I know sperm whales are weird, but...

There's no denying that Physeter macrocephalus - the Sperm whale or Great sperm whale - is a very special, very weird mammal, and (as yet) I haven't done it justice at Tet Zoo. That will be rectified in time, honest (I've been keen for years to write about the suction-feeding, and about the battering ram hypothesis). The excellent Zoological Museum at Copenhagen (Denmark) has tons of amazing specimens on display, and among them is this excellent mount of a Sperm whale and an assortment of other large mammals (photos courtesy of Markus Bühler).


But... something's not right...

Yes, this particular Sperm whale is either 'augmented' (incorrectly), or it represents one of the most unusual specimens ever obtained by science (and that's against some pretty tough competition). Check out the close-up of its jaws...


Most of you will know what I'm talking about: feel free to show how clever you are by discussing it all in the comments (and, as usual, it would be nice to get to the bottom of whatever happened here).

I might not have covered Physeter on Tet Zoo, but at least I have written about other physeteroids quite extensively. Please see...

And - teaser - Mehmet Köseman and I have collaborated on something to do with physeteroids. I haven't yet found the time to write it up. It involves the animal formerly known as Leviathan and just given the new name Livyatan.

And for more on odontocetes, see...


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It's got upper jaw teeth?

Teeth in the upper jaw ;)

But on the other hand, a lot of fossil physeteroids had teeth where this specimen shouldn't. To make it even more interesting, the recent fossil-derived phylogenies suggest that even though both living physeteroid genera lack upper teeth, their respective stem lineages lost the upper teeth independently.

At this point its probably been stated multiple times that the weird trait of this sperm whale skeleton is the teeth in its upper jaw. It almost looks as though the mounting team goofed rather than an actual atavistic trait based on the pictures shown here. The teeth don't really fit into their "sockets", in fact they almost resemble what happens when a bad sculptor tries to make teeth out of cheap, air-drying clay (although that's definitely not the case). Seeing that sperm whales have sockets on the upper jaw, not for their upper teeth but for the points of the lower teeth to rest in, the people reconstructing this skeleton probably got mixed up thought the upper sockets housed teeth as well.

Though it would be neat if there is any evidence to the contrary, and that this is a real atavistic specimen? Any information on such?

By Anonymous (not verified) on 30 Aug 2010 #permalink

Perhaps it came toothless (rotted out or removed) and someone told a well-meaning reconstruction person "Here's a bag of spare teeth, put them in the sockets."


this particular Sperm whale is either 'augmented' (incorrectly), or it represents one of the most unusual specimens ever obtained by science

Actually, the correct answer might be 'neither of the above'. Apparently, erupted upper teeth are not particularly uncommon in Physeter macrocephalus, although the upper teeth - when present - are usually not superficially visible when the whale is alive (Gibbs & Kirk, 2001).


Gibbs, N.J. & Kirk, E.J. 2001. Erupted upper teeth in a male sperm whale, Physeter macrocephalus. New Zealand Journal of Marine and Freshwater Research 35, 325-327.

I'm not buying the "fake teeth" hypothesis - not every socket has visible teeth, and the many of the teeth have an abnormal structure that one would expect from a development like this. IIRC, upper jaw teeth are not that unusual in Sperm Whales, but it is highly unusual for them to be this readily apparent out of the socket.

I know I'm not the first to say this, but it is the FIRST time ever on one of these challenges or yours I knew the answer on my own right away!

Why does it have upper teeth?!? All other Sperm Whales don't!

Man, Dartian beat me to it in pointing out that a fair portion of sperm whales actually have teeth in their upper jaw! BTW, the paper Dartian referred to is freely available online.

