Male sea spiders are stay-at-home dads who protect the female's eggs, researchers have discovered.

Conservationists from the University of Hawai (UH) at Manoa claim they have finally cracked the long-hidden mysteries of giant sea spider reproduction in Antarctica.

After more than 140 years of speculation, the team's recent expedition to the remote continent shed light on the behaviour of the enigmatic creatures, with potential implications for marine life and ecosystems worldwide.

Sea spiders, scientifically known as pycnogonids, are spider-like invertebrates found in aquatic environments globally.

While most species are small, Antarctic sea spider varieties boast leg spans exceeding a foot, in what scientists term as 'polar gigantism.'

Despite historical research going back over a century, the reproductive habits of these Antarctic giants remained elusive until now.

Lead researcher and UH Mānoa School of Life Sciences Professor Amy Moran described the team's remarkable fieldwork in Antarctica, where they observed two mating groups of sea spiders depositing thousands of eggs.

Unlike typical sea spider species, one parent, likely the father, protected the eggs for several months until they hatched into tiny larvae.

Professor Moran said: 'In most sea spiders, the male parent takes care of the babies by carrying them around while they develop.

'What's weird is that despite descriptions and research going back over 140 years, no one had ever seen the giant Antarctic sea spiders brooding their young or knew anything about their development.'

This never-before-seen behaviour unveiled new insights into the creatures' life cycle.

Published in Ecology in February 2024, the researchers' findings represent a significant breakthrough in understanding Antarctic marine ecosystems.

Renowned Antarctic biologist Lloyd Peck, from the British Antarctic Survey, commended the study's significance in advancing knowledge of polar marine life.

The UH team's remarkable was captured in a video, showcasing their up-close encounters with Antarctic sea spiders and the challenging fieldwork conducted under the continent's icy waters.