Sex at close to 10,000 feet below the ocean’s surface happens slowly but frequently for at least some denizens of the deep.

Since these creatures — vampire squid — mate at a different pace than other squid and their related species do, a new study reveals how unique reproductive strategies can be at tremendous ocean depths.

Antarctic Marine Life Mapped in New Atlas: Photos

The new study is published in the latest issue of the journal Current Biology.

“We know very little about deep-sea organisms and their life-cycle patterns, in particular in the water column of the deep sea,” lead author Henk-Jan Hoving of the GEOMAR Helmholtz Center for Ocean Research Kiel said in a press release. “The patterns we know from coastal and shallow-water organisms may not apply to deep-sea species.”

Vampire squid got their name, not because they feast on blood, but because of their big red eyes and darkly colored cloak-like webbing.

Hoving and his team were going through the vampire squid collections from the 60s and 70s at the Santa Barbara Museum of Natural History, when they noticed something unexpected.

Video: Giant Squid: King of the Ocean

Many of the female vampire squid had spawned, but they had no ripe or developing eggs and were in a reproductive resting phase. This is unheard of for other squid, which reproduce all at once late in their lives and that’s it.

Here is video showing how another squid species, Pholidoteuthis adami from the Gulf of Mexico, mates:

The researchers also investigated female vampire squid. One had released at least 3,800 eggs, yet still retained 6,500 viable oocytes (immature reproductive cells) for future spawning. Assuming an average batch size of 100 eggs, the researchers suggest that this one female had already spawned about 38 times, with eggs in reserve for another 65 or so spawning episodes.

That means vampire squid could have about 100 times more sex than other squid do!

Life at incredible ocean depths goes at a slow pace, however. Vampire squid don’t swim so much as float. They also must survive with very little oxygen, and their diet is a very low calorie one, since they mostly eat zooplankton and organic debris.

Vampire Squid Thrive on Feces and Ocean Debris

Given this life in the slow lane, and the findings about vampire squid eggs, the researchers believe that the squid alternate between reproductive and resting phases.

"We need to enhance our knowledge of deep-sea pelagic organisms and the system they are part , since the pelagic deep sea is the largest living space on the planet," Hoving said. "A better understanding of this unique marine ecosystem will eventually allow for better development of management and conservation strategies."

Image: Illustration of a vampire squid. Credit: Sitron, Wikimedia Commons