Discovered in the deep: the incredible fish with a transparent head

Discovered in the deep: the worm that eats bones

In the ocean’s shadowy twilight zone, between 600 and 800 metres beneath the surface, there are fish that gaze upwards through their transparent heads with eyes like mesmerising emerald orbs. These domes are huge spherical lenses that sit on a pair of long, silvery eye tubes – hence its common name, the barreleye fish (Macropinna microstoma).

The green tint (which actually comes from a yellow pigment) acts as sunglasses, of a sort, to help them track down their prey. There’s nowhere to hide in the open waters of the deep ocean and many animals living here have glowing bellies that disguise their silhouette and protect them – bioluminescent prey is hard to spot against the dim blue sunlight trickling down. But barreleyes are one step ahead.

Their eye pigment allows the fish to distinguish between sunlight and bioluminescence, says Bruce Robison, deep-sea biologist at the Monterey Bay Aquarium Research Institute in California. It helps barreleyes to get a clear view of the animals trying to erase their shadows.

The barreleye’s tubular eyes are extremely sensitive and take in a lot of light, which is useful in the inky depths of the twilight zone. But Robison was initially mystified that their eyes seemed fixed upwards on the small spot of water, right above their heads.

“It always puzzled me that their eyes aimed upward, but the field of view did not include their mouths,” says Robison. Imagine trying to eat scraps of food floating in front of you, while fixing your eyes on the ceiling.

But, after years of only seeing dead, net-caught specimens, Robison and colleagues finally got a good look at a living barreleye through the high-definition cameras of a remotely operated vehicle. “Suddenly the lightbulb lit and I thought ‘A-ha, that’s what’s going on!’,” he says. “They can rotate their eyes.” This means the fish can track prey drifting down through the water until it is right in front of their mouth.

First Photos: Weird Fish With Transparent Head

Seeing a barreleye alive in the deep, Robison saw something else that scientists had previously missed. “It had this canopy over its eyes like on a jet fighter,” he says, referring to the transparent front part of the barreleye’s body, which had been torn off all the specimens he had previously brought to the surface.

He thinks this canopy probably helps protect their eyes as they steal food from among the stinging tentacles of siphonophores – animals that float through the deep sea in long, deadly strings, like drift nets.

Barreleyes have been found with a mix of food in their stomachs, including siphonophores’ tentacles, as well as animals that siphonophores feed on, including small crustaceans called copepods. Their tactic may be to swim up to siphonophores and nibble on the small prey snagged in their tentacles, using the transparent shield to protect their green eyes from stings.

But encountering barreleyes in the wild is not easy. In his 30-year career, Robison says he has only seen these 15cm-long fish alive maybe eight times. “We do spend a lot of time exploring down there, so I can say with some confidence that they’re quite rare,” he says.

Relative Articles

None found

Related Posts

The dog was abandoned in the middle of the road, it ran like it was flying after its owner’s car

Dogs are the most loyal animals in the world. Once they realize that you are their owner, they will follow you for life. Even if you are…

A week after the dog went missing, the owner received a call from a stranger: “Your dog is at the North Pole

If you get a call and the person on call tells you that your dog has been missing for a week now has been found in the North…

The little sheepdog is an “intern”, short-legged and follows the flock of sheep, “wait for me”

A video of a tiny sheepdog starting training immediately made millions of viewers flutter. Looks small, stupid but very hard-working, with short legs and trotting after a large…

The blind dog found guidance from his special friend, a touching story

 Blind Staffie Finds A Guide In His Forever Friend Jess Martin fell in love with an adorable Staffordshire named Amos who was born blind while volunteering at…

Two-Legged Stray Momma Cares For Her Homeless Family

We ƙnσw animals are resilient, and many times they adaρt tσ their enνirσnment and surνiνe as best as they can. After all, there are milliσns σf hσmeless…

The mountain climbing dog was so tired that he almost fainted. When he saw the rescue team carrying a stretcher coming to pick him up, he said: “Luckily, you guys are here, I’m so tired.”

On a beautiful day, the man took his 50kg dog hiking. Because he had the day off, he decided to take his dog on a picnic to…