Because of their playful and curious
attitudes, sea otters are often a favorite of marine mammal
lovers. Recognized by their rounded heads, small eyes, and
visible, pinched ears, sea otters are the largest member of
the weasel family.
Other than the river otter, they are
also the smallest marine mammal, with an average length of
four to six feet and weight of sixty to one hundred pounds.
Feeding and Behavior
Sea otters are best known for their
luxurious fur coats that keep them warm and buoyant; at
15,500 hairs per square inch they have thicker fur than any
other mammal. Such a coat paired with a high metabolic rate
allows them to thrive without the layer of blubber that most
marine mammals require. Their high metabolism enables them
to eat about 25% of their weight in food every day. While
their main diet consists of clams, sea urchins, and abalone,
otters eat over 150 species – whatever is abundant in area.
Such consumption has led sea otters to be recognized as a
keystone species –the presence or absence of the otters
greatly affects the surrounding ecosystem.
Sea otters spend most of their life
within one mile of shore; their movement on land is slow and
limited, causing them to only come out of the water during
rough storms. They reside in near-shore rocky, coastal
environments, relying on kelp, or in soft-bottomed estuaries
where prey is abundant. Otters are solitary hunters, often
staying in small groups or alone. Their average dives to
retrieve food are in water less than 100ft deep, but dives
up to 975ft have been recorded. Flaps of skin in their
underarms allow them to store food and hunt for longer
periods of time. After diving, Sea otters will float on
their backs to eat, using rocks as anvils to smash the
shells of their prey.
Originally, sea otters were said to
have ranged from Baja California, up the coast, and along
the Aleutian Chain to Japan. Reportedly discovered in 1741,
Sea Otters were very abundant throughout this area,
estimating at 800,000 in the population. Extreme hunting for
pelts, however, killed about one million sea otters in just
170 years, bringing the species almost to extinction. In
1911 a treaty between Russia, the United States, Japan, and
Great Britain was made to protect sea otters and Northern
Fur Seals (combined, these were the two most prized North
Pacific fur-bearing marine mammal species hunted very
competitively in the early 19th century by
Russia, America, Britain and others). The population of
otters has slowly recovered to a modern estimate of about
107,000, due in part to several relocation efforts. Today
sea otters are found in patches, ranging from Central
California to the Aleutian Islands. Without the threat of
hunting, oil spills are one of the biggest dangers to sea
otter recovery, as well as entanglement with fishing gear,
other pollutants, and climate change.
While the individual rogue sea otter
has been sited near the Fort Ross area, the original mass
has not yet returned to this region. With present
conservation efforts and a recovering population, however,
we remain hopeful that sea otters will once again be seen
off the coast at Fort Ross.
Sarah G., Joseph Mortenson, and Sophie Webb. "Sea Otter." Field
Guide to Marine Mammals of the Pacific Coast: Baja,
California, Oregon, Washington, British Columbia.
Berkeley: University of California, 2011. 454-68. Print.
Marine Mammal Center:. N.p., n.d. Web. 06 Oct. 2013.