It is a leathery-skinned biped with four elongated spines protruding from its broad back. When resting, it squats close to the ground. Like all Darwin IV creatures, it does not have any eyes on its triangular head. Instead, it navigates with a barrage of high-pitched sonar pings when needed.
When a rayback quickens its pace to a fast trot, leaping over broad ravines and pushing through the thick grass with ease, it can bring its speed up to a formidable 45 kilometers per hour (almost to 50) and can cover the terrain of the plains with great leaps.In pursuit of prey, a rayback can cover almost 5 kilometers, with both animals careening in wide turns and bounding over rocks and depressions. Even though a rayback can be clocked at 48 kilometers per hour, certain difficult prey as gyrosprinters can race at nearly twice that speed. Sometimes, its chases after prey can turn out unsuccessful. With heaving sides it will break off the hunt and trot to a halt; then it kneels down and rests in its squatted position. However, it does not always give up. It will often keep searching for prey, walking along and pinging occasionally while on a searching hunt. A rayback will end its chase for prey using its short, knifelike proboscis to slice a huge, crippling wound into the side of its prey. The prey animal, now trailing its entrails, will collapse in a cloud of dust. The triumphant rayback trots up to it and hunkers down to feed. This is accomplished by the liquivore inserting its tongue deep within its victim. Persistence can pay off for a hungry rayback.
Faster and more agile than an arrowtongue, the rayback can outsprint the arrowtongue and, as a result, can tackle prey such as low-feeding flyers, young herd animals or ambushed Gyrosprinters. Notable for its particularly unpleasant temper, raybacks will charge virtually anything that gets too near
Sometimes, however, they themselves can become prey to larger predators, such as Eosapiens.