river otters

River OttersLutra canadensis

Mustelid family

Aquatic mammals• 10-25 pounds• 30-40 inches long• + 12-15 inch tail• 10-20 years life span• Furred tail• Eyes protrude• 2 fur layers – • underfur 7 guard hairs, subcutaneous fat

Swimming• Underwater locomotion • Body• Feet & tail steering

• 4 minutes, ¼ mile• 7 miles/hour• Dive 50 feet• Best in water of all land mammals• Valves – seal ears & nose• Pulse rate drops• Slows blood & O2 circulation

Swimming

• Excellent hearing• Ok eyes on land• Great eyes under water• Keen sense smell• Whiskers – search for

food

Diet - carnivores• Fish• Minnows• Sunfish• Suckers• Carp• TroutAquatic plants/rootsCrunch thru shells

• Frogs• Turtles• Snails• Mussels• Crayfish• Snakes & eggs• Worms• Insects• muskrats

Teeth - 36• More teeth than any other mustelid in PA• 5 molars each side of upper and lower jaws• Only carnivore in PA w/ all these molars• Molars – perfect for crushing shells

Play• Wrestle• Slide• Sled• Sounds• Chirp, chitter, chuckles, grumbles• Screams– danger

• otters playing

• No hibernation• No food storage• Winter – water warmer

• River freeze• Swim under ice find air

pockets, dens

Dens• Lakes, rivers, streams, islands, marsh high ground• Under tree roots, rock piles, • Abandoned beaver, muskrat, or woodchuck burrows• Beaver lodges• Underwater entrance hole, living space above water,

several air or exit holes

Reproduction• Mature 2 years• Breed Jan – May in water• Delayed implantation (Dec, Jan, Feb)• 2 months gestation• 1 – 5 young• Males polygamous

Babies• Born April or May• Blind & toothless• Blind 5 weeks• Den until 3 – 4 months old• Learn to swim with mom

Pennsylvania

• Protected since 1952• No hunting, no trapping• Restocking since 1980’s• Water Pollution & strip mine runoff- improved conditions• Population size?

• Secretive• Nocturnal• Most in NE PA

• NY & MD – high pops & trapping legal

Keystone species• Clean water• Habitat provides for needs of many other species

• Opportunistic feeders• Habitat loss & water pollution• Avoid humans• Top of food chain• Social• Playful

Important questions ???• How are otters designed for life in the water?• Why is clean water important to otters?• Why is it difficult to know the otter population in PA?• Are otters active in winter or do they hibernate?• Carnivores or herbivores?• Diurnal or nocturnal?• How can river otters guarantee that offspring will be born in the spring?• Describe how an otter swims.• When was restocking of otters introduced in PA?• What family do otters belong to?• How many teeth do they have?