What are the most interesting seals?
The seal family might seem rather homogeneous at first glance, but if you take a closer look at its various species it becomes a lot more diverse. Here are the ones which stand out the most, to me at least.
Leopard seals. This one’s an obvious choice. The third largest seals in the world (at up to 600 kg), they are easily recognized by their massive, reptilian head and muscular body. What really distinguishes them is their diet.
They are the only “macropredatory” seals, feeding on large animals such as seabirds, penguins, and other seals – even young elephant seals! Ironically, they sometimes also feed on microscopic krill. The leopard seal is the only seal species known to have killed a human (a British scientist, in 2003).
Elephant seals. There are two species of elephant seal – one in southern waters, the other on North America’s Pacific coast. The former is actually the world’s largest carnivoran, with the largest males weighing in around 4,000 kilograms. Females are much smaller, as both species are highly sexually dimorphic.
The males also possess a large, trunk-like proboscis which has the incredible function of recycling the moisture which they exhale; it’s like a biological version of the Fremen stillsuits in Dune. Southern elephant seals are also the deepest-diving seals, sometimes venturing more than 1.5 km below the surface.
Hooded seals. The males of this strange Antarctic species have a bulbous, hollow bladder which hangs above their eyes, vaguely similar to an elephant seal proboscis. This “hood” is what gives them their name.
Even more bizarre, however, is their rather grotesque ability to inflate a blood-red membranous balloon from one nostril. Both the hood and the membrane are sexual selection characteristics which make the males more attractive. The pups are also unique in that they have a bluish-silver colouration.
Monk seals. These guys are interesting in that they’re the only seals which inhabit tropical climates. One species is found in Hawaii while the other lives in the Mediterranean Sea, as well as off the coast of northwest Africa. There was once another species in the Caribbean, but it died out in the 1950s.
Extinction is sadly a real threat to the two remaining species. Both are endangered, with the Mediterranean monk seal only having a few reported sightings each year. They get their name from the folds of skin on their neck, which vaguely echo the cowl of a monk.
Baikal seals. Another easy pick. Also known as the nerpa, the Baikal seal is a truly fascinating species endemic to Baikal, a vast rift valley lake in Siberia. The lake as a whole is super interesting, which is why I wrote a whole answer on it. It’s thousands of kilometres away from the ocean, so how seals got there is quite mysterious.
In any case, Baikal seals are the only exclusively freshwater pinniped species in the world. They’re also the world’s smallest living pinnipeds, averaging at a metre or so in length, and have a marvellously spherical shape. They feed primarily on golomyankas, a very bizarre fish which is also endemic to the lake.
Crabeater seals. The world’s most abundant seals, crabeaters have perhaps the most unique diet of any species in the family – although, confusingly enough, they don’t eat crabs. Rather, they’re specialized to feed on microscopic krill, and the way in which they do that is fascinating.
Each crabeater seal tooth has five long, spindly cusps which interlock with the other teeth. The result is that when the seal swims with its mouth closed, its dentition forms a perfect sieve with which to filter krill from the water. It’s almost like a rudimentary form of baleen.
So, those are my top six. However, I’ve got a handful of honourable mentions which I couldn’t resist briefly adding. They are as follows…
- Other freshwater seals. Some otherwise marine species have lake-dwelling populations. Examples include Finland’s Saimaa seals, Russia’s Ladoga seals (both ringed seal subspecies) and the harbour seals which inhabit lakes in Alaska and Canada.
- Ribbon seals, an Arctic seal species with a striking fur pattern. Their contrasting white rings on a black background are especially pronounced in males.
- Ross seals, Antarctica’s smallest and rarest seals. They have a thick neck, huge eyes and a very blunt snout. They also “sing” haunting vocalizations, with their mouths closed, uniquely.
- Bearded seals, which stand out in that they possess characteristics of both main subgroups of the seal family. They get their name from their incredibly thick and curly whiskering.
- Caspian seals. These seals are found only in the salty Caspian Sea, the world’s largest lake. They’re so small that they are a common prey choice of the Pallas’ fish eagle.
Anyways, that about covers all of the oddballs in the true seal family. I hope you’ve all enjoyed reading, and have a nice day.