Last year the blogosphere and global media went nuts over the ‘Montauk monster’. A small mammal corpse that washed up on the beach at Long Island, New York, it was not an alien, government experiment, or sea-monster, as widely claimed by idiots worldwide, but – without doubt – a dead, rotten raccoon. This month a vaguely similar sort of thing is happening, though this time there is less hype. And, for me, the corpse is closer to home, having been discovered on Croyde Beach in Devon, southern England [its skull is shown at left]. The Croyde carcass made several national newspapers, including The Daily Mail and that most reliable of sources, The Sun.
Here we come to an example of journalism at its best (read: worst). Croyde Beach is in north Devon and not too far from Exmoor. The corpse belonged to an animal that was dark in colour and had big pointed teeth (see photos). Add two and two, make five, and you have journalists claiming that the carcass might be ‘the beast of Exmoor’. Yes, the ‘beast of Exmoor’, a label more usually associated with the big, often black cats that people see in and around the Exmoor region. Big, non-native felids definitely do prowl around the English countryside*, but what the hell does this carcass have to do with them? Nothing: it is clearly not a cat carcass. To be fair, however, the claim that it might be a big cat carcass had been made by people that had been on the scene, mostly notably a police sergeant who noted that the carcass ‘certainly looks quite beast-like’. Yeah, good work there sparky.
* Those lamenting the conspicuous absence of British big cat data from the peer-reviewed literature might be interested in seeing Coard (2007). Jonathan McGowan and I have been working slowly on putting together technical articles that discuss scat, trackway, feeding sign, hair and DNA evidence. Unfortunately we just haven’t yet had time to complete these: I am, after all, so very lazy.
By now you should have guessed from the photos and circumstances of discovery (viz, a BEACH) what the corpse really was. For starters, the presence of flippers and rather homodont, pointed tooth cusps demonstrate that this is a pinniped. Two pinniped species occur around the British coasts: the Harbour or Common seal Phoca vitulina and the Grey seal Halichoerus grypus. On occasion, we also get stray walruses Odobenus rosmarus, Hooded seals Cystophora cristata, Bearded seals Erignathus barbatus, Harp seals P. groenlandica, and Ringed seals P. hispida. By looking at photos of the Croyde Beach animal’s skull, most people had concluded by the end of last week that the carcass belonged to one of these species, and specifically to a Grey seal. This was, admittedly, mentioned in both the Daily Mail and Sun articles, and was also mooted as the most likely identification by Loren Coleman at Cryptomundo [Sun article shown here. Note the little section at centre-bottom: they suggest that the carcass might either be (1) a dead pinniped, (2) a big cat, (3) a mermaid, or (4) a xenomorph].
However, a rather more interesting possibility was also mentioned here and there: namely, that the carcass was not from a phocid, but an otariid. Otariids, the fur seals and sea lions, don’t occur in the North Atlantic (nor in the seas attached to it), and so far as we know they never have* (Ray 1976, Wynen et al. 2001, Deméré et al. 2003). But… escaped or released otariids have, on occasion, been present in the area. Gunter (1968) reported that feral Californian sea lions Zalophus californianus were present off the Gulf Coast of Texas (these animals might explain some sightings of the almost certainly extinct Caribbean monk seal Monachus tropicalis). In 2005, several Californian sea lions lived in the wild off the coast of Mississippi following the destruction of the Marine Life Oceanarium at Gulfport by Hurricane Katrina. The shores of Dominica were briefly visited by another escapee following the passage of Hurricane Omar in October 2008, and escaped sea lions have also been reported from the Mediterranean on occasion. Most bizarrely, a Steller’s sea lion Eumetopias jubatus lived off the Brisons (a group of small islands of the coast of Cornwall) during the 1980s. It was presumably released (the species is native to the North Pacific), but no-one knows by whom (nor what happened to it).
