Rare, Wimpy Deep-sea Squid Catches Prey with a Wiggle [VIDEO]
Marine researchers have unraveled the mystery of a wimpy species of deep-sea squid, capturing the creature on video for the first time and discovering how the squid, which lacks the muscular tentacle arms his brethren use to capture prey, feeds itself in a way unlike any other squid.
Scientists have wondered for years how Grimalditeuthis bonplandi captures prey. Like all squid, G. bonplandi has two long, thin tentacles and eight arms. But G. bonplandi has tentacles unique among squid; its extremely thin and fragile stalk lacks the sticky suckers, hooks or glowing spots (photophores) which accessorize the tips or clubs of other squids
Another unusual trait among G. bonplandi is its inability to extend and retract its tentacle stalk as do other squids. Instead, the squid moves its tentacle stalk by wriggling the club head.
The squid's unique tentacle anatomy has led researchers to believe this species captures its prey in a manner similar to crustaceans and fish.
G. bonplandi apparently makes up for its unadorned tentacles by waving them in the deep ocean in a way that resembles the swimming movements of small prey animals such a shrimp, worms and some fish.
"These tentacle club movements superficially resemble the movements of small marine organisms and suggest the possibility that G. bonplandi uses aggressive mimicry by the tentacle clubs to lure prey, which we find to consist of crustaceans and cephalopods," the researchers wrote to the abstract to their paper on the find, which was published Tuesday in the journal Proceedings of the Royal Society B.
The researchers suspect one or all of three things occur when the squid wriggles its tentacles: either it stimulates bioluminescence in the surrounding water, which will act as a sort of magnet for any creatures swimming nearby, the wriggling will create a hydrodynamic wake which will attract prey, or the low-frequency vibrations created by the wiggling will act as a lure for prey.
Exactly how the squid then eats its prey is still being debated. Study co-author Bruce Robison, a deep-sea ecologist with the Monterey Bay Aquarium Research Institute (MBARI), speculates that the squid shoots its entire body forward towards the prey which is lured by the bare tentacles.
"When you go fishing, you like to have really thin fishing line," Robison told National Geographic. "If we view this as a lure at the end of a fishing line, having a really slender thread out to your bait makes sense."