Consider Their Claw Walk
From History Today:
Aristotle was rarely puzzled, but even he had to admit that lobsters were weird. After leaving the court of Hermias of Atarneus in around 340 BC, he had spent several years studying the creatures on the island of Lesbos. He had watched fishermen bringing in their catch, talked with travellers from far-off lands and examined specimens for himself. In fact by the time he left Lesbos to take up a job in Macedon in 343 BC he had become something of an authority on them. With the keen eye for ‘family’ resemblances which was to become the hallmark of his scientific method, he had spotted that, in most important respects, they were no different from any other crustaceans. Like crabs and crawfish, he wrote in the Historia animalium, they have ‘hard and shelly parts on the outside, where the skin is in other animals, and the fleshy parts inside’; they have ‘little flaps’ on their bellies, where the females deposit their spawn; they have two mandibles on either side of the mouth; and they have a peculiar organ called ‘mytis’ or ‘poppy juice’. What made them unusual, however, were their claws. Although plenty of other species also had claws, lobsters’ were completely different. Not only was one of their front claws bigger than the other, but they also had a set of much smaller claws on two pairs of their legs. This was peculiar enough in itself. After all, why did they need six claws, rather than just two? And why in so many different sizes? Strangest of all, however, was what they did with them. Instead of using their secondary claws like the others, lobsters appeared to walk on them.