Researchers shine polarized light from beneath a transparent surface covered with a "photoelastic" gelatin as a corn snake slithers in an undated photo. Bright regions indicate where the snake is applying the most force.
Such experiments helped reveal that snakes throw their weight around to speed up their slink, the researchers reported in a June 2009 study.
The reptiles don't lie totally flat on the ground as they move, study leader David Hu said.
"If you imagine you have a shoestring on the ground in the shape of an s,
the curved parts of the s
are lifted slightly, and the remaining weight is concentrated on the middle part of the s."
So snakes will lean on the lifted areas with the most force--an adaptation that allows them to travel much faster.
People move their weight in the same way, Hu added: If a person leans to the right and takes a step, that right foot takes the brunt of the body's weight and provides the most forward momentum.
Photograph courtesy David Hu