Vampire squid are named for their lives in utter darkness up to 3,000 metres beneath the oceans, not for sucking blood – they don’t. They survive with little oxygen and a low-calorie diet of zooplankton and detritus.
To cope with lives at such great depths, they have the slowest metabolic rate of all deep-sea cephalopods.
Now scientists have found something else unique about the mysterious creatures – their sex lives.
Researchers reporting in the journal Current Biology have found that, while other squid reproduce all at once late in their lives, vampire squid appear to alternate between reproductive and resting phases in a pattern of multiple spawning more common among fish.
“Their slow mode of life seems insufficient to support one big reproductive event, unlike other coleoid cephalopods,” says Henk-Jan Hoving of GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany. “Perhaps it is therefore that vampire squid return to a gonadal resting phase after spawning, and presumably start accumulating energy for a new reproductive cycle.”
Hoving and his colleagues were led to the discovery quite by accident as they were going through vampire squid collections dating back to the 1960s and 1970s at the Santa Barbara Museum of Natural History. They noticed something unexpected along the way: many of the females had spawned but had no ripe or developing eggs and were in a reproductive resting phase.
“We know very little about deep-sea organisms and their life-cycle patterns, in particular in the water column of the deep sea,” Hoving says.
“The patterns we know from coastal and shallow-water organisms may not apply to deep-sea species.”