Have you ever seen a snake climb a tree? Well, maybe you could have and didn’t want to, but ophiophobia aside, the dance of scales and squeezing that many snake species have evolved is really quite beautiful.
The video above shows a python moving up a palm tree in exacting form. It’s almost mesmerizing how the snake bunches up its muscled body to form anchor points along the way, like the shoe spikes of a power line worker do as he or she ascends.
How do these reptiles pull off this Snake du Soleil? (I know that doesn’t translate just go with it.) Though the general motion is easy enough to categorize, we didn’t know until recently what the snakes’ muscles were up to — what parts of their bodies were squeezing and how much.
Last year, Greg Byrnes and Bruce Jayne at the University of Cincinnati described the snake shimmy by letting five different species slither up a long cylinder lined with pressure sensors and covered in textured tape. What they found, perhaps not surprisingly, was that the snakes were squeezing hardest at the anchor points from which they pulled the rest of their body up the cylinder. (You can watch a video of the applied pressure in real-time here.)
But what was surprising was how much force the snakes were applying to the cylinder. According to the sensors, the snakes were contracting with much more force — a few times their body weight — than should be needed to keep them on the test pole, no matter the angle.
“For a snake, being safe is way, way more important than being cost-effective,” Byrnes told National Geographic. That is to say, for a snake it’s more important to use that extra energy strongly gripping a tree trunk than risking falling to the ground, exposed to predators and back to scale one. The results were published in the journal Biology Letters.
As for the motion itself, it’s called “concertina movement“. Anchoring a portion of serpentine body while pulling the rest up in concert is slow and energy consuming, like having to work an absurdly heavy accordion, but concertina movement (“arboreal”, in this case) is also safe and reliable, as science has now confirmed. And it’s also beautiful, it turns out.