Not long ago, in need of some quiet, I turned to the live
sea-otter cam maintained by Explore.org at the Monterey Bay Aquarium. All of
the otters living at Monterey Bay are rescues that for one reason or another
cannot be released into the wild, and watching them is always a peacefully
enjoyable time. As they glided about their watery habitat, it occurred to me
that I knew next to nothing about sea otters, and decided I wanted to learn
more. So, I learned a few things.
Like No Other Mammal In The Ocean
The scientific name for a sea otter is Enhydra lutris, which means, you will be staggered to know, “otter of the water” (perhaps Linnaeus was out of town that day). All otters are members of the family Mustelidae, making them cousins of weasels, badgers, and wolverines. Most sea otters spend their entire lives in the water – eating there, sleeping there, mating there, and even raising their pups there. They are able to pull this off because they have evolved attributes that separate them from all other oceangoing mammals.
Otters are the only marine mammals that capture prey with
their paws instead of by mouth. Their paws are somewhat oversized compared to
the rest of their bodies, and are lithe and very nimble; factors that make them
proficient hunters. So dexterous are their paws that they are able to do
something that many humans are incapable of: they can rub their bellies with
one paw while patting their heads with the other.
Their clever paws fulfill another important otter need:
Grooming. The fur of a sea otter is a marvel of evolution. It is so dense that,
despite living in the water, an otter’s skin almost never gets wet. More
importantly, because otters are the only sea mammals that do not have a layer
of blubber, it is that incredible fur (with some assistance from a very speedy
metabolism) that keeps an otter warm in its sometimes frigid home environments.
In order for its fur to do all of the things an otter needs it to do, it must
be kept in tip-top shape, and the only way to do that is by grooming. If a sea
otter is awake, and is not involved in swimming or eating, there is a high
probability that it is grooming its fur.
Another evolved trait that greatly aids in an otter’s ability
to locate and capture dinner (and to avoid becoming dinner itself) is its pair
of amazing eyes. Sea otters can see equally well above and beneath the surface,
because their lenses are specially adapted to the purpose. When they dive under
water their lenses are pushed outward through their pupils. This rounds the
lenses, enabling them to bend light more efficiently, effectively neutralizing the
constraints on bending imposed by water. Enhanced underwater vision is one of
the things that enables sea otters to be such efficient hunters. And make no
mistake, sea otters – cute or not – are deadly predators.
Their favorite things to eat are sea urchins, but they
also dine on mollusks, abalone, crabs, and occasionally fish. And they can be
picky eaters. In the wild otters have been observed taking a test nibble of whatever
critter they’ve brought to the surface, but then immediately throwing it back
and diving for something more toothsome. And in captivity they have shown a distinct
preference for shrimp and a thorough dislike of squid.
There are roughly 8.5 million animal species on our
little planet, and of those maybe 20 use tools. These include the great apes,
some monkeys, dolphins, crows and ravens, tuskfish and, of course, sea otters.
Everyone has seen videos of otters using their favorite tools – rocks – to
hammer opened the shell of a sea urchin or a clam. Sometimes they use two
rocks, placing a flat one on their chests where it acts as a sort of anvil. If
there aren’t any rocks to be had, though, otters are fully capable of
improvising, breaking open their dinner on some other handy solid surface – the
bottom of a boat, say, or the pilings beneath a dock.
Mating & Mothering
People who are averse to violence should absolutely avoid
watching sea otters mate. It is a vicious affair. A male otter, having selected
its preferred female, begins what looks far more like an assault than a courtship.
He strikes her with his paws, holds her underwater, and bites her nose. The
bites are so ghastly that they sometimes result in the female losing her nose
entirely. Male mating strategies are so ferocious that females have bled to
death or been drowned.
Female sea otters gestate for about six months, giving
birth to a single pup, or in very rare cases two. Pups are quickly weaned so
their mothers can begin schooling them in the finer points of catching their
own meals. Mothers teach their pups not only what’s good to eat, but how to
catch it, bring it to the surface, and how to use a rock to bash it open.
Without being able to observe and learn from their mothers young sea otters
would be completely unable to feed themselves and would quickly perish. Pups
are also taught how to secure a good napping spot by wrapping themselves in
strands of kelp, as well as how to groom their pelts into first-class shape.
Keystone Species
In their kelp forest habitats sea otters are apex
predators, and as such are absolutely vital to the continued health of their
local ecosystems. Without sea otters to prey upon them, sea urchins run
absolutely wild, reproducing like crazy and turning into swarms that can number
in the thousands. Urchins are herbivores with a particular fancy for the
tiniest of kelp plants, which they swarm upon, eating until there is no kelp
left.
