Inefficiency in bioluminescent cells may let sea creature mask itself
© 2009 MBARI
A sloppy light system may be just what a squid needs to hide from predators. Bioluminescent cells in some glass squid work in a surprisingly inefficient way — leaking a lot of light rather than fully channeling it, a new study suggests.
Glass squid have largely transparent bodies, helpful for inconspicuous swimming in deep open water. Marine predators often scan the waters above them for the telltale silhouettes of prey blocking sunlight, but there’s little to betray a glass squid — except for a few notable features such as the shadow-making eyes on its head.
Underneath those eyes, squid in the genus Galiteuthis grow silvery patches of cells that act as undersurface bioluminescence, a camouflage technique that has evolved in various marine creatures, making their shadows less conspicuous to hunters below.
Biophysicist Alison Sweeney of the University of Pennsylvania in Philadelphia had hypothesized that the cells, called photophores, act