The Yeti Crab (Kiwa hirsuta), a hairy crab with no eyes, was first discovered along a hydrothermal vent near the Pacific-Antarctic ridge. Not only is it a new species but it also belongs to a new family of crustaceans, Kiwa, named after the legendary Polynesian goddess of shellfish. The name hirsuta is derived from the Latin word for “hairy.” We will learn more about this species below.
Appearance
The Yeti Crab stands out for its hairy pincers and body. It has a lobster-like appