Sea Otters! (Enhydra lutris)

Order and Family

Order Carnivora, Family Mustellidae

characteristics

long skull

short rostrum

5 toes on each foot with non-retractable claws

anal glands well developed

carnassials are adapted for crushing shellfish

30-100 lbs

swim with strong flattened tails and wide, webbed hind feet.

 They lack blubber or large fat stores and instead keep themselves warm by dense fur, high metabolic rate, and counter current systems.

diet

urchins, abalone, bivalves, crabs, barnacles & other crustaceans, squid, stars, fish.  

They use stones as tools.

 They find benthic food by feeling with front feet and also use their vibrissae.

coat

Each guard hair is surrounded by 60-80 undercoat hairs forming a bundle.

have 700,000 hairs per square inch, which is 2 times as many as river otters.

It is the densest fur of all animals.

Tips of guard hairs are flat & with the lack of erectile muscles, the coat remains flat and compact.

need to groom every inch of the coat, squeezing water out with their paws, spreading oils and blowing air into it.  

oils keep the coat streamlined and waterproofed.

their skin is loose and 1.5 times their length

Grooming occupies 5-11% of their time.

digestive system

to keep metabolism high otters eat more than 25-30% of their body weight

digestive system is 10x their body length to accomplish this

Sensory systems

see well in and out of water by changing the shape of their eye lenses

females can recognize pups by smell and calls

males can smell a female in estrus more than a mile away

diving adaptation

Large amounts of hemoglobin in blood and myoglobin in muscles.

Females forage at 50 or so feet.

Males may forage deeper at 80 feet.

Both can dive much deeper >100 feet.

Dives typically < 5-8 minutes.

Osmoregulation

75% of their water needs come from their diet and they drink sea water for the rest.

Their kidneys are twice those of river otters and 2% of body weight, from which they produce a concentrated urine.  

life span

about 15-20 years

females usually longer than males

females mature 3-4, males around 5 years

social behavior varies by location

otters from Alaska and Siberia are much larger than California otters and spend more time in water

reproduction

off Alaska and Siberia breeding is june-july, pups born may-june

off California breeding is july-october, pups born jan-march

males bite the nose of females stimulating ovulation

delayed implantation

mother provides care and training for five months (grooming, diving, hunting)