difficult. This species is found in the mesopelagic zone of the ocean at depths down to 1600 metres. Spawning takes place on the bottom and the paralarvae live at even greater depths, down to 3000 metres. Adults often live in groups at depths of 200 to 300 metres, often in areas where shrimps are found. Predators that feed on this squid include dolphins (Grampus griseus), the velvet belly lantern shark (Etmopterus spinax), the blackmouth catshark (Galeus melastomus), the small-spotted catshark, (Scyliorhinus canicula), the swordfish (Xiphias gladius) and tuna (Thunnus alalunga). Heteroteuthis dispar can be bioluminescent, emitting light from photophores containing bacterial symbionts. A large photophore is found on the underside and contains two pores through which the luminescent material is extruded. An iridescent shutter cover helps to filter and control the light. The squid can also secrete bioluminescent mucous from glands near the ink sac. This can be released into the water through the funnel and the glowing cloud is believed to blind or confuse predators for long enough for the squid to make its escape. References Bobtail squid Cephalopods described in 1844 Marine molluscs of Europe Cephalopods of Europe