Vampire squids, known for living at a slower pace than other squids, have a unique reproductive strategy, setting them apart from all other living cephalopods, and allowing them to live a relatively longer life, researchers said in a new study, published in the journal Current Biology on Monday.

Unlike other squids and octopuses that have only one reproductive cycle before they die, vampire squids, which tend to float, rather than swim, experience dozens of egg-making cycles in their lifetimes -- a pattern of multiple spawning more common among fish, the researchers said in the study. This, they said, suggests that these deep-sea creatures -- found at ocean depths between 1,640 feet and nearly 9,840 feet -- may live several years longer than coastal squids.

“Their slow mode of life seems insufficient to support one big reproductive event, unlike other coleoid cephalopods,” Henk-Jan Hoving of the GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany said in a statement. “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.”

While going through vampire squid collections dating back to the 1960s and 1970s at the Santa Barbara Museum of Natural History, Hoving and his colleagues found that many of the female vampire squids had spawned, but still had the ability to produce more eggs as they were in a reproductive resting phase.

Among 40 vampire squid females tested by the researchers, one female had released at least 3,800 eggs before her death, but still had about 6,500 viable immature egg cells for future spawning. If an average batch size is 100 eggs, the female had already spawned about 38 times, with eggs in reserve for another 65 times of spawning, the researchers said.

Based on the latest findings, the researchers think that vampire squids’ adult stage lasts up to eight years, with even longer total lifespan, while most other squids and octopuses do not live more than two years, Live Science reported.

“We need to enhance our knowledge of deep-sea pelagic organisms and the system they are part [of]… A better understanding of this unique marine ecosystem will eventually allow for better development of management and conservation strategies,” Hoving said in the statement.