Snakes are an animal found on a few planets.
Reptiles are not common upon Barsoom, and it was widely believed for some time that snakes were extinct. John Carter however encountered some of these creatures in the caverns between the valley dor and the underground omean sea, revealing that some still live. They are similar to earth snake, but their venom would make the cobra de capello seem as harmless as an angleworm
Although not much is known about the interior world of the moon there is a toxic reptile that is somewhat like a snake called a Rympth.
Earth and Pellucidar
The Mangani of Africa call snakes Histah. Beneath the surface of Earth in the savage land of Pellucidar snakes grow to titanic proportions, in the pheli swamp some grow to such large sizes that they are able to swallow a trachodon.
On Amtor there are many types of snakes. When Carson Napier was locked in the room of seven doors the room was flooded with many varieties of snakes. Snakes with horns, saber-like fangs and ears. Many variations in color also appeared in the room. Blue, red, green, white, and purple were noted. A huge twenty foot specimen was noted as well, this snake was able to kill a Tharban with assistance from the smaller snakes.