Obligatory disclaimer: real life sucks. It is also tricky,
both on a lesser level – i.e., co-existing with your family during the lockdown
that cannot end because of various reasons, both of
COVID-19-(directly)-related, and of Trudeau vs. Trump related. There are simple
solutions, but no one likes them, and so the lockdown goes on, satisfying fewer
and fewer people, no matter how good (and/or righteous) are its’ initial reasons
were… What next?
Today, I want to talk about the otters, actually. To wit,
they are 13 existing species of aquatic or semi-aquatic mammals, which belong
to the Mustelid family, (aka the weasels and co.), but also – to their own
subfamily, the Lutrinae. And-?
…Starting with the good old reliable taxonomy, there are
about eight existing genera of otters, (that hold the aforementioned 13
existing species), and about twice as many extinct ones. As Mustelids, otters
are more closely related to wild dogs, bears, and raccoons, rather than cats,
hyenas, and mongooses. Their relationship with the pinnipeds – namely, seals,
sea lions and walruses – is more obscure, taxonomically speaking, but
ecologically? Otters and pinnipeds are two sides of the same coin… sort of.
Let us elaborate. The pinnipeds live in seas and oceans – as
a rule. They come in several shapes, and in different sizes, but most of them
are social, gregarious, noisy mammals that often are easy to spot on the
shoreline; in the water, they may not be as formidable as the more ancient and
derived cetaceans are, but they are still a force to be reckoned with; in one
of his TV shows, Sir David Attenborough showed a bearded seal actually
outmaneuver a killer whale, meaning that you don’t discount the seals just yet!
On the other hand, we have the otters. Aside from the
well-known sea otter, and the much more obscure – and smaller – marine otter of
South America, all otters live in freshwater bodies instead. They are social animals,
and playful ones, but their basic unit is a single-family group, whereas
pinnipeds – especially such big ones as the elephant seals, fur seals, and
walruses – have harems instead. Proportionally, otters tend to be shier and
less noisy and noticeable than the pinnipeds are; very often they are much less
active during the day than at night, dawn, or dusk; in part, this is because of
human pressure, but the biggest freshwater otters of them all – the giant
otters of South America, (aka Pteronura
brasiliensis), are freely active during the day instead, human pressure or
not. What else is there?
The other animals. The aforementioned giant otter of South
America is the most formidable of otters; family groups of these species were
shown killing caiman, (cousins of the crocodile, remember?), and driving away
jaguars, (though in the case of the latter, a safe, respectable distance was
maintained, and the jaguars were young and not fully-grown or experienced). Put
otherwise, as in most of them mammal societies, size and strength, multiplied
by numbers of family group matter. The giant otters are the biggest and most
social of the river otters, hence their also the bravest and the boldest. The
other freshwater otter species – not so much, they are much more demure and
tend to stay out of the way of such carnivores, as wolves, bears, and lynx, for
example, (in the Northern Hemisphere, both in North America and Eurasia).
…The sea otter stands apart, not unlike the giant otter of
South America; its’ closest relative – proportionally – is the spotted-necked
otter of sub-Saharan Africa, (Hydrictis
maculicollis), but the two animals don’t have much in common: the
spotted-necked otter is a ‘typical’ freshwater otter, while the sea otter
behaves more as the seals and pinnipeds do.
…There are freshwater seals – true, or earless, seals – in fast.
They are subspecies of ‘marine seals’, the only truly freshwater seal is the
Baikal seal, Pusa sibirica, and it is
one of the smallest seals, under 1.5 m in length. It exists in the Baikal Lake,
which is more of a freshwater sea, really, and is an exception that underlines
the rule. The case of the sea otter, which is really the only otter known to
most humans, that went into the sea, is the same. …The marine otter Lontra felina, a close relative of the
North American river otter, looks much more like the other otters rather than
like the sea otter. It behaves rather like the otters, instead of the sea otter
does too… but we became carried away.
To summarize: otters have appeared later in Earth’s history
than the pinnipeds did, and as such, they were unable to fully transition to
the sea, as the seals and their relatives did, except for two species, of which
only the sea otter can compete with the pinnipeds in the sea, ecologically
speaking, and even it has some caveats in regards to its’ ecology, it is a very
different mammal from the seals and etc.. On the other hand, they were able to
keep the pinnipeds out of fresh water – the subspecies/species of earless seals
that were able to make it there are found in places where river otters are
uncomfortable to exist; all of them are more terrestrial than the pinnipeds are…
Well, this is it for now. See you all soon!
No comments:
Post a Comment