Southern elephant seal mothers have only one thing on their mind after weeks marooned on beaches nursing their pups: getting back into the ocean to feast on lantern fish and squid. Yet, no one was sure how the ravenous predators locate victims in the inky depths.
Pauline Goulet from the University of St Andrews, UK, and PI Mark Johnson suspected that the eerie bioluminescent glow produced by many creatures in the deep ocean might have something to do with it.
“Bioluminescent organisms are the main source of light (80%) in waters deeper than 500 m,” says Goulet. These animals produce two forms of light — a continual dim glow for camouflage from beneath and dazzling flashes, possibly to distract predators — and the duo wondered whether ravenous seals might capitalize on the creatures revealing themselves. Or, could the feisty prey buy themselves time by dazzling their attackers to make a getaway?
Curious to know how these games of cat and mouse play out beneath the waves Goulet, Christophe Guinet from the Centre d’Etudes Biologiques de Chizé, France, and Johnson decided to catch elephant seals in the act while pursuing their pyrotechnic victims. They publish their discovery that bioluminescent squid and fish flash at predatory elephant seals when under threat to disorientate the attacker to buy precious time to escape. The researchers publish their discovery in Journal of Experimental Biology.