They might be one of the smallest marine
mammals, but they also have a disproportionately large influence on
one of Earth’s most productive ecosystems. this is Mike Fitz with
explore.org and here are five fascinating facts about sea otters and
the kelp forests they call home. If you know someone who spends a lot of
time styling their hair, it probably doesn’t compare to the work sea otters
put into theirs. Unlike seals and whales, sea otters lack
an insulating layer of blubber to keep them warm. Instead, they rely on their
thick fur. Sea otter fur is incredibly dense — as many as 1 million hairs grow
per square inch — but it needs to be kept meticulously clean to maintain its
insulating properties. Otters spend several hours per day grooming their fur
to maintain a dry insulating layer between the cold ocean and their skin.
Grooming also entraps air within the fur to increase the animal’s buoyancy.
Sea otters don’t groom for style it is an act vital to their survival. Even with their fur to keep them warm
sea otters are hungry critters. They maintain a relatively high metabolism
and need to eat about 25% of their body weight in food each day.
Imagine an 80 pound child eating 20 pounds of meat every single day.
That’s what otters must do to remain warm and active. With teeth designed for
crushing shells and long sensitive whiskers to help them locate prey, sea
otters are well adapted to hunt invertebrates such as clams, crabs,
mussels, urchins and worms. They also use rocks to dislodge prey from the seafloor and hammer open hard shells to access the meat inside. If you’re a clam or
urchin under these circumstances, sea otters are anything but cute. They are
skilled and hungry predators. A vast algal forest grows in the shallow
waters hugging the North Pacific coastline. The habitat is dominated by
many species of kelp. Under optimal conditions some species of kelp can grow
dozens of feet per year. Kelp are the major primary producers of energy in coastal marine ecosystems of the North Pacific. Like trees on land, kelp forests
provide both home and pantry for a diverse array of species. Kelp forests dampen the force of waves, a fact sea otters know well. When not foraging they frequently wrap themselves in kelp blades to keep from drifting away. Sea
urchins are fond of kelp too but for a different reason. They eat it. In areas
where urchins grow abundant enough, they can over graze a kelp forest like too
many sheep in a pasture, resulting in a habitat known as an urchin barren. This
habitat can persist indefinitely. they are also relatively unproductive
environments compared to those with large stands of kelp. Otters and other
predators like sea stars help keep sea urchin populations in check,
allowing kelp forests to thrive. People hunted sea otters to near
extinction in the early 20th century. In many areas the catastrophic loss of sea otters allowed sea urchins and urchin barrens to proliferate. By the time sea
otter populations recovered in the outermost islands of the Aleutian chain,
it was too late for the Steller’s sea cow. Related to manatees and dugongs, the
Steller’s sea cow lived in kelp forests in the Commander Islands, one of the most remote corners of the North Pacific. When the fur trade decimated otter
populations around Bering Island, urchin populations likely exploded. This would
have led to a great decline in kelp, which was the sea cow’s primary food.
Around the time otters were extirpated from this area, the sea cow went extinct.
While overhunting of Steller’s sea cow played a significant role in their
demise, some scientists hypothesize even if humans had not hunted sea cows the
loss of otters alone and the resulting proliferation of sea urchins would have
caused a cascade of effects leading to the sea cows extinction. As John Muir wrote so eloquently, when we try to pick out anything by itself, we find it hitched to everything else in the Universe. And so it is with sea otters,
sea urchins, and kelp forests. Sea otters are supremely adapted to
their environment and their work ripples throughout their aquatic ecosystem. If you enjoyed this video, please comment, like and subscribe. This is Mike Fitz
with explore.org, never stop learning.