In recent years, purple sea urchins have wreaked havoc on
kelp forests off the coast of California, leaving nothing behind except what
biologists call “purple carpets” or “urchin barons,” which are essentially
ocean dead zones. And what’s really strange, and not a little horrifying, is
that sea urchins can live for many months without eating, during which time
they are just sort of there, taking up space on the dead ocean floor, ready to
devour the first hint of returning kelp. Relationships of this type, between a
predatory species (sea otter), a herbivorous species (urchin), and plant species
(kelp) is known as a trophic cascade.
James Estes, a leading otter biologist, has analyzed the otter/urchin/kelp
trophic cascade and seems to have found evidence indicating that sea otters
influence the way in which carbon is transferred from the ocean, into the
atmosphere, and back into the ocean. Kelp, like all plants, sequesters CO2 –
gigatons of it – during photosynthesis, thereby neutralizing its effect on the
global climate. In a healthy kelp ecosystem, otters keep urchins in check,
which allows kelp to grow strong and do its job. In other words: No kelp = No
carbon segregation.
Extinction Events
Between the early 1700s and 1911, the relentless greed of
the global fur trade brought sea otters to within a hair’s breadth of
extinction. According to the best estimates, the global population of sea
otters prior to the fur trade numbered in the neighborhood of 3.6 million
animals. But by 1911, and the adoption of the International Fur Seal
Treaty (which included otters) that number had dropped to around 100,000.
The vast majority of sea otter pelts taken during the fur
trade years were sold at top dollar to wealthy people in China. (Because when
it comes to extinction it somehow always arrives at China.) And were not
talking about a couple of hunters, here. The sea otter trade was gigantic, and
it initiated equally gigantic changes around the world. Here’s Todd McLeish,
author of the excellent 2018 book Return
of the Sea Otter: The Story of the Animal That Defeated Extinction on the
Pacific Coast:
The animals thick pelt has led to
massive human changes: sea otter fur was directly responsible for the
establishment of a global mercantile industry, the alteration of Native
American cultures, the accusation that Russians enslaved at Native hunters, the
first use of firearms by Natives on the British Columbia coast, the first
Russian settlements on the Aleutian Islands, the deaths of hundreds (perhaps
thousands) of seamen from a half dozen countries, and the establishment of new
trade routes, not to mention the animal’s near extinction. All because of its
fur.
Over the years, various relocation programs have been
attempted, with the aim of reintroducing otters to their former habitats. Too
many of them, unfortunately, were unsuccessful, for a couple of reasons. First,
when the initial programs were undertaken in the 1960s, scientists didn’t know
nearly as much about otters as they do today. A better understanding of the
animals has led to relocation programs that have been conducted more slowly and
have been thought out in more detail beforehand. The second reason that those
original plans didn’t work has a great deal to do with governmental
incompetence. More often than not the last thing endangered animals require is
an overabundance of input from governmental bureaucrats.
Some relocations have been successful however. Every
single one of the sea otters living along the California coast are descendants of
a relative handful animals that were released off Big Sur in the 1980s. Similarly,
all of the otters along the Pacific coast of Alaska originated from six groups
of animals that were relocated from populations in the Aleutian Islands.
Today, otters are afforded some protection under the 1972
Marine Mammal Protection Act. The Act was signed into law by – hang onto your
hats – President Richard Nixon, who bowed to pressure from concerned citizens
and their elected officials. Nixon was a paranoid, delusional weirdo, and yet
insofar as the environment was concerned, he was – hang on to more of your hats
– way more rational than the gaggle of dangerous sociopaths currently
making up the GOP.
The aforementioned otters of California and around the
Aleutian Islands are considered to be endangered, so it’s illegal to kill them,
or to capture them for export outside the United States.
Sadly, there are scheming international groups that utilize
loopholes in the protective legislation. Otters are mainstays of zoos and
aquariums, and hunters who specialize in capturing them are driven by their
cupidity into locations where the animals are not considered endangered. In
those regions (notably the area around the Aleutians) hunters are able to, for
all intents and purposes, capture as many otters as they like, which they then
sell to overseas animal parks.
Yet another reason to empty the tanks.
Success!
The revitalization of sea otter populations is a major
ecological success story. Seriously. It’s huge. It happened through the actions
of committed citizens, people who value life apart from their own and who
understand or at least heed good science. They were able to communicate their
passion to politicians and laws got passed. That’s how to accomplish
environmental renewal.
It’s biophilia at work.
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