River Otters are semi-aquatic, slender, long-bodied mammals which are specialized for capturing prey in the water. Otters have a long muscular tail, short stout legs and thick oiled fur. Small rounded ears and nostrils close when the otter is underwater. In Florida, river otters weigh 11 to 31 lbs. and males are larger than females. River otters forage alone or in pairs. They are active during the day and at night, hunting in streams, rivers and ponds for fish, crayfish and turtles. Otters have a high metabolic rate, an adaptation for living in an aquatic environment where body heat is rapidly lost. They need to eat 15% of their body weight a day. Although otters always remain in or near the water, they spend their inactive time in burrows dug into riverbanks or at other rest sites on land. Dens are located in shelters dug by other animals or natural hollows. Otters breed once a year and in Florida mating occurs in fall and winter. Though the embryos develop for about 8 weeks. Litters usually consist of 2-4 kits, which are born fully furred. The young open their eyes after a month and are weaned at three months. They travel and feed with their mother until they are about a year old.