Birds fly (of course) and some squirrels fly. Some dinosaurs flew. There’s an old saying that something will occur "when pigs can fly." If you change that to snakes, it means it WILL happen, because these have been discovered in South Asia–climbing up trees then flinging themselves off their perches, flattening their bodies, and gliding from tree to tree or to the ground.
Scientists have recovered fossils from a 60-million-year-old South American snake whose length and weight might make today’s big snakes seem cute and cuddly.
The size of the snake’s vertebrae suggest it weighed 2,500 pounds and measured 42.7 feet from nose to tail tip. Geologist David Polly says, “At its greatest width, the snake would have come up to about your hips. The size is pretty amazing. But our team went a step further and asked, how warm would the earth have to be to support a body of this size?”