Rayback is a two-legged carnivores. They resemble the Arrowtongue, but are smaller, faster and more aggressive.
The Rayback is a bipadalien (it has two legs) with a roughly dinosaur-shaped body. Its tail is somewhat like that of a dinosaur's, and it has a prominent phallus. Like almost all animals on Darwin IV, it has no eyes. Its wedge-shaped head is equipped with a sonar mechanism for detecting its surroundings, however, and it also has a powerful dagger-like proboscis. Also it has a long line of red biolights along its back. Its most distinguishable feature is the four tall spines that protrude from its back, from which its name derives. They bear the general appearance of both an Arrowtongue and a Bolt-Tongue, although whether this is due to a close genetic relationship or due to their similar predatory niches is up for debate. Like all Darwinian carnivores, it is a liquivore, feeding by inserting its dagger-like tongue into its victim, pumping in digestive fluids that dissolve the victim's internal organs, and then sucking out the fluid. However, it is preyed upon by Eosapians.
- Hammer-headed Veldt Wing
- Eosapian (possibly)
- Prairie-Ram (possibly)