#the cetacea

[intriga-hounds]

to celebrate me finishing my draft, one of my writing group friends made me my very first fan art out of modeling chocolate 😭 i was so touched. i couldn’t stop looking at it. it’s sitting in my fridge bc i can’t bear to eat it.

[inatungulates]

Eden's whale "Balaenoptera" edeni

With menhaden Brevoortia sp.

Observed by haitongyu, CC BY-NC

[feather-bone]

Bowhead whale! The longest-lived mammal, reaching ages of over 200.

[ID: an illustration of a dark grey whale with a white chin swimming in profile to the right. The background is a wavy sea on the bottom and a sky of planets in orbit on top. End.]

[snototter]

A pod of Hector's dolphins (Cephalorhynchus hectori) leap from the water in Aotearoa

by Anjanette Baker

[have-you-seen-this-animal]

Southern right whale dolphins

Oh a very cool one, hadn't seen them before! Thank you!

Photos from Gerard Bodineau & Toby Dickson, respectively.

[arminreindl]

An attempted at a size comparison of Romaleodelphis, the recently described "dolphin" from the Miocene of Austria. I couldn't find any good material of the closely related Chilcacetus, so instead based the proportions more on eurhinodelphinids, so take the size with a grain of salt.

Romaleodelphis is a recently described species from the Early Miocene Konservatlagerstätte at Pucking, Upper Austria, which preserves fauna dating to the early Miocene when much of eastern Austria was underwater. A somewhat generalized depiction of this time was actually drawn very recently by @knuppitalism-with-ue (I still got a half-written reblog of his piece sitting in my drafts). Of these animals, the giant sunfish Austromola and the loon Petralca are both from the same locality as Romaleodelphis, which sadly didn't make it in on account of having been named just a week too late.

[harpagornis]

Are we reconstructing early whales right?

Sea lion skull. Note the retracted nostrils, when the living tissues make the nose not that different from other carnivorans like dogs and bears.

Primitive whales get the short end of the stick when it comes to depictions in media. They're drawn as thin, almost reptilian monstrosities. Most notably, their nostrils are almost always retracted, giving them a very odd, saurian profile.

Rodhocetus by Nobu Tamura, one of the better depictions, though still having retracted nostrils.

This makes sense. After all, the skull bones show a retraction of the nostrils in the snout. But this also occurs in other marine mammals; in fact, both pinnipeds and sirenians also have retracted cranial nostrils, but the soft tissue nostrils are still elongated and forward-pointing.

A manatee. Their nostrils are as cranially retracted as those of whales, but the soft tissue nostrils form a short forward facing proboscis.

I believe this should be taken into account when depicting extinct whales. Expecially since some do seem to have forward facing bone nostrils.

Coronodon by  Boessenecker​ et al 2023. Note the strut of nasal bone pointing forwards; could it imply longer soft tissue nostrils?

Food for thought.

[wind-tied]

some cetacean ocs :)

[a-minke-whales-tale]

A helpful reference

[uncharismatic-fauna]

The Beautiful Boto

Also known as the Amazon river dophin or the pink river dolphin, the boto (Inia geoffrensis) is a species of toothed whale native to the Amazon and Orinoco river basins in South America. Because they reside mainly in rivers, lakes and mangroves, the boto occupies a large range; nearly 7 million square kilometers (435 thousand square miles). Despite being related to whales and dolphins, I. geoffrensis cannot tolerate saltwater and is only found in freshwater.

The Amazon river dolphin is the largest of the four river dolphin species, weighing in at 98-185 kg (215-407 lbs) and measuring 1 to 2.5 m (4-8 ft) in length. Males are larger than females, and are a bright pink to the females’ dull grey. A significant part of the length comes from the dolphin’s distinctive long snout, which is used to hunt for crustaceans and small fish. The boto’s body is designed to be highly flexible, which comes in handy when navigating through flooded forests. One adaptation in particular that makes I. geoffrensis stand out is the unfused neck vertebrae, which allows them to bend at up to a 90-degree angle. Botos also use echolocation to navigate murky river waters. which is enhanced by the large melon on their foreheads.

Breeding for the pink river dophin occurs between May and June, during the rainy season when flooding is at its peak. Males will fight for access to females, and will also perform courtship displays that involve carrying a number of objects-- like branches, fish, or even live turtles-- and slapping them into the water. Successful pregnancies last 11 months, and after giving birth mothers raise their young in the slow-moving waters of flooded forests. Weaning takes about a year, although mother-child pairs will often stay together for much longer. The average lifespan of the boto can be anywhere from 10 to 26 years, as they have no natural predators.

Outside the mating season, I. geoffrensis is a solitary creature. It’s rare to see groups of more than three at a time, and do not heavily defend set territories. However, they are very curious and have been known to readily approach canoes or play with debris in the water. Individuals have also been seen hunting fish in loose cooperation with other species like giant river otters (Pteronura brasiliensis). The bota is crepuscular, active mainly at dawn or dusk, and generally stay close to the surface of the water. Deep dives are rare, as they can only hold their breath for 110 seconds.

Conservation status: Hunting pressure and pollution, as well as dam building and deforestation, are major threats to the amazon river dolphin, which has been classified as Endangered by the IUCN. Conservation efforts are being made, but the species is difficult to keep or breed in captivity so most work is being done in the wild.

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Photos

Sylvain Cordier

Kevin Schafer

[de-sir-ee]

“Sea Canary”

[rosycheekies]

Laundry Cat by cetacea kw

[inatungulates]

Grey whale Eschrichtius robustus

Observed by susannespider, CC BY-NC-ND

[feather-bone]

Amazon river dolphin! The pink one!

[ID: a digital illustration of a pink and grey dappled dolphin leaping, facing to the right on a dark teal background. It is smiling and is surrounded by decorative, stylized waves and splashes. End.]

[snototter]

The eye (and ear opening) of a Beluga whale (Delphinapterus leucas)

by Eric Heupel

[have-you-seen-this-animal]