Sunday, September 19, 2004

The Sex Secrets of Lobsters

From an awesome interview with Trevor Corson, the author of "The Secret Life of Lobsters," at where else but (get an anual membership through me for only $15!!) :

Did you find out more from the scientists than you expected?

After two years of working on a lobster boat I thought I knew a lot about lobsters, but when I started researching the book and talking to the scientists who study lobsters for a living, I had no idea.

The most amazing thing is how the lobsters socialize, communicate, and their mating ritual. It turns out that lobsters do most of their interpretation of the world and their socializing through their sense of smell. Their nose is actually a pair of little flickable antennules, or mini-antennae. They're packed with chemo receptors and they flick them in the water to detect odors, like sniffing, and if they're in a good current they can hold them up like rabbit ears and pick up all the chemicals in the water.

They also have this little interesting feature of their anatomy where they have a big bladder in their head and they piss out the front of their head. So they're constantly pissing in each other's faces. When a female wants to seduce a male, she comes by the door of his apartment and he sits inside and pisses out the door at her. If she likes the smell she comes by and sticks her head inside his apartment and pisses back at him.

Um, when you say apartment ...?

They live inside little rock hollows, basically, and they're very attached to their homes. That's not to say that they don't move from one to the next, but they're very defensive creatures despite all the armor. They really like to hunker down and they have a strong preference for backing into tight places with their claws out and ready so they can defend themselves.

So when scientists started studying the mating habits, there was very little information about crustacean mating and how it worked. The anatomy had been investigated for a long time. At first the scientists couldn't figure out how lobsters mated and no one was sure if the male lobster had a penis at all, and then it turned out that it had two.

That's real vindication.

Yeah, so they knew the anatomy, but they still couldn't figure out how the social part worked. Normally lobsters hate each other. If you put a male and female lobster in a tank with each other they start fighting right away and try to kill each other. In nature they have a pretty complicated set of procedures for interacting with each other that are designed to actually avoid real injury, so that a smaller lobster can immediately tell that a bigger lobster is dominant and get out of the way. But if the lobsters are evenly matched in a tank they just continue fighting and the whole thing escalates.

So one of the scientists I write about, Jella Atema, thought the female lobster might be emitting a pheromone to attract the male but it turns out to be exactly the opposite. They did these experiments where they set up a social situation in a 20-foot tank. The males would fight with each other to figure out who the dominant male was, and once he was proven dominant he would go around and beat up all the other lobsters every night. All the lobsters in the neighborhood would be dealt a daily dose of humiliation, both males and females. He'd kick them around and then go back and hang around his shelter, which was the best shelter in the tank, of course.

What happened then is that the females started to take up residence nearby and they would come by his shelter. Then one of them began an elaborate social ritual where she'd come calling to the door every day and eventually he would let her inside the shelter. Then she actually moved in, and it turns out she was ready to shed her shell at that time. So within 15 or 30 minutes of her molting the male approaches and turns her over and they copulate while she's soft. Then after about a week, once her shell has hardened up again, she leaves without a backward glance. So they've pair-bonded for about two weeks. And then? The next female lobster shows up and moves in with the dominant male. And this goes on in sequence. The female lobsters are keeping tabs on each other to figure out who's mating with the dominant male, and they wait until one of their sisters has done her business and then the next moves in. So they all take turns. It's called serial monogamy.

It's funny, sometimes people use specific mating habits of animals to prove a certain point about human sexuality, though I can't imagine what group would claim lobsters as their example.

The Mormons might like it. But it's not all at once. It's in sequence, you wouldn't be able to keep a harem going. The male just waits at home once he's proven his dominance by beating up everyone every night, which really arouses the females. And it turns out they're recognizing his smell, because he's pissing in their faces all the time while they're fighting.

They're violent little creatures. What's with all the aggression? And the pissing? They look so passive and harmless floating in those restaurant tanks.

Jella Atema set up a boxing ring in order to study lobster fights, and when he staged rematches on consecutive nights, the loser immediately recognized his former opponent and backed down, forfeiting the fight. It wasn't that lobsters had become cowards -- if the loser was paired with another lobster he would fight aggressively again. So something was going on and the lobsters were recognizing individual opponents that had beaten them before. Blindfolding the lobsters didn't make any difference. So the scientists catheterized some lobsters, put these little tubes over their urine slots on their face and made a little urine bottle and measured outflow.

It turns out that the lobsters were accompanying their most punishing blows with intense squirts of piss in each other's faces. The scientists actually charted the results, so clearly the smell is what they pick up on. The funny thing is that the winner was almost always the lobster that pissed first, the first one off the draw, like down at the OK Corral, but in this case whoever pissed first wins.

They realized that this pissing was going on in the bedroom, too. When the male lobster was fighting with everyone in the tank he was pissing in everyone's face and when the females would come by they would piss in his face. The scientists think that the females were also pissing a drug at the male when they're getting ready to molt. So after the females are satisfied that he's the toughest one they would drug him to tone down his aggression, which puts him in the mood for courtship and then the females convince him to mate. So the males are out there fighting, but the females really choose which one they mate with. They're in charge and they have this sisterhood deal where they're basically cooperating so they all get to nail this one lobster who they've chosen.

In terms of simple outright aggression, lobsters are brutal. One guy in New Hampshire did an experiment to see if lobsters preyed on each other. He tethered a juvenile lobster to the bottom of the shallows so he couldn't get away. Very quickly big lobsters showed up, and when they figured out that he was helpless, they attacked the young lobster, crushed him, and then ate him.