All whales and dolphins seem to have blowholes in the center of their heads, but the sperm whale’s is situated forward and to the left. Why is this? There has to be a reason. This has been driving me crazy since I was in elementary school.
Also, to my knowledge it’s the only mammal that doesn’t have a symmetrical (bilaterally symmetrical?) anatomy because of that. That’s just off the top of my head though, and I’m probably wrong.
I’ve searched for the answer high and low, and the straight dope is my last hope.
Wild Ass Guess Here.
I have seen sperm whales up close before. When they surface for air they are up for quite some time. About 15 min. or so. That is because they are catching there breath from being under for so long. They cant just come up for a brief breath. That is why it is easy to pull a large boat right op to one. They have to get that breath. Other whales and such dont stay down for so long so thay can keep coming up. Catch a small breath if need be.
Now for the reason for the off center blowhole. Because they are on the surface for so long and dont have much of a choice, in rough seas they possably could drown at the surface. Trying to catch your wind after being down fro 30 min. and waves crashing ontop of you could spell trouble. If their blowhole is off center they may be able to position themselves in such a way as to get more air.
I cant remember what direction they are in relation to the larger waves but I seem to remember it being a constant.
I am no Art Vandelay but that is the best I could come up with.
I’m not a doctor or an expert in anatomy but we don’t have complete bilateral symmetry either. We only have one heart and it isn’t symmetrical, one liver, one gall bladder and one spleen all on just one side, one appendix, our lungs aren’t identical and there are probably others that I don’t know anything about.
It is true that we have external symmetry and maybe that’s what you were referring to.
Don’t Sperm Whales have a sort of ‘oil tank’ in their head ? (Whale oil comes primarily form Sperm Whales) this would take up a certain amount of space and maybe throw the blow-hole off to one side.
My personal WAG is that based on the need to stay surfaced for a longer stretch than most whales having the blowhole off center allows them to keep one eye down in the water to see predators or prey.
So, while the best whale oil came from sperm whales, it wasn’t the majority. Right Whales were considered the best choice for whaling since they were slow swimmers, rich in blubber to make oil, and floated when killed.
Like a lot about whales, this is not a well-understood adaptation. You mention one of the ideas out there about keeping the blowhole in the lee of wave spray to prevent inhalation of water, but there’s also thoughts about its position in relation to the production and transmission of sound (it’s adjacent to, but anterior to the spermaceti organ, and echolocation is very important to sperm whales, but most dolphins similarly dependent on echolocation have their blowholes posterior to the melon)
I checked a couple Marine Mammal texts: Leatherwood et al.’s Whales, Dolphins, and Porpoises of the Eastern North Pacific and Adjacent Arctic Waters and Folken’s Guide to Marine Mammals, and while both mention the unusual position of the sperm whale’s blowhole, neither comment on why.
Actually, in a lot of organisms it’s very difficult to get an answer to the question “Why is {insert feature} this way?” It’s a very adaptationist perspective that’s a little frowned because of modern evolutionary biology’s attempt to avoid just-so stories. So I’m guessing you won’t find a lot of solid evidence.
What I can say, though, is that perhaps this citation may have information on the acoustic aspects: K. S. Norris and G. W. Harvey, in NASA Spec. Publ. 262, edited by S. R. Galler et al. (1972), pp. 397–417
I haven’t read it, though, so I can’t say.
Telemark, good point on the right whale’s name. I’ve heard that too.
On the plus side, sperm whales seem to be the target of lots of research these days, so maybe more information will come to light soon.
You had to know that eventually someone would come along who would either know the answer, or know the latest scientific hypotheses concerning the position of the sperm whale’s blowhole. Gotta love SDMB.
I have been waiting for the OP to get a factual answer so I could quote Chris and Peter Griffin:
Chris> Dad, what’s a blow hole for?
Peter> I can tell you what it’s not for, and once I do you will understand why we can never go back to Sea World.
