Pacarana: Dinomyidae

Because most pacarana behavior has been studied among captive animals, biologists know little about how these animals act in the wild. However, we do know that they are active mostly at night, when they spend most of their time in solitary searches for food. They occasionally climb trees to get to food sources, but spend most of their time on the ground, sitting up on their haunches to manipulate food with their forelimbs. They do not seem to dig, despite their sturdy claws. Although their Latin name indicates a placid nature and slow-moving ways, pacaranas are well equipped to defend themselves and have a strong will to do so. They can be surprisingly vicious in attacks on interlopers and predators, animals that hunt them for food, alike, including pet dogs and other pacaranas. They can climb well and walk on two feet occasionally for various purposes. Adults often live alone, but have also been observed cohabitating in pairs and family groups. Their communication with each other is fairly sophisticated and features seven different sounds, including singing, hissing, tooth chattering, stamping their front feet, and whining.

Pacaranas make a sound like crying to attract mating partners, and then engage in an elaborate courtship ritual during the breeding season in about November through January. The ritual has been described as a mixture of dancing and wrestling, with much sniffing, growling, and whimpering as a male and female stand on their hind legs to grapple with each other and interlock their front cutting teeth. Head-tossing is common prior to the male mounting the female, which he does after approaching her with dramatically trembling legs. Females gestate, or experience pregnancy, for about 222 to 283 days and can be quite aggressive during the pregnancy. Scientists have never observed pacaranas building nests. Litter sizes are usually one or two pups, each of which weighs about 32 ounces (900 grams). Young can move around independently almost immediately and are born with eyes open and fully furred.