Have you ever taken a hike along a river in the winter and noticed markings that look as though someone was trying to send a message with a special code? You see a dot-dash dot pattern in the snow above the riverbank. When you pull out your trusty field guide of mammal tracks to see if there is anything that matches the pattern, you discover that yes, just as you hoped, it is the sign of a river otter.
The river otter is about three to four feet long and weighs between fifteen to twenty-five pounds. Its long tail is thicker close to its body and slims down to a point, making up one-third of the total body length. Rich brown fur covers most of the animal. A tan underside is topped off with silver-gray fur on the throat. The long whiskers are used for finding underwater food.
River otters feed on smaller, slower-moving animals that live in the water. Much of their diet consists of medium-sized fish, but they also enjoy crayfish and frogs.
River otters make their homes around marshes, sloughs, ponds, lakes, and streams. For protection, they tend to use natural structures such as logjams, overhanging rocks and abandoned shelters built by other animals like the beaver. Following their reintroduction to the state in the late 1990s, they are now found in several watersheds in Indiana.
Female otters are ready to have pups when they reach the age of two years. Males may take longer to reach sexual maturity. Mating peaks in March and April, and young arrive the following spring. The birth is delayed for nine months, with the actual development of the young lasting 60 days. There are usually 2-3 pups born and the young are able to fend for themselves within six months, but they will remain with the mother until she has another litter.
River otters usually can live in the wild for 10-15 years unless they encounter hazards such as wandering to close to roadways or accidentally being trapped.