Plain ol’ Texas rat snakes basically match vipers for speed

juvenile Texas Rat snake

STRIKE FAST A Texas rat snake (juvenile shown), common and harmless to people, turns out to strike with the speed of what were thought to be the fastest group of snakes on Earth.

Brad Moon/Univ. of Louisiana at Lafayette

This could be embarrassing for rattlesnakes and other vipers:  Their long-standing reputation as the snakes with the fastest strikes on Earth just got bit by the common Texas rat snake.

In lab tests biting a stuffed glove, Western rattlesnakes averaged speeds of 2.95 meters per second and Western cottonmouths averaged 2.98 m/s, says functional morphologist David Penning of the University of Louisiana at Lafayette. But Texas rat snakes, familiar farmyard chasers of pest rodents, averaged 2.67 m/s. Statistically that’s a three-way tie, Penning and his colleagues report March 16 in Biology Letters

Strikes were over quickly but all species subjected their brains to impressive acceleration. Rat snakes accelerated their head more on average (190 meters per second2)

movie of rat snake strike
STRIKE ONE In a lab, a Texas rat snake strikes a stuffed glove (video is 15 times slower than normal speed). courtesy of David Penning/Univ. of Louisiana at Lafayette
than what a fighter pilot experiences when taking off from an aircraft carrier (27 to 49 m/s 2 ).  

Penning’s point is not that vipers are slow, but that other snakes also evolved a lightning strike.  “They have to eat too,” he says.  Startled mammals have been clocked activating a muscle in as little as 14 to 151 milliseconds.  Snakes in Penning’s tests reached their targets in 50 to 90 milliseconds, literally before some creatures could move a muscle. And if you blink — for a human average of 220 milleseconds — you miss it all. 

Susan Milius is the life sciences writer, covering organismal biology and evolution, and has a special passion for plants, fungi and invertebrates. She studied biology and English literature.

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