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Saturday, February 1, 2014

Whale on the beach

On Friday we heard that a young Gray Whale (Eschrichtius robustus) had washed up dead just north of Salmon Creek Beach.  I decided to drive up during my lunch break to take a quick look.  I learned that this whale had been around for a while (further north), so its condition had been deteriorating for at least 10 or more days.  But it still seemed like a record worth documenting.  (If you'd rather not see pictures of a dead whale, look no further.)

This is a dorsal view (the upper surface) of the whale.  It was ~18 feet long.

And a ventral view (lower surface):

I learned that the average length of Gray Whale calves is ~4.6-5 meters (15-16.5 feet) and that they weigh ~1/2 ton.  [Compare that with adults which reach 12-15 meters (39-49 feet) and 15-35 tons.]

The next picture shows a head-on view where you can see the arched mouth (upper jaw on left, lower jaw on right):

Although most Gray Whale calves are born in Baja, since the 1990s around 20% of the females have given birth during their migration south (before arriving in Baja).  Many of these "northern births" have occurred in the Southern California Bight, but newborn calves have also been documented in northern California, Washington, and British Columbia.

Two more pictures: the first a close-up of the head/mouth and the second with the flukes and knobby tailstock.

Gray Whales become sexually mature in 5-12 years.  A female gives birth to a single calf every 2-3 years.  Calving generally occurs between late December and early March, with a peak between mid-January and mid-February.  Calves are weaned after 7-8 months (after drinking ~50 gallons of milk per day!), but spend another month or two with their mother.

I heard that scientists will be looking for a cause of death in this individual.  If I learn anything about it, I'll post additional information here.  (Feel free to write in if you've heard something more.)

P.S.  Facts in this post came from the Field Guide to Marine Mammals of the Pacific Coast (Allen, Mortenson, and Webb, 2011) and Whales, Dolphins, and Other Marine Mammals of the World (Shirihai and Jarrett, 2006).

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