Things you otter know

Flamingo Gardens’ otter display in Davie FL

Last week’s blog about Peace River Wildlife Center’s river otter patients raised many questions.  Quite a few people were unaware that otters are found in Florida, and other readers were curious about the habits and habitats of this adorable species.

North American river otters have long slender bodies, short legs, and webbed feet.  Their thick, short fur is very dense to help conserve heat when in water, but they still require a high metabolic rate to maintain their proper body temperature.  They eat 15% of their weight daily to fuel that furnace.  (That’s the equivalent of 30 pounds of food for a 200-pound person.  I could eat that many crab legs but would have a difficult time trying to eat that much broccoli in one sitting.)

From Mexica to Canada, otters are found primarily in areas of fresh water, but will live in brackish or coastal zones also.  Some of Port Charlotte’s and Punta Gorda’s brackish natural canals are frequently visited by otters, and they are occasionally spotted near the Harbor’s mangrove shorelines.  They are partial to clean, unpolluted waterways and locations far away from the commotion of people.  They are found throughout Florida except for the Keys, but they are shy creatures and are seldom seen except by quiet kayakers.

Southwest Florida, with its abundance of creeks, swamps, and ponds, is a great place for this member of the weasel family to live.  Mating season here is in the fall and winter, with a gestational period of about 60 days.  Interestingly a pregnancy can last over a year due to delayed implantation of the fertilized eggs (called diapause), which helps to ensure the offspring are born during the most favorable conditions possible.

A typical litter will consist of 1-3 pups (sometimes called kits or kittens.)  They are born in a den that the mother has dug or commandeered from another animal, in the bank of a river, creek, or pond.  Burrows, where otters relax while not in the water, may be dug into the side of river banks or under a fallen tree or root near the water’s edge.

The otter display at Tampa’s Lowery Park Zoo

The babies are born fully furred.  Their eyes and ears open at four weeks, and they are weaned by three months.  The father is usually chased off until the babies are weaned, at which time he may return to help raise the family.

While youngsters are naturally able to swim, mother must persuade them to enter the water at first.  At two months the babies are introduced to the water, sometimes clinging to mother’s back until they are proficient swimmers.  The juveniles stay with mother for the first year, reaching sexual maturity at two years of age.  She will teach them to hunt and find shelter.

River otters are carnivores that prey on mostly aquatic organisms: Fish, frogs, clams, small turtles, etc.  They have also been observed eating small mammals and occasionally even birds.

Reaching a length of 3 to 5 feet, the adults are well-muscled and weigh from 10 to 30 pounds.  The males are 30% larger and heavier then the females.  The tail is 40% of total body length and facilitates their strong swimming skills.  Otters can swim 8 mph and dive up to 36 feet, though few Florida waterways have such depths.

Unlike many specialized animals that are adapted to water and clumsy on land, otters can run quite wel also, up to 18 mph.  They have a distinctive loping gait but are remarkably agile.

River otters’ life expectancy in the wild is up to 10 years, and they can live more then 20 years in captivity.  They are trapped for their warm waterproof pelts, but the main threat to their numbers is from habitat destruction or fragmentation and pollution.

Stock photo of an otter den in a deep bank.

When Europeans first arrived in North America, river otters were abundant across the continent from the Rio Grande north to Alaska, missing only in the desert states.  By the 1980s there were 26 states in which otters were rare or extinct.  Conservation and reintroduction projects have decreased that number to 15.

This species is a top predator and vital for the health of the ecosystems where they live.  In case you need another reason to protect this species, try watching them in the wild (or at your nearest zoo’s breeding program) while they frolic and cavort.  If that doesn’t put a smile on your lips, there’s something wrong with your face.

by- Robin Jenkins, DVM