A recent deep-sea expedition off the Cook Islands captured rare footage of faceless deep-sea creatures, specifically the faceless cusk eel (Typhlonus nasus), which inhabits depths of up to 16,730 feet where light does not reach.

The faceless cusk eel is a mysterious species living at extreme depths, with its biology still poorly understood due to the challenges of exploring such environments.

This species was discovered during an expedition with the E/V Nautilus and ROV, marking a significant breakthrough in deep-sea exploration.

The eel has a large, bulbous head filled with a light ion fluid, possibly lithium chloride, which aids in buoyancy under immense pressure.

The 2017 rediscovery revealed the largest specimen so far and clarified that the species was previously mistaken for a new discovery after being last recorded in 1873.

Ongoing deep-sea explorations, like the Nautilus expedition, aim to uncover more bizarre creatures and deepen understanding of deep-sea ecosystems, emphasizing the ocean as one of Earth’s final frontiers.

A 21-day expedition by the Ocean Exploration Trust is exploring uncharted deep-sea areas in the Cook Islands, with live streams available to the public.

The faceless eel’s anatomy includes a mouth at the bottom of its body, giving it a faceless appearance, and it feeds on detritus and small organisms on the seafloor.

Juvenile faceless eels may have eyes beneath their skin, but adults are completely eyeless, with their mouths located at the bottom, contributing to their eerie appearance.

This discovery underscores the vast unknown biodiversity of the deep ocean and the potential for uncovering new species and adaptations in unexplored habitats.

Faceless eels lack eyes as an adaptation to darkness, with juveniles showing small, hidden eyes that may be remnants of an ancestral trait.

The species was first discovered near Australia in the 1870s, then went missing from scientific records for over a century before being rediscovered in 2017 during another research voyage.