They keep growing until they die. If they live long enough they get so big they either can't get enough food or oxygen and die.

They have urinary ducts in their eyes and when they meet other lobsters they piss on each others face. If they have fought in the last week or so the loser backs down. If not they fight.

The biggest male lobster knows where the others live and once a week visits the other lobsters. Pisses in their face and then beats them up.

When a female enters estrus she goes to the biggest lobster's den. He then beats her to help her molt. When her shell is removed they mate.

She is allowed to stay for a few days during the vulnerable period when her shell regrows and hardens. Unless another female comes by. The he kicks her out and the new girl moves in after mating.