The pacarana (Dinomys branickii) is a rare and slow-moving nocturnal rodent which inhabits the forests of the western Amazon basin and the cloud forest environment of the eastern Andes. In addition to the forests of Peru, including those accessed from Cusco, the pacarana is found in northwestern Venezuela, Colombia and the lowland and mountain forests of western Bolivia.
One of the strangest animals it is possible to see in the Tambopata National Reserve, the pacarana is descended from the truly gigantic prehistoric rodents that once roamed the forests of South America some forty million years ago. Today, it is the world’s third largest rodent, after the South American capybara and the North American beaver. It can measure up to one meter in length and weigh as much as fifteen kilograms (over 30 pounds). With its small eyes, short ears and blunt snout, the pacarana looks like a giant guinea pig. Its dark brown, almost black fur is flecked by two rows of white markings that run along the entire length of its back.
This species is so uncommon that until quite recently very little was known about its biology, and it remains virtually unstudied. Although scientists have known since its discovery in Peru in 1873 that the pacarana has a large range, examples of the species are very rarely sighted. Traditionally, they were hunted by indigenous people for their meat, and their slow-moving nature made them easy prey. When pacaranas are spotted in the wild, they tend to be seen in family groups of four or five individuals.
Fascinatingly those pacaranas which have been captured and confined in zoos have shown themselves to be more than slow moving; they have proved to be so curious and willing to approach humans when kept in captivity, even rubbing themselves against people’s legs, that their behavior has been compared to that of domestic cats.
In the wild, they roam the forest floor at night, moving slowly and ponderously and relying on their senses of smell, taste and touch to compensate for their poor eyesight as they search for the shoots, fruits and leaves they tend to eat. When feeding, the pacarana behaves like a squirrel, using its front paws to skillfully manipulate its catch, while sitting erect on its hind legs.
In addition to indigenous human groups, the pacarana is also hunted by the Amazon forest’s other predators, including ocelots. When threatened, the pacarana will rely upon the long claws of its front paws for defense, a tool which it usually employs for digging.