The bat-eared hoek (sometimes also called a ren) is a fleet-footed didelphid completely adapted to the arid environment of Spec's southwestern North America. This small nocturnal carnivore hunts for small lizards and snakes, burrowing beetles, spiders, scorpions and other invertebrates. The bat-eared hoek has a relatively good night vision, but this is nothing compared to its acute hearing. They can hear their prey moving beneath the sand from many meters away, and are claimed to be able to sense even the hearbeats of a still-lying animal.

    Bat-eared hoeks are solitary animals, and when the paths of two hoeks cross, results may be rather violent. A cornered hoek can also defend itself very aggressively, and many a scientist has had the displeasure of proving the glove-pearcing sharpness of its teeth. When threatened, the hoek usually makes loud barking noises, which are said to resemble the sound of an asthmatic chihuahua. (The name "hoek" is in fact an onomatopoetic reference to the animal's bark.)