Rival Canadian and American boffins went head to head this week, battling to resolve one of the most hotly-disputed scientific questions of recent times. That is of course: are hippos a type of amphibious whale, or are they in fact a freshwater pig?
Heading up the porker-potamus school is Professor J G M Thewissen of the Northeastern Ohio College of Medicine, armed with an extinct Indian underwater-pig fossil.
It seems that 48 million years ago, "Indohyus" hydro-hogs roamed India, feeding on dry land but making their homes in the water. Thewissen and his crew of scientists analysed the bones of a fossilised Indohyus and apparently concluded that the subcontinental submarine swine was closely related to whales.
This, as anyone would realise, could mean that the shore-dwelling branch of the whale family was the Indohyus, not the hippopotamus. Hippos, then, could actually be relatives of regular landgoing piggies - perhaps a branch of the family which simply let bathtime get a bit out of hand.
But that's all a load of fossilised pig knuckles, according to Professor Jessica Theodor of Calgary Uni. She and her academic homies have administered a stinging scientific bitchslap to Thewissen, using DNA evidence. Theodor's crew reckon that in fact hippos are whales, not pigs.
The feisty Canadian prof is plainly spoiling for a fight, and explicitly pooh-poohs the porker-potamus idea.
"What Thewissen is saying is that Indohyus is the closest relative of whales - and we agree. Where we think he is wrong, is that he is saying that that hippos are more closely related to true pigs than they are to whales," she says. "This contradicts most of the data from DNA from the last 12 or 13 years. Those data place hippos as the closest living relative to whales."
Thewissen's hog-hippo theory was aired in prestigious boffinry mag Nature back in December 2007. Now Theodor has counterpunched in the same heavyweight journal, setting out the case for her rival Mobypotamus theory in an article published yesterday.
The word hippopotamus actually means "river horse" or similar, but it seems that's way out of court: horses aren't even in the running genealogy-wise. The name's understandable, however, as the irascible river-dwelling artiodactyls eat grass and are bloody nippy when they feel like it. It has been claimed that the grumpy creatures, which weigh as much as a Humvee, "kill more people in Africa than any other animal except mosquitos".
Nonetheless humanity seems to be doing much better in the war against hippos than it is against mosquitos, perhaps accounting for the fact that there are no plans to vaporise the big fellows en masse using airborne laser disco cannon as there are with the bloodsucking insect pests. Hippos are now listed as "vulnerable" to extinction by the International Union for Conservation of Nature.
The brawling hippo genealogists may find their debate becoming literally academic, should their subject African population continue to dwindle. However, in more positive developments, it appears that a colony of hippos imported to Latin America years ago as pets by recreational-chemicals kingpin Pablo Escobar are multiplying in fine style.
Thewissen's responding pooh-pooh of Theodor's initial pooh-pooh also appears in Nature, and seems to claim that he never said hippos were pigs actually, so there. ®