CASPIAN SEALS!!!

Tavishi

I'm a big fan of small creatures, especially insects, and even tinier, my dog.

Anyways, one of the smallest pinniped species, and the smallest phocid (eared seal) species is the Caspian seal, Pusa caspica.

There are three seals in the genus Pusa- the Baikal seal (P. sibirica), Caspian seal (P. caspica), and Ringed seal (P. hispida). Of these three species, the Baikal seal and ringed seal are the most popular in general, generally for their usage in memes.

pitiful little Niko

What's important to note about these three species is that they are all related (generally this is in fact how phylogenetics works.) The Caspian seal is found in the landlocked brackish Caspian sea, and the Baikal seal in the weird freshwater Lake Baikal, but the Ringed seal has a much larger ocean range.

All three species have similar size, body shape, and eye size, which indicates relatedness. However, similar morphology can evolve from different origins: see convergent evolution. Anyways, there's other evidences like genetics and range indicating the species to be pinniped cousins, but it's hypothesized that the Caspian and Baikal seal both evolved from ringed seal populations having moved inward into Eurasia.

caspian sillie

The caspian seal is pretty cool and cute, and of all members of Pusa, is the most endangered.

Caspian seal breeding season begins in the early months of the year, spanning from

early January to late February, shortly after the birth of new pups. All pups are born on land, either on ice fields, or on rare occasions, on beaches. Ice fields are primarily found in the north region of the Caspian, and are, in fact, cold.

As most phocid pups, caspian seal pups are born with a white fluffy lanugo coat, keeping them warm despite freezing temperatures. This is, as expected, the case with most cold water phocids. Notable exception are monk seals, which are warm water phocids, and don't really need lanugo- see: w a r m t h .

Caspian seal pups are weaned at about the same time they are shedding their lanugo. At this point, they are able to enter the water for themselves as they are fat enough to not turn into pinnipopsicles.

After caspian seal pups are weaned, their mothers get back in the game and begin mating again.

Mating occurs underwater. I will leave further information on the matter as an exercise to the reader.

After mating season ends, caspian seals undergo an annual catastrophic coat molt.

Anyways, as a pathology nerd, I obviously cannot let y'all go without hearing about the diseases these little creatures contract.

Caspian seals get canine distemper virus, which is a morbilivirus not limited only to canines. (Pinnipeds are canids, but not canines.) Anyways, not a great virus. Canine distemper killed off a bunch of caspian seals near 2000, which was pretty unfortunate. Damn I am sleepy.

Symptoms in pinnipeds generally include pneumonia and encephalitis, with respiratory issues being the first signs of distemper. These symptoms similarly overlap with those in dogs. The initial fever in dogs builds up about 3 days after infection. Neurological symptoms are the biggest tell in dogs.

Histological lesions present are characteristic of pneumonia. Distemper, however, is diagnosed through its intracytoplasmic inclusion bodies (wow the beauty of pathology!!!!). The arrows in the image above point to eosinophilic (pink) inclusion bodies in the cytoplasm, which are just clusters of virions.

Caspian seals are very cool, and I am very sleepy, so this is not a coherent post.