Snakes use waning throb as signal to stop squeezing
A boa constrictor knows to stop squeezing a juicy rat by sensing the heartbeat of its prey, easing up only when the pulse stops, a new study finds.
Detecting heartbeats may give snakes like the boa constrictor an edge for hunting iguanas and other large cold-blooded animals that can cling to life for a long time when cut off from oxygen, researchers report online January 18 in Biology Letters. Taking the pulse of such creatures would be a surefire way to know when to let go.
To pinpoint the snake’s sensitivity to this particular vital sign, researchers at Dickinson College in Carlisle, Pa., started with rat corpses lacking any signs of life. The scientists then implanted pres