Central Coast Critters: Hydrodamalis cuestae

Hey there every peoples!

As you may have figured out by now, this blog is chiefly about paleontology on the Central Coast. And I thought that the best way to kick it off is with a creature that has it’s roots here. And as the title suggests, that creature is Hydrodamalis cuestae.

Hydrodamalis cuestae has been found in California, Baja California, and Japan. But it was first discovered here on the Central Coast. Back in the seventies, the holotype, which includes a skull and partial skeleton, was excavated at Avila Beach. It hails from the middle Pliocene Pismo Formation, around 3.5 mya. The excavation was carried out by Cuesta College (the school I currently attend) and at least some prep work was done at Cal Poly. Then somehow it wound up at Berkeley. Here’s a shot of a cast of the holotype skull, which sits in a cabinet in the Geology Lab:


Cast of the holotype skull of Hadrodamalis cuestae as seen in Mr. Grover's Geology Class

Hydrodamalis was a big animal. It is quite possibly the biggest sea cow ever. Stretching over 25 feet from nose to tail, it may have weighed as much as 11 tons. That’s the equivalent of 22 real cows! And one specimen from San Diego could have been over 30 feet long. Here’s a fleshed out/skeletal reconstruction at the San Diego Natural History Museum:


Fleshed out model of Hydrodamalis cuestae

Skeletal half of the above reconstruction

Hydrodamalis cuestae may have been big and a local celebrity, but it’s biggest claim to fame is that it was the progenitor of Steller’s sea cow, Hydrodamalis gigas. Steller’s sea cow went extinct in the 18th century not long after being discovered. It’s slow and gentle nature made it an ideal target for sailors.


The fate of Steller's sea cow

It’s hard to say how long they would have lasted had they not been hunted to extinction. Apparently the sea cows discovered by Steller were a relict population. They lived around a small island group in the Bering Sea, found barely enough food to stay alive, and were often injured and suffocated by ice flows. You’d think an animal who lived in the North Pacific would have adapted to it.

Who knows why H. cuestae moved north the way it did. Could it have been a loss of habitat? During the Pliocene California’s shoreline was a mosaic of bays, inlets, and estuaries. A quick trip up the Big Sur coast shows that this is no longer the case. California’s shorline today harbors few bays (which is why it wasn’t as attractive to settlers, but Spain claimed it nonetheless) and is so rocky the rocks have their own national monument. Regardless of how it went extinct, Hydrodamalis is a neat creature, a blown up version of a familiar animal we see today. For me, the best part is he “got his start” right here.


Till next time!

2 thoughts on “Central Coast Critters: Hydrodamalis cuestae

  1. Great post, Doug, great blog!!
    I’m particularly fond to see Hydrodamalis cuestae as the start of it all. Daryl Domning was my advisor and I still try to focus my energies on Sirenia and Desmostylia. It is a joy to see someone else appreciate these marvelous beasts.
    I’m looking forward to seeing more posts like this.
    Best wishes,

    • Thanks Brian! Pinnipeds, Desmostylians, and Sirenians are where it’s at. I have loads of ideas, but am being rather conservative with posting them. I’m waiting to see if i get a few more readers/watchers (cause when you have more, you have to give up the goods more often, it seems).

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