A bit of googling has offered only one discussion that I can find, from Herman Melville’s Moby Dick:
Are the scratches from fighting with other whales, as Melville suggested? If these scratches do only appear on males it could be evidence of tournaments for mating rights, but looking at the scratches in the photo linked to and the jaw and teeth of the whale it doesn’t look as if it would be easily able to produce a scratching pattern like that, especially along the side of the whale’s body. Sperm whales use echolocation, biological sonar, to form a picture of their environment so it seems unlikely that the scratches could come from scraping against things like rocks or icebergs. Or could they be scratches from the hooks on the tentacles of sperm whales’ frequent prey - giant and colossal squid? What’s the cause?
The last photo shows the scratches the best. I agree it does not seem likely that those are from other sperm whale teeth - they seem too far apart to agree with the dental pattern of another sperm whale. I am no expert, but it seems like those are from the hooked tentacles of the colossal squid, raked across the flesh, as The Great Sun Jester suggests. They are all near the mouth as well, suggesting a battle that ended in a meal for the whale.
Yes, according to wikipedia, giant squid “only” have “suckers lined with small teeth”, while the colossal squid’s limbs are “also” equipped with “sharp hooks: some swivelling, others three-pointed”. :eek:
Interesting article - its authors suggest that the sperm whale’s distinctive bulbous forehead has evolved for male-to-male “battering-ram” fights, and includes a couple of good historical accounts of sperm whales striking and sinking ships. It also has a photo of scars that look not dissimilar to those seen on the whale in the photo I initially remarked on. Here are the parts of the article that mention the scars (and, please, no giggling at the back on learning that the technical term for the thing encased within the sperm whale’s enlarged head - the “spermaceti organ” - is “the junk”):
The whales that beached in the U.K., now numbering five, were indeed males - described by one scientist as a “bachelor pod” - so that ties in, at least.
The second link in my OP is a documentary-style video sequence from Youtube, but created using computer-generated imagery (since actual footage is not yet available). It shows a sperm whale attacking a colossal squid and the squid’s hooked tentacles ripping the whale’s flesh drawing blood, which I imagine could leave scars similar to those seen in the photo. The video is apparently from a BBC programme (from the same people who did similar CGI recreations like Walking With Dinosaurs).
Wikipedia also says that the “white scars [on sperm whales] are believed to be caused by the large squid” (without citation) and a couple of other online sources make similar statements but without additional elaboration.
I’ve seen a couple of slightly different angles of this particular beached whale in the article and the scratches visible in the photo seem to account for most of the scratches on its body - they appear on the front and side of the whale but little on its top and bottom (dorsal and ventral sides). There aren’t many scratches around the mouth, though, as one might expect to see if something was trying to eat a colossal squid.
In any case, to complicate matters, here’s a photo from wikipedia of another sperm whale with scratches located almost inversely - around the mouth but not on its sides (perhaps as a result of the “jaw-to-jaw wrestling matches” described in the article quoted above).
So, the online source which looks to have presented the most supporting detail suggests these scratches are “probably” the result of tooth-raking from other sperm whales rather than fights with colossal squid, but I don’t feel fully convinced yet either way.
Having unexpectedly looked at lots of photos of sperm whales today, I do have to say that the scarring on the particular beached specimen in the article looks to be quite exceptional (and here’s a relatively scar-free fellow member of his pod, for comparison). Was this whale a winning lothario who vanquished all other love rivals in combat and had the scars to prove it or a wimp that came out worst in every male-to-male “battering-ram” contest he entered? Alternatively, was he the veteran hunter of a thousand colossal squid or the guy that other whales laughed at because he was always the one who’d end the hunt with a squid stuck to his face?
Yes, that looks to be the leading consensus for its primary function. Other theories for it include buoyancy assistance and as an ultrasonic hunting tool to stun its prey (although that looks to have been disproved). The hypothesis that the oil-filled sacs of the spermaceti evolved as a shock absorber for “battering ram” contests doesn’t appear to be the current mainstream scientific thinking.
They’re quite consistent with the notion of a large squid clawing and scrabbling to get away from the mouth, which is what I would do if a sperm whale was trying to eat me!
If you look at the scratches on the front end of the whale’s head, there is a pattern where the same scratches are repeated three or more times at regular interval - consistent with having been created by three or more sharp objects equally spaced along a line - this could mean teeth in a jaw, or hooks on a tentacle.
More telling, I think, are the clustered wavy lines of scratches a little further back, and the radial pattern of scratches further back still - all pretty consistent with damage done by something flexible, with spikes on it at regular interval = squid tentacle.
The only thing that makes me doubt this a little is the possibility that the scars were formed by an attack from something with jaws, when the animal was newborn, but even then, there aren’t many things that can get their mouth around a newborn sperm whale’s head.
It’s possible. One would presume that the sperm whale would grab the squid in its jaws from the head end to get a better grip and minimise the opportunity for the squid to manoeuvre its beak into biting range. This would potentially put its tentacles in the approximate area of the whale’s scarring.
Since we have visual evidence of scarring on whales from giant squid’s tentacle suckers, it seems reasonable to assume that the tentacle hooks of the even bigger colossal squid would also leave visible scar patterns.
We know from the contents of sperm whales’ stomachs that they eat giant and colossal squid. These rare photos show a female sperm whale with the remains of a 9-meter giant squid in its jaws and there are plenty of popular imaginings of squid vs sperm whale battles.
On the other hand, this photo shows that the sperm whale is able to open its jaw to a wider extent than one might expect, therefore giving creedence to the notion that a sperm whale would be physically able to rake its teeth against the side of another whale.