North American River Otter
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Lontra canadensis
Origin: North America
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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
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Fish are the primary part of their diet
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They eat crustaceans, aquatic insects, small mammals, reptiles, amphibians, birds, and mollusks
Activity: Generally nocturnal
Reproduction:
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Breeding season is from December to April.
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Female estrus lasts about a month per year, and true gestation lasts 61 days.
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River otters delay implantation up to eight months
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Young are born between February and April. Birthing process can take three to eight hours
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Litter size can be up to five pups but tends to average three pups
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Otter pups are weaned at 12 weeks and they reach adult weight at 3-4 years of age
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Females raise the young alone.
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Mothers intorduce the pups to water at two months of age
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Otters often operate as family units with mothers and offspring and sometimes fathers as well
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Yearlings will venture out in search of new territories. Females tend to travel farther away than males. Females are more territorial than males.
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Many young males will establish male groups
Extra Facts:
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Otters and beavers are sympatic; often beavers and otters share the same ponds or streams
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Most social out all the Mustelids
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Communicate through smells and sounds
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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.
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The den usually has many tunnel openings, One of which allows the otter to enter and exit the water
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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.
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River otters have 36 teeth
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They can consume 1 to 1.5 kg (2.2 to 3.3 lbs) of fish per day
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River otters can travel up to 26 miles in one day
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They can swim at speeds of up to 6 mph and dive to depths of 60 ft
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River Otter vs Sea Otter:
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River otters swim belly down most of the time, while sea otters float on their backs.
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Sea otters are two to three times bigger than river otters.
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River otters' tails are long and pointed. Sea otters' tails are short and flat.
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Sea otters spend much of their time in water, while river otters spend more of their time on land.