Many a zoo guest has delighted in watching the river otters swim, frolic and play as they glide effortlessly through the water. They look so friendly and cuddly. While it’s true, they have a lot of personality, beware to those who get too close. Their teeth and claws are wicked sharp and they know how to use them. When it comes to mating, it’s not always love at first sight. Dating can be kind of rough, even brutal.
In zoos accredited by the Association of Zoos and Aquariums, species populations are managed through the Species Survival Plan (SSP). They make decisions about animal moves and breeding recommendations to ensure the sustainability of a healthy, genetically diverse, and demographically varied zoo animal population.
That is how Thomas came to Pueblo. He was recommended to breed with our female, Freyja. Though young, she was already an experienced mom having bred with one of our older male otters, Thor or Odin. Perhaps we should have gotten a clue by Thomas’ original name, “TNT, because sparks flew when he arrived, and not in a love-filled, affectionate way. Both animals have very dominant personalities and neither wanted to give in to the other. When zookeepers introduced them for the first time, the wrestling match was on. Keepers let them wrangle for dominance as long as they thought it was safe and ultimately separated them to give them a break. They spent much of the first few days screaming at each other. Later introduction attempts were not much more successful. Their keepers are hopeful that when breeding season comes around in February, their breeding instincts will overpower their dominance issues and they will come together. For now the two girls, Freyja, Thelma and Thomas rotate through the on and off exhibit areas to alternate spaces while keeping in proximity to encourage familiarity.
By Anne Casey
North American River Otter
Scientific name: Lontra canadensis
Common name: North American River Otter
Description: The body of the otter is long, sleek, and streamlined - built for swimming. Otters grow to five feet in length from their nose to the end of their flat tapered tail and can weigh from 11 to 33 pounds. Their legs are short and their feet are webbed. When swimming they paddle with their back feet and move their powerful tail up and down propelling themselves through the water at speeds of up to 7 mph. Their faces are broad and covered in sensitive whiskers that help them locate fish. Their coats are generally brown to black on top and lighter below. There are several regional subspecies with subtle color variations. They have a thick, warm undercoat covered by sleek outer guard hairs that capture a layer of insulating air, keeping them warm in the coldest water.
Range: Otters can be found all over North America from the Gulf of Mexico to northern Alaska and from the Pacific Ocean to the Atlantic Ocean.
Habitat: Due to their aquatic lifestyle otters are always found near permanent water features. They can use many different aquatic environments including rivers, lakes, swamps and coastal waters.
Behavior: Otters are carnivores and consume mostly fish, but also supplement their diets with amphibians, crustaceans, and occasionally birds, reptiles, mollusks, small mammals and fruit. They live in riverside burrows, hollows in trees near the water’s edge, or abandoned beaver lodges. They are sometimes solitary, but can also live communally in groups of several males or a female and her offspring. They are not territorial and will not defend home ranges, but they do mark with feces, urine and scent glands to make their presence known. Vocalizations include a low chuckling noise and a loud snort that indicates danger.
Reproduction and rearing: Breeding occurs in the late winter or early spring. The otter is unique in that, after mating, the fertilized egg can delay implantation for up to 8 months, depending on environmental conditions. Once implanted the gestation period is 60 – 63 days. Litters can be as large as five cubs which the female cares for exclusively. Otter cubs nurse for 3 – 4 months and stay with their mother until they are 10 months old.
Predators: Due to their speed and agility in the water the otter has very few aquatic predators with the occasional exception of alligators, American crocodiles and killer whales. On land, however, they are prey for bobcats, cougars, coyotes, dogs and wolves.
Lifespan: In captivity otters can live up to 25 years. In the wild they live to about 13 years.
Conservation Status: The IUCN Redlist rating for the otter is Least Concern due to their widespread distribution throughout their range. Water quality improvements following clean water regulations have allowed them to reclaim some of their historic territory.
References: http://oldredlist.iucnredlist.org/details/12302/0, http://www.arkive.org/north-american-otter/lontra-canadensis/image-G65462.html