🌊 #1 answers: Deep Sea Day

Round bite marks left by the small cookiecutter shark have been found on submarines and undersea cables.

It gouges neat round plugs out of much bigger animals, as if using a cookie cutter.

“Marks made by cookiecutter sharks have been found on a wide variety of marine mammals and fishes, and on submarines, undersea cables, and human bodies.”

The stoplight loosejaw is a deep-sea fish that can give off both red and blue light from its body.

Most deep-sea animals can't see red light, so it works like a secret searchlight.

“Another unique adaptation for this species is its ability to produce both red and blue bioluminescence.”

Despite its spooky name, the vampire squid drinks no blood and feeds on drifting scraps of dead matter instead.

It was named for its dark colour and cape-like webbing, not its diet.

“The name Vampyroteuthis was reportedly inspired by its dark colour and cloaklike webbing, rather than its habits — it feeds on detritus, not blood.”

The dumbo octopus is named after a cartoon elephant because of the two ear-like fins sticking out above its eyes.

It flaps those fins to swim gently through the deep.

“The name "dumbo" originates from their resemblance to the title character of Disney's 1941 film Dumbo, having two prominent ear-like fins which extend from the mantle above each eye.”

Yeti crabs get most of their nutrients from bacteria that grow on their own hair-like bristles.

They live by hydrothermal vents, where these bacteria thrive on chemicals in the water.

“Yeti crabs receive most of their essential nutrients from chemosynthetic episymbiotic bacteria which grows on hairlike setae.”

A giant squid's eye can be at least 27 centimetres across, among the largest eyes of any living animal.

Big eyes catch more of the faint light found in deep water.

“It also has the largest eyes of any living creature except perhaps the colossal squid—up to at least 27 cm (11 in) in diameter, with a 9 cm (3+1⁄2 in) pupil (only the extinct ichthyosaurs are known to have had larger eyes).”

When a hagfish releases its slime into seawater, the goo swells to 10,000 times its size in under half a second.

The slime can clog the gills of a predator trying to bite it.

“When released in seawater, the slime expands to 10,000 times its original size in 0.4 seconds.”

Osedax, the so-called zombie worms, have no mouth or gut and rely on microbes living inside them for food.

They settle on sunken whale bones and dissolve them with acid to get at the fats inside.

“Like other siboglinids, Osedax lacks a mouth, gut, or anus, and instead depends on colonies of endosymbiont microbes housed inside a trophosome for nutrition.”

Greenland sharks are estimated to live at least 272 years, and one was thought to be about 392 years old.

Scientists radiocarbon-dated tissue from the eye lens. The oldest estimate is 392 years, give or take 120.

“It is estimated that the species has a lifespan of at least 272 years, with the oldest individual estimated to be 392 ± 120 years of age.”

The scaly-foot snail builds iron sulfide into its shell, something no other living animal is known to do.

It lives at hot hydrothermal vents in the Indian Ocean, wearing a shell partly made of metal.

“This species is considered to be one of the most peculiar deep-sea hydrothermal-vent gastropods, and it is the only known extant animal that incorporates iron sulfide into its skeleton (into both its sclerites and into its shell as an exoskeleton).”