The short-eared dog (Atelocynus microtis) is found only in and around the Amazon rainforest. For decades, scientists had almost no firsthand information about this elusive species. It hides so well that even experienced Amazon researchers can go years without seeing one.

With its slender build and low posture, it resembles a jaguarundi more than a typical dog. Its ears are short and rounded, unlike the upright shape seen in foxes or wolves. It has a bushy tail and a thick, usually dark coat.

Individuals vary in color from coffee brown or charcoal gray to reddish gray, and some have even been described as bluish black. It has webbed toes that help it move through flooded forests and swim across rivers. While all dogs have some webbing between their toes, the short-eared dog’s is more developed and suited for aquatic life. Its eyes contain a reflective layer called the tapetum lucidum, which improves vision in low light.

It is the only species in its genus, Atelocynus, and belongs to a distinct branch of the canine family. Its closest living relative is the crab-eating fox, not the more similar-looking bush dog as once believed.

Its range spans Brazil, Peru, Bolivia, Colombia, and Ecuador, with most individuals found in the vast forests south of the Amazon River and east of the Andes.

They avoid open landscapes and steer clear of plantations or villages. These dogs rely on large, undisturbed tracts of forest, and their distribution is patchy. One of the few places where sightings are a bit more common is southeastern Peru, particularly in the Madre de Dios region. But even there, encountering one is rare.

Short-eared dogs don’t live in packs. Adults are typically alone and extremely shy. They do not follow a fixed daily rhythm. Some are active during the day, others at night. This flexibility likely helps them avoid predators and reduce competition. Camera traps have recorded them on the move and even swimming after dark.

Though solitary, they still communicate in subtle ways and come together briefly to mate and raise young. Males have a scent gland near the tail that releases a musky odor when alarmed. It is not as strong as a skunk’s, but it works as a warning.

Rather than digging their own dens, short-eared dogs often use burrows abandoned by giant armadillos. These ready-made shelters offer a cool, hidden place to rest or raise pups.

Though classified as a carnivore, the short-eared dog has a highly flexible diet. In one study from Peru, fish made up nearly 28 percent of its intake. It also feeds on crabs, small mammals like agoutis and marsupials, along with birds, frogs, lizards, and large insects. About 10 percent of its diet comes from fruit. Researchers have found seeds from Brazil nuts, palm fruits, and wild berries in its scat.

Jaguars, pumas, ocelots, and bush dogs all compete for similar prey, so the short-eared dog survives by eating whatever it can catch or scavenge. Jaguars and boa constrictors have also been known to hunt them.