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North American River Otter

Lontra canadensis

Origin: North America

  • Found in and along waterways and coasts

Size: Adults can weigh between 11 and 30 lbs. Males tend to be 5% larger than females.

Lifespan: In captivity they can live up to 21 years, and in the wild 8-9 years

Diet: Carnivorous

  • Fish are the primary part of their diet

  • They eat crustaceans, aquatic insects, small mammals, reptiles, amphibians, birds, and mollusks

Activity: Generally nocturnal


  • Breeding season is from December to April.

  • Female estrus lasts about a month per year, and true gestation lasts 61 days.

  • River otters delay implantation up to eight months

  • Young are born between February and April. Birthing process can take three to eight hours

  • Litter size can be up to five pups but tends to average three pups

  • Otter pups are weaned at 12 weeks and they reach adult weight at 3-4 years of age

  • Females raise the young alone.

  • Mothers intorduce the pups to water at two months of age

  • Otters often operate as family units with mothers and offspring and sometimes fathers as well

  • Yearlings will venture out in search of new territories. Females tend to travel farther away than males. Females are more territorial than males.

  • Many young males will establish male groups

Extra Facts:

  • Otters and beavers are sympatic; often beavers and otters share the same ponds or streams

  • Most social out all the Mustelids

  • Communicate through smells and sounds

  • The river otter is a semi aquatic mammal, they establish a burrow close to the waters edge. They spend 2/3 of the time on land.

  • The den usually has many tunnel openings, One of which allows the otter to enter and exit the water 

  • Their right lung is larger than their left, Having four lobes compared with two for the left. It is believed to be adaptive for underwater swimming. 

  • River otters have 36 teeth

  • They can consume 1 to 1.5 kg (2.2 to 3.3 lbs) of fish per day

  • River otters can travel up to 26 miles in one day

  • They can swim at speeds of up to 6 mph and dive to depths of 60 ft

River Otter vs Sea Otter:

  • River otters swim belly down most of the time, while sea otters float on their backs.

  • Sea otters are two to three times bigger than river otters.

  • River otters' tails are long and pointed. Sea otters' tails are short and flat.

  • Sea otters spend much of their time in water, while river otters spend more of their time on land.


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