In other words, previous losers lose or refuse to fight with a new opponent. In the case where losers are pitted against other losers, no displays or fights occur. Usually the dominant or subordinate status only lasts until the animal molts. Then, if a subordinate molts first, survives, and becomes larger than the dominant, it will often become the new dominant animal. It is currently believed that these seemingly long-term changes in status and behavior are determined by the level of two hormones known as serotonin and octopamine.
Winners have higher blood levels of serotonin , while losers have higher levels of octopamine.
If a lobster who has previously lost a fight is injected with serotonin, it becomes extremely belligerent and will attack lobsters much larger than itself. Studies such as these imply that aggressive behavior may have a hormonal component, and the lobster is currently being used as a model to better understand human aggression. Material provided in this document is not to be cited or used without permission . Copyright by The Lobster Conservancy, 1998.