Top 5 Creepiest Crustaceans of the Deep Sea

Yeti crabs, whale louse, Japanese spider crabs, remipedes, and coconut crabs are all creepy crustaceans that are the stuff of nightmares!

Oct 6, 2023By Natasha Elder
creepy crustaceans

From massive spider-like crabs that skitter across sandy ocean floors to small stomach-churning parasites that feast on live whales, the world of crustaceans can be a remarkably creepy one. In this blog post, you’ll discover the spine-chilling underwater world of the creepiest crustaceans known to man.

1. Japanese Spider Crabs

japanese spider crab huge
Image credit: Fact Animal

First up is the Japanese spider crab, which holds the title of the largest crustacean in the world. These long-legged creatures can have an incredible leg span of up to 12.1 ft (or 3.7m!) from claw to claw. They can live up to 100 years, and it doesn’t matter if they lose a leg or two during this century as their legs can regenerate. Japanese spider crabs are omnivores who will feast on anything from algae to decaying fish flesh. Yummy.

Can you even imagine bumping into one of these giant guys in the wild? Though they’re native to the waters of Japan, overfishing poses a problem to the Japanese spider crab species, and it’s not easy to find them in the sea. If you want to see these giant legs up close, the best aquariums in the USA will be your best bet (specifically Tennessee Aquarium, Shedd Aquarium, and Monterey Bay Aquarium have great tanks – with the latter featuring a live crab cam dedicated to the Japanese spider crab!)

2. Whale Louse

whale louse microscope cyamus boopis
Image credit: Wikipedia

Have you ever wondered why some whales have spots or patches of white on their skin? The answer is creepier than you could have imagined: those patches of white spots are not birthmarks or unique biological patterns, but instead, they are large groups of parasitic crustaceans known as whale lice. Despite their name, whale lice aren’t true lice. Whale lice are crustaceans that are closely related to the skeleton shrimp (which is also pretty creepy!) and are considered commensal external parasites.

These parasites live on several parts of the whale – from its nostrils to its eyes, and from its genital folds to its back. A whale louse will slowly feast on the whale’s skin and tissue for the entirety of its life. Interestingly, whale lice are the second most common parasite that hitchhikes on whales, with another type of crustacean – barnacles – claiming first prize.

3. Yeti Crab

Yeti crab
Image credit: Woods Hole Oceanographic Institution on X

What do you call a crab with no visible eyes, a layer of long silky blonde fur, and disproportionately large yet symmetrical claws? Why it’s the yeti crab, of course. First discovered in 2005, these ghostly deep sea creatures inhabit the vents found in the midnight zone of the deep sea.

Unsettling appearance aside, another creepy fact about the yeti crab is its fascinating ability to – essentially – grow its own food. The yeti crab’s setae, which is the proper name for the fur-like bristles found on its arms, is the perfect breeding ground for filamentous bacteria – which is this strange crustacean's primary food source. In other words, the yeti crab farms its own food. Food in the deepest zones of the deep sea is scarce, so the yeti crab’s unique feeding habits could be an example of deep-sea adaptations.

4. Coconut Crabs

giant coconut crab speckled
Image credit: Scuba Diver Mag

Next up is a crustacean that is known for ripping through coconut husks with ease, climbing trees at remarkable speeds, and being one of a few surprising apex predators. With branchiostegal lungs instead of gills, it’s the largest terrestrial arthropod alive. This means that it’s the biggest crab outside of the sea – that’s right, you can quite easily encounter this bird-eating behemoth on beaches or forests in the Gambier, Caroline, Christmas, or Pitcairn Islands area.

On top of the birds mentioned above and the obvious (coconuts), these creepy crustaceans will eat other crabs, smaller creatures such as rats and hatchlings, carrion, and a variation of nuts, pith, and seeds – basically whatever it can get its gigantic pincers on! Coconut crabs can live up to the ripe old age of 60 years, are known to steal garbage, and are technically unable to survive underwater for more than an hour.

5. Remipedes

remipede underwater centipede venomous crustacean
Image credit:

With its long twitching antennae, hundreds of scuttling legs, and hard exoskeleton body, what could be creepier than a centipede? How about one that swims? Enter the remipede: a scary slow-moving fang-baring underwater centipede that is the first venomous crustacean to ever be discovered.

Also known as Godzillidae due to its monstrous appearance, little is known about these venomous crustaceans because they live deep inside underwater caverns and aquifers. What is known is that they’re blind, feature hardly any coloration, are classed as hermaphrodites, possess a pair of venom-secreting fangs and dozens of paddling legs, and are very, very, very creepy to look at.

Natasha Elder
By Natasha Elder

Natasha is a mother, a wife, a writer, and a serial cat owner. Though she is currently in mourning, her heart not ready for another feline family member just yet, she has always lived life with four paws beside her. She loves – you guessed it – cats, as well as creatures of the fluffy, scaly, and finned variety. Natasha longs to meet Sir David Attenborough one day and is passionate about responsible pet ownership