Neotropical River Otters
Last Updated: May 17, 2012
Playful snorts, whistles and screeches erupt from the riverbank, where muddy waterslides cut a path through vegetation and empty into fresh waters. The squeals come from Neotropical river otters, a playful species that loves to toboggan both solo and in unison.
Scientific Name: Lontra longicaudis
Status in the Wild: Threatened
Habitat: Marshes, Rivers, Swamps
River otters are diurnal and nocturnal, meaning they are active both at night and by day. They can weigh up to 20 pounds measure approximately two feet from their head to tail, which tapers from flat and broad to a thin tip. Neotropical river otters have two layers of smooth, thick fur: their brown outer layer of guard hairs is thick and oily, providing waterproof protection of the under layer, which traps air and provides insulation even in the coolest river waters.
Skilled fishermen, river otters forage for fish and other preferred foods underwater, where they can hold their breath for up to eight minutes. Researchers believe that this species consumes an incredible 15-20% of its body weight each day, or two to four pounds per day, per animal. Their preferred diet includes mollusks, fish, aquatic invertebrates and crustaceans such as shrimp, crayfish and crabs; they are also known to hunt aquatic birds.
Neotropical river otters live from Mexico south through Peru and Uruguay, from sea level to 10,000 feet in altitude. Though they range throughout Costa Rica, except on the highest mountaintops, these aquatic mammals are considered uncommon to rare within national boundaries.
True to their name, Neotropical river otters live near rivers and waterways. They den in natural structures, such as caves, or shallow self-made shelters no deeper than 20 inches. Interestingly, while most otter species construct dens with at least one underwater point of entry, research into Neotropical river otter shelters has revealed no such entrance.
In general, the territory for female river otters can stretch from 4 to 50 miles of riverfront; males have slightly larger, non-overlapping ranges. In some areas, hierarchy determines male territories, and the most dominant animals occupy the largest and most prime stretches of river frontage. In Costa Rica, Neotropical river otters are found along most major rivers including the Sarapiqui, Puerto Viejo, Sierpe, Tempisque and Tortuguero.
Neotropical river otter reproduction has not been studied extensively. Scientists believe that animals in the northern range, including Costa Rica, mate during the end of the breeding season. Northern range female river otters save their fertilized eggs, delaying implantation until the following mating season.
Gestation lasts approximately two months, and litters can number from one to five pups. Mother Neotropical river otters teach their young to swim immediately; males participate in this training on occasion. Otter pups typically nurse from three to four months, and are independent between eight months and one year of age. They will reach sexual maturity by three years, and can live for up to 23 years in captivity.
Status in the Wild:
There is not enough data to determine the conservation status of Neotropical river otters. However, this species is the unfortunate victim of pelt hunters, who in Peru and Colombia alone killed a reported 30,000 annually during the 1970's. In recent years, the fur trade has declined but habitat destruction has increased, making this species extinct in some areas and very rare in others.