One of the more intriguing comments the paper relates is this: "Teeth also occur in the upper jaw in up to 50% of sperm whales (Matthews 1938). When they do, they are larger and more numerous in males than in females (Bullen 1899; Matthews 1938; Omura 1950; Clarke et al. 1968)[...]In most individuals, the upper teeth are not superficially obvious (i.e., the upper jaw appears toothless), but dissections have revealed 1-15 small, curved teeth within the gum on each side (Boschma 1938; Clarke 1956; Clarke et al.1968; Rice 1989). The upper teeth have been found near the edges of the pits in the upper jaw, in the bottoms or sides of the pits, medial to the pits, in the lips, or in the intervals between successive pits, with two teeth within the one interval in some instances (Bennett 1836; Beale 1839; Bullen 1899; Boschma 1938; Matthews 1938; Clarke 1956; Clarke et al. 1968; Berzin 1972)." So, just because the teeth appear not to be in the sockets in the specimen in the photo provided does not necessarily mean the teeth are "faked".

By Zach Armstrong (not verified) on 30 Aug 2010 #permalink

As Dartian and Zach already mentioned, upper teeth are known from Physeter; the Smithsonian has at least one in storage. When present they are always small, and they aren't typically rooted in alveoli. However, I have seen several specimens that also appear to have a rudimentary alveolar groove in the maxillae; at least one of these also had upper teeth, but they weren't actually in the groove.

Dumbpedia says: teeth are sometimes present in upper jaw, but they rarely erupt from gums.

But these look a bit strange, thickest in the middle, maybe due to their atavistic nature.

I have also a book about sperm whales which shows very well (and at large size) teeth from the upper jaw compared to those of the lover jaw. To get the upper teeth you have (in general) to rott the skull or gouge them out of the bone. Those teeth are as already said by former commentors much smaller than the lower teeth, sometimes strongly curved, and often somewhat misshaped.

Something what I also wanted to emphasise is the huge size of this particular sperm whale skeleton (it belonged obviously to a bull). I have already seen several several other jaws or skulls of sperm whales, but this was by far the largest. If you look how minute the two bears and even the hippopotamus skeleton look compared to it, you get a good idea how huge it was.

Just a reminder that the presence of upper jaw teeth in Physeter was mentioned back in the Killer sperm whales article (August 2008)...

The extant sperm whale Physeter lacks functional teeth in the upper jaw and in fact even possesses special sockets in the maxillae that house the lower jaw teeth when the mouth is closed (it may actually have as many as eight teeth in each maxilla, but when it does they are unerupted and remain buried in their alveoli).

Needless to say, I was unaware of Gibbs & Kirk (2001) when I wrote this. If these teeth are genuine, this specimen will remain an exceptional one in view of its high number of upper jaw teeth: there seem to be 11, which is close to the (rare) record number of 15. I therefore will be standing by my claim that it, potentially, "represents one of the most unusual specimens ever obtained by science"!

Just checking through my photos; I have an image of a USNM specimen has at least 6 left maxillary teeth. My image is a closeup of the teeth, so I don't if it had more than 6 (I wasn't there to work on sperm whales that day). They are about 1.5-2 cm in length, peg-like with a pinched apex, and lack enamel. There do not appear to be any alveoli associated with them. They also show no obvious signs of wear, so they were presumably completely embedded in the gums.

Given the above, it could be an extreme of the normal range, in which the teeth are actually erupted. They look much smaller and thinner than the botom teeth, and seem to have a regularity in their size (the posterior ones being the smaller). Following Sordes' remark about the large size of the whale, maybe they are equivalent to our 'wisdom' tooth and they erupt in late life and they are only apparent in very old specimens.

If these teeth are genuine

'If'? You've become such a sceptic, Darren. ;)

Sordes/Markus: You were at the museum; was there any information about that particular sperm whale specimen? When and where it was collected, comments about its dentition, etc.?

Something what I already asked me some time ago is if the socket in the upper jaw in which the teeth of the lower jaw fit, are physiological or to some degree pathological. With "pathological" I mean that it could (this is of course only a vague idea) be that this sockets could possibly form mainly as a result of the permanent penetration by the lower jaw´s teeth into the gum. If you exert pressure on tissue, especially bone, over a long time, the tissue will atrophy. This is as said only an idea about the possible origin of the sockets. Of course it could also be that they just form naturally. It would be interesting to know if such sockets are also present in toothless sperm whales, or at parts of the jaw where the antagonistic lower jaw part has missing teeth.

@Dartian: I saidly have no idea. There was so incredibly much stuff in the room (as well as in the whole museum), that I didn´t read everthing. I just took again a closer look at my original photos. It seems that some of the teeth are not even in alveoles, but are connected with the bone with partly still visible screws or wires. The most anterior tooth on the right side (not visible at the small photo here) looks if it had only erupted for some milimetres, and is still mainly embedded into the bone.

Sordes: Thanks for the reply. But, surely there must be at least some other Tet Zoo readers who've been to that museum and who might know something about that particular specimen? Hvor mange danske folk læser denne blog?

Like post 9 above, I'm also quite excited, as a non-biologist, to be able to correctly answer the question posed. But only because two weeks agao I saw a sperm whale jaw at the Oxford Museum of Natural History and thought "Hang on, it's got no upper teeth."

Wouldn't it be fab if they could find a fresh dead one for Inside Nature's Giants sometime?

By MJ Simpson (not verified) on 30 Aug 2010 #permalink

Sordes: Actually, I prefer not to reveal that in a public forum. But check your e-mail.

Loss of the upper teeth and the presence of sockets for the lower teeth to fit into suggests adaptation for specialised feeding. Therefore, if these upper teeth in this specimen are genuine, how might they have influenced feeding efficiency? In Peter Best's 'Whales and Dolphins of the Southern African subregion', he says 'although the majority of adult sperm whales have no erupted teeth in the upper jaw a few possess 9-10 pairs...smaller and strongly curved....the incidence of maxillary teeth increases with body length [comment 5 by Sordes] in both sexes with a secondary increase at a BL of 14 - 14.9 in males (coinciding with social maturity [suggesting a function?]). Best also says that up to 1% of whales have bent, curved up or 'scrolled' or abbreviated jaws such that dentition becomes functionless at grasping food! But they do not 'seem to suffer any nutritional deficiences'.

THOSE are upper jaw teeth.

Oh! Neat! Vestigial upper teeth! Incidentally a week ago I was talking with a paleocetologist at the NMNH about Livyatan, "Ontocetus" oxymycterus and other sperm whales and he mentioned the presence of vestigial teeth in some Physeter macrocephalus. BTW, Dartian, thanks for providing the reference!

Strictly teuthophagous marine predators don't really require teeth for prey capture; most Ziphiids (beaked whales) have lost almost their entire dentition, save for a pair of tusks used for intraspecific combat (they are not used for prey capture). The loss of teeth in most beaked whales is possibly an adaptation to increase the probability of maintaining a seal during oral suction (although I've also heard that tooth reduction is possibly also related to reducing hard points that cephalopods can latch on to). Sperm whales, on the other hand, are able to exert oral suction in their throat rather than the oral cavity proper, explaining the rather high incidence of oral pathology in sperm whales (i.e. oral pathologies don't negatively affect fitness). The phylogenies presented by Lambert (2008) and Lambert et al (2010) show that the upper dentition is independently lost several times within the physeteroidea.

Yes, which suggests that teeth may have another function related to sociality? Some other toothed whales have very strange teeth, exagerrated by sexual dimorphism

Being a frequent visitor to this site and working at the exhibition department at The Natural History Museum of Denmark I think I will comment on the whale in our Evolution Exhibit.

Our specimen is from Iceland, caught June 1903 (under captain M.C. Bull). It entered our collection the following year. The mounted skeleton (without the skull) measures approx. 14.7 m, the head 5.5 m, and the lower jaw 4.9 m. The skull had to be cut up in four parts to enter the door at the old museum in the center of Copenhagen. According to Wikipedia, Nantucket Whaling Museum claims that a 5.5 m long lower jaw belongs to a 24 m whale. I suspect that a lot of mounts underplay the sizes of big whales, as they rarely take the thickness of the spinal discs into consideration (the whales on display in Bergen, Norway, being an exception). There are several sperm whales in our collection, one of them with a skull only slightly smaller than the mounted one.

According to L. Harrison Matthews ("The Sperm Whale, Physter catodon", Discovery Reports, 1938), about half the examined whales from South Africa and South Georgia had one or more teeth in the upper jaw, "... either completely imbedded, or with the tips only cutting the gum ...". The largest number found was eleven, all in one side of the jaw. Incidentally, one of our staff, a conservator highly experienced in big whales (we had a lot of beached sperm whales in Denmark in the 1990's), also told me that every old whaler knew teeth were frequently found in the upper jaws of large sperm whales. They probably go unnoticed in most rotting whale carcasses. Our mount has 22 teeth, eleven in each side, and I will have to ask a member form the retired staff to find out if this really was the case, but according to the records a number of small teeth were sent with the whale (we also got some ambergris and spermaceti). And to curb any criminal enthusiasm, all the teeth are casts, the real deal is much too valuable - and the mount within reach of the public. I'll be back!

By the way: Matthews' book is a mine of information, and I now know that large males had about 20 liters of testes, and the corpus luteum in pregnant females are up to 10 cm in diameter.

Jørn Madsen

Jørn: Thanks for that information. Hope you can track down the rest of that whale's story too.

all the teeth are casts, the real deal is much too valuable - and the mount within reach of the public

Ah, yes, that's right; many museums don't keep their genuine sperm whale teeth on display because of the risk of theft (they're ivory, after all).

Stop the press.

I have given you all a wrong measure for the skeleton (one of our students measured it a few minutes ago): The postcranial skeleton is a little less than 10 m!

This puts the claim of the Nantucket Museum into perspective.


Jørn Madsen


That's exactly the suggestion - that ziphiid tusks are retained for interspecific combat, and that teeth in Physeter are used for social interactions (i.e. jousting between males).

I think it's more likely that rather than having any specific evolutionary purpose, the various changes in the teeth of cetaceans have resulted as a secondary characteristic from mutations of genes fulfilling a different evolutionary purpose. Similar to the way changes in hair and eye color in Canidae result from mutations to the adrenal gland.

By Diogenesis (not verified) on 03 Sep 2010 #permalink

Diogenesis: That's exactly not what the body of literature on marine mammal dental evolution indicates. Unlike eye color, dental morphology has a very specific adaptive purpose - most often related to food procurement and food processing, and also intraspecific combat (i.e. hippos) and display (cf. warlruses).

For example, Uhen (2007) has argued that new feeding resources are the most important driver of terrestrial tetrapods back to the water, based on the fact that dental features and the feeding ecology of each secondarily aquatic tetrapod group are the first features to radically change in the early evolution of said groups. There is also a suggestion (by Colin MacLeod (sp? McLeod?) that the functionally similar but slightly differently shaped tusks in Ziphiids also fill a display related, species-recognition role (similar to what's been proposed for ceratopsid dinosaurs), a suggestion I find very intriguing.

Anyway, the assertion that cetacean tooth morphology is not related to feeding ecology is simply unrealistic (and very easily tested); I'd check out papers by Alex Werth, e.g.:

A.J. Werth, Mandibular and dental variation and the evolution of suction feeding in Odontoceti, J. Mammal. 87 (2006), pp. 579â588

2007: Uhen Mark D Evolution of marine mammals: back to the sea after 300 million years. Anatomical record (Hoboken, N.J. : 2007) 2007;290(6):514-22


Colin MacLeod (sp? McLeod?)

MacLeod is correct.

One would think that there must be a scrimshawed upper sperm whale tooth somewhere. It wouldn't present the surface area to work with that a lower tooth would, but the novelty and challenge of a smaller surface might have appealed to a whaler/artist. It'd be the sort of thing that might have made a nice carved or scrimshawed tool or knife handle perhaps.

I helped butcher a sperm whale near Homer Alaska. We collected 18 vestigual teeth from the upper gums. None fit into sockets, and all were pretty much buried in the gums. They appear to be the same material as the teeth in the lower jaw. We sliced one open and was able to age it the same as the teeth in the lower jaw- got the same age even.
I looked at a second sperm whale and collected a vestigual tooth from it that was about to fall out. It appears as the whale rots -the gum tissue got soft and shrank and those teeth fall out easily .The lower ones were gone already. The teeth in this whale skeleton do not look much different in size or shape from the ones we collected from two other sperm whales. Lee Post