he says. The ratsnake tries to escape, but almost never does. Then it inches its way toward the victim’s head, alternating between shifting its bite and adding more coils. The kingsnake will launch itself at, say, a ratsnake, bite it, and throw some coils around. They do so by constriction-wrapping their coils around their opponent and squeezing so hard that they trigger cardiac arrest. They’ll take rodents, lizards, and birds as well, but snakes account for a quarter of their diet. These animals get their name because they specialize in killing other snakes. The kingsnake will be the one left slithering. But if one of the combatants is a kingsnake, then all you have to do is wait. “They’re both wound together, just two tubes wrestling,” says David Penning, from the University of Louisiana at Lafayette. When two snakes fight, it can be hard to work out who’s winning.
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