Most squids have eight arms and two longer “feeding” tentacles. The tips of the tentacles, which are often broader and armed with suckers or hooks, are known as “clubs.” Such squids hunt by rapidly extending their tentacles and then grabbing prey with their clubs. The squids also use the tentacles to carry captured prey to their mouths.
The deep-sea squid Grimalditeuthis bonplandi seems to use a very different feeding strategy. A slow swimmer with a weak, gelatinous body, its tentacles are long, thin, fragile, and too weak to capture prey. Unlike any other known squid, its tentacles do not have any suckers, hooks, or photophores (glowing spots).
Until just a few years ago, the marine biologists had only seen specimens of G. bonplandi that were dead or dying after having been captured in deep-sea trawl nets. However, using video from underwater robots known as remotely operated vehicles (ROVs), the authors of the recent paper were able to study how these squids behave in their native habitat, 1,000 to 2,000 meters (roughly one mile) below the ocean surface.