Do Lobsters Really Mate for Life?

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It's a pop culture trope that mated lobsters stay together until they die. But is it true?

Nope. While plenty of animals practice long-term monogamy, lobsters are not among them. Lobsters actually mate by a weird system of serial monogamy. It's not exactly a one-night stand, but it's not a lifelong commitment either. Instead, a bunch of females take turns having a fling with the local dominant male that lasts a week or two and, if they're not happy with the amount of genetic material he's provided, then seek a little extra action.

It works like this: A female lobster who's ready to mate (which they can only do right after they've molted) hangs out near the den of the local dominant male and fans her pheromone-laced urine into his home. This relaxes the male, making him less aggressive and more receptive to mating. Then there's a brief courtship, and the male allows the female into his den.

Anywhere from a few hours to a few days later, the female slips into something a little more comfortable by shedding her exoskeleton. (Shacking up with the neighborhood tough guy guarantees her protection during this vulnerable time.) The pair mates, and the male deposits his sperm in the female. Once her new shell has hardened a week or two later, she takes off, and another female can have her turn. Often, the females in an area will stagger the timing of their molts to make their reproductive conga line more efficient. As soon as one female is done with the stud, the next one is already waiting to pee on his doorstep.

Sometimes, the male doesn't provide enough sperm to fully fertilize all of a female's eggs. In these cases, she'll leave before her new shell finishes forming to find and mate with another male (or males) until she collects enough sperm. Usually this requires just an extra dalliance or two, but as many as 10 have been reported.

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