North American River Otter
Jan. 2, 2011 at 10:02 p.m.
Updated Jan. 1, 2011 at 7:02 p.m.
By Judie Farnsworth
The energetic river otter may act like a party in a pond. Sliding, chasing, tossing and diving for rocks - they play more than most wild animals.
But, it's more than pure fun. The play helps build social bonds and sharpen hunting skills.
In reality, they're secretive; sleeping most of the day and active at night, dawn and dusk. Their cute faces contradict a fierce hunting instinct. Socially, they use avoidance rather than conflict.
River otters are members of the weasel family, but with a much better attitude. They live on land, inland waterways and coastal areas. Fish and crayfish are their main foods, but they also eat insects, reptiles, amphibians and birds.
Otters living in an area signal a healthy ecosystem. The foods they like only survive in clean environments.
They weigh up to 30 pounds. Thick fur keeps them warm and dry. They're expert swimmers. Valves in their ears and nostrils close, keeping water out, like built in ear and nose plugs. A membrane slides over and protects their eyes for underwater vision - like goggles. They have webbed hind toes and thick tails that work like rudders. Sensitive whiskers help find prey.
River otters can dive to 60 feet and hold their breath for more than four minutes. Barely making a ripple, they speed around in water at 6 mph.
On land, if there's snow or ice they can run and slide, reaching speeds of more than 15 mph.
The sense of smell is most important to river otters. Hearing is second. They make quite a few sounds. They communicate mostly with their noses, by smelling areas they mark with urine, feces or a musky fluid secreted by scent glands. Not a happy thing for people, but that's life if you're an otter.
Dens are built in river banks or in the burrows of other animals, like beavers or woodchucks. Hollow logs, river banks and rock formations might be used for resting. There may be several tunnels in a den. One entrance may be underwater and another above ground. A nesting chamber is well above the water and lined with grass, leaves, bark and moss.
The family is the basic river otter social group and usually consists of a female and her pups. Occasionally, a male will be with them and there may be helpers that are not related to any particular group. There can be groups of all bachelor males or young that have ventured out on their own.
Groups travel together, share a den and groom each other, but usually hunt singly and don't seem to have a particular leader.
River otters once thrived throughout much of the United States. They've been threatened by pollution, habitat destruction and over-hunting. Many states have actively worked to restore otters to their historic areas.
In Texas, they are believed to be making a comeback to the central part of the state after declining to only Eastern Texas.
Because of their secrecy, it's difficult to get accurate population counts.
Chances of seeing a river otter in the wild are slim, but you can see one when you visit The Texas Zoo. Visit often and be sure to contact the zoo for upcoming event information.
Judie Farnsworth is a long time volunteer at the Texas Zoo specializing in educational programs.