A REVEALING GESTURE: HOMOTHERIUM PERFORMING “FLEHMEN”
Paleontologists are thoroughly familiar with the shape and disposition of the teeth of the sabretooth Homotherium, and could never confuse them with those of a modern big cat. But when the animal was alive, soft tissue covered the maxilla and teeth, and obscured the differences. Obviously the proportions of the head, with a massive muzzle and a straight dorsal outline, were clearly different from those of a lion.
But if we could see Homotherium performing the “flehmen” gesture, then the depth of the differences with any modern big cat would become truly evident. During “flehmen”, cats pull back the lips in a grimace and elevate the snout, in order to allow odoriferous particles in the air to reach the vomeronasal organ, located back in the palate. They often do it in reaction to finding the odour of another cat, and they can judge, for instance, if a female is in oestrus.
But for the casual observer, the Flehmen response is a wonderful way to see the shape of the cat’s dentition, and in the case of Homotherium, it would reveal that the animal was “all incisors”. Effectively, while the incisors of a lion are relatively small and arranged in a neat row closely in front of the canines, those of Homotherium were disproportionately large and projecting in an arch. So spectacular were the incisors that the canines themselves would not impress us too much, especially compared to those of dirktooth cats like Smilodon.
In this reconstruction of Homotherium doing “Flehmen” you can see the large size of the incisors and how they porject far in front of the upper canines. In the lower jaw, the the incisors are so large that there is little difference with the lower canines.
Another advantage of the Flehmen response is that the animals keep it for several seconds while slowly moving the head sideways, thus allowing us to observe the teeth at leaisure. Artists often prefer to depict the animals in aggresive situations, where bared teeth are part of a violent encounter and where, in real life, we would only see a brief flash of the creature’s weaponry. But if I were one of the hominids that shared the environments of Pleistocene Europe with Homotherium, I would far prefer that the animal I met was doing flehmen rather than snarling in aggression. That way there would be greater chances that the impressive array of Homotherium‘s teeth wasn´t the last thing I saw in this world!