Rage-inducing chemical on squid eggs turns males into violent thugs

In a flash, schools of male longfin squid can turn from peaceful gatherings to violent mobs. One minute, individuals are swimming together in peace; the next, they’re attacking one another. The males give chase, ramming each other in the sides and grappling with their tentacles. These sudden bouts of violence are the doing of the female squid. Males are attracted to the sight of eggs, and females lace the eggs with a chemical that transforms the males into aggressive brutes. Yesterday, I wrote about scientists who could instigate aggression in mice with pulses of light. The longfin squid do the same thing with a rage-inducing chemical [embed="610"]http://www.youtube.com/watch?v=TeeIxKf8_do[/embed] Roger Hanlon, an expert in squid, octopuses and cuttlefish, first described these sudden fights in 2003. The longfin squid (Loligo pealeii) live for less than a year. During spring and summer, females gather in large spawning sites and males compete for their attention. ...