Hey all,
As a snake ecologist I can confirm snake can reverse, to a certain extent. As Shorty and Martin suggested really tight holes, or surfaces which may snag their ventral scales can prevent from doing so. But in their normal
environment they definitely go backwards! They're very flexible and capable of micromoving their muscles all around their bodies so to go backwards they simply push their muscles in the opposite direction, and if need be they can slightly lift the outside
edge of their ventral scales over what may snag it. It's a slow movement but possible. Also if any rear part of their bodies can grab hold of something they can use it as an anchor to pull them backwards.
Hope that helps 😊
Cheers,
DAMIAN LETTOOF | Wildlife Ecologist
56 Irvine St
Watson | ACT | 2780 | Australia
+61 401 638 351