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Coypu: Myocastoridae

Behavior And Reproduction

Coypus are extremely passive and rarely aggressive. They are shy and fearful; the slightest disturbance will send them scurrying to the shelter of water, burrow, or other hiding places. Depending on their habitat, coypus are nocturnal, meaning they are most active at night, or crepuscular (kri-PUS-kyuh-lur), meaning they are most active at dawn and twilight.

Coypus are semi-aquatic, meaning they live both on land and in water. On land, they walk with slow, clumsy, awkward movements but if threatened, they can run fast and jump short distances. They are excellent swimmers and can remain submerged in water for more than ten minutes. Coypus can close their nostrils and lips behind their incisors while cutting vegetation under the water. The coypu is social and territorial, meaning it is protective of an area it considers home and claims exclusively for itself and its mate or family group. They live in groups of two to thirteen individuals, usually related female adults, their offspring, and one adult male. Young adult males usually live alone. Males and females have separate territories. The average home range is 6.1 acres (2.47 hectares) for females and 13.8 acres (5.68 hectares) for males.

Coypus sleep and nest in burrows, which range from a single, short tunnel, to multiple tunnels with small nesting chambers. Tunnels are often 50 feet (15 meters) or more in length. Above ground, they make raised beds of vegetation where they feed and groom.

Breeding occurs year-round and females have two or three litters per year. The gestation period, the time the females carry their young in the womb, is 127 to 139 days. The average litter size is six babies although it can range from one to thirteen. Coypus born in the summer reach sexual maturity at three to four months of age. For those born in the fall, it is reached at six or seven months of age. The average lifespan is less than one year in the wild. In a few cases under ideal conditions, coypus have lived for three to six years in the wild. However, in captivity, they can live for ten years.

WANTED: DEAD OR ALIVE

In 1938, about 20 coypus were imported into Louisiana from Argentina to be bred for their fur. But many escaped captivity and adapted well to the warm, wet climate and swampy habitat, breeding voraciously. They spread quickly to nearby states. As of 2004, there were an estimated twenty million coypus in the Louisiana. In 1998, it is estimated coypus destroyed 100,000 acres of swamp and marshland, posing a serious threat to many native species of birds, mammals, and amphibians. To combat the threat to the environment, the Louisiana Department of Wildlife and Fisheries received a $10 million, five-year federal grant to help eradicate, remove, coypus from the state. In 2002, the state began paying hunters $4 for each coypu they brought into state wildlife offices. Most are brought in dead but wildlife workers kill any that are trapped and brought in alive. In the first two weeks of the program, 9,000 coypus were killed. The goal is to kill 400,000 per year.

In the wild, coypus have many predators, including large snakes like the anaconda and boa constrictor, large cats such as ocelots and jaguars, red wolves, crocodiles, and otters.

Additional topics

Animal Life ResourceMammalsCoypu: Myocastoridae - Physical Characteristics, Geographic Range, Diet, Behavior And Reproduction, Coypus And People - HABITAT, CONSERVATION STATUS