Ocean Watch

Monday, December 29, 1997

So, why the heck are they
called sperm whales?

THANKS to e-mail and starbulletin.com, I hear from a lot more readers than I used to. Here are a few recent questions and comments:

A reader named Dan writes: "Mahalo for the interesting column on the sperm whale (Dec. 15). You provided many interesting details on the creatures' physiology, diet, history and commercial uses.

"What's glaring in its omission, however, is why in God's name is this creature called a SPERM whale? Inquiring minds deserve to know."

Indeed they do.

Much of the bulk of a sperm whale's enormous head is taken up by a barrel-shaped organ called the case. Inside the case is a clear, liquid oil that when cooled, hardens to resemble white paraffin.

Because whalers thought this stuff looked like whale sperm, they called it spermaceti and named the animal a sperm whale.

Spermaceti was used as lubricant and lamp fuel until around the end of the 19th century when petroleum products replaced it.

Another reader, Charles, wrote of an experience he had at Ala Moana Beach Park: Last November, lifeguard Helene Phillips "scooped a strange object into a Styrofoam cup at the water's edge. She handed it to lifeguard Bill Goding, who called us over. The thing was one piece, not broken off something else, and had no obvious breaks or ruptures.

"It was maybe 15 inches long and an inch or so in diameter, translucent, jellyfishlike, but stronger and didn't break when held by one end.

"It had no internal organs, but was suspiciously organic-looking.... No, it wasn't a condom, though a condom closed at both ends and filled with clear Jell-O would be a fair description. What's your guess?"

A good find!

Although I didn't see the creature, and I don't know why it would be closed at both ends, the thing sounds much like a pyrosome.

Pyrosomes are gelatinous, free-swimming relatives of sea squirts. Brilliantly luminescent (pyrosome means "fire bodies"), these white creatures have an opening at one end like a condom.

Individual members of a pyrosome colony lie in the cylinder's jellylike walls with their mouths facing out. Tiny beating threads in the mouths move water and nutrients inside the tube. This not only provides food and oxygen for the individuals but also propels the colony through the water.

The length of these colonial animals ranges from an inch or so to over 30 feet long. A photo in one of my books shows a scuba diver examining one 3 feet in diameter, and he's almost completely inside the animal.

My own experience with a pyrosome was with a smaller one, about 2 feet long, in the Galapagos Islands. I was descending on a drift dive when a pyrosome floated into my face and flashed its brilliant white light. I was so startled, I didn't have the sense to grab it for a closer examination.

When a pyrosome encounters an object, a wave of light moves along its body, which frightens potential predators.

It has been suggested that the 1964 reports of a torpedo attack in the Gulf of Tonkin, which escalated American involvement in Vietnam, might have been pyrosomes, common in the area.

Now there's a sobering thought.

On a happier note, I'll end my column year with a comment from an Australian reader, Dieter: "A yabbie in Australia is a small crayfish, not the giant monster you wrote about (Aug. 11). Yabbies live in holes along the banks of any billabong.

"A much larger crustacean called the Murray crab can be found in the Murray River. Both Murray crabs and yabbies are good bush tucker-fair dinkum!"

Oh, I'll never learn Australian!

Thanks for writing, everyone. Your letters made it a great Oceanwatch year.