* The Southern sea lion Otaria byronia, South American fur seal Arctocephalus australis, Subantarctic fur seal A. tropicalis and South African fur seal A. pusillus all occur in the South Atlantic.
I became particularly interested at this point. Devon is home not only to Exmoor, big black cats, and assorted other sundry beasts, but also to the Centre for Fortean Zoology, a research group who investigate (and publish extensively on) mystery animals. They decided to investigate the Croyde Beach carcass and, having obtained permission from the land-owner, were allowed to remove the head and one flipper. Amusingly, The Sun and a few other sources now reported that parts of the carcass had – shock horror – been stolen. Anyway, thanks to Jon Downes at the CFZ I was able to obtain many excellent photos of the recovered skull and flipper, some of which you can see here [adjacent photo of skull, © CFZ].
Is it an otariid? Disappointingly, no. In otariids, the nasals only extend to the anterior margin of the orbit: in phocids, the nasals extend much further posteriorly (King 1983). Furthermore, otariids have bony lumps on the frontals (termed the supraorbital processes) that project over the orbits. Phocids lack these. The Croyde Beach skull has posteriorly extending nasals and no supraorbital processes. It is thus definitely a phocid (= earless seal).
How much further can we go? The nasal bones are short in the specimen (compared to those of other phocids like the Harbour seal) and well retracted posteriorly, hardly overhanging the narial basin. The nasal opening itself has parallel margins, whereas these are laterally concave in Harbour seals and many other phocids. The nasal cavity of the Croyde Beach skull is very deep, giving the anterior margin of the snout a steep, sawn-off look, and the fronto-nasal region of the skull is very tall compared to that of most other phocids (only grey seals Halichoerus, hooded seals Cystophora and elephant seals Mirounga have a tall fronto-nasal region like this) [see adjacent photo, © CFZ].
This combination of characters – the short, retracted nasal bones, the tall, wide, parallel-side nasal cavity, and the tall fronto-nasal region – are all absolutely characteristic of the unique Halichoerus grypus, the Grey seal.
Case closed: the carcass is definitely that of a Grey seal.
While I’m here: those of you that know a bit about mammals and about osteology will have noted that the above-listed features (short, retracted nasals and big, deep nasal cavity) are typically interpreted as evidence for a proboscis, or at least for some sort of inflatable nasal structure. In fact King (1972) noted how the osteology of Halichoerus ‘suggests it “ought” to have a nasal sac’ (p. 105). Yet Halichoerus has none of this [adjacent image from here]. Oh great, another cautionary tale for palaeontologists. As it happens, I want to talk about weird soft-tissue nasal structures some time soonish – – have been planning to do so since last July…
Refs – –
Coard, R. 2007. Ascertaining an agent: using tooth pit data to determine the carnivores responsible for predation in cases of suspected big cat kills. Journal of Archaeological Science 34, 1677-1684.
Deméré, T. A., Berta, A. & Adam, P. J. 2003. Pinnipedimorph evolutionary biogeography. Bulletin of the American Museum of Natural History 279, 32-76.
Gunter, G. 1968. The status of seals in the Gulf of Mexico, with a record of feral otariid seals off the United States Gulf coast. Gulf Research Reports 2, 301-308.
King, J. E. 1972. Observations on phocid skulls. In Harrison, R. J. (ed) Functional Anatomy of Marine Mammals. Academic Press (London & NY), pp. 81-115.
– . 1983. Seals of the World. British Museum (Natural History), London.
Ray, C. E. 1976. Geography of phocid evolution. Systematic Zoology 25, 391-406.
Wynen, L. P., Goldsworthy, S. D., Insley, S. J., Adams, M., Bickham, J. W., Francis, J., Pablo Gallo, J., Rus Hoelzel, A., Majluf, P., White, R. W. G. & Slade, R. 2001. Phylogenetic relationships within the eared seals (Otariidae: Carnivora): implications for the historical biogeography of the family. Molecular Phylogenetics and Evolution 21, 270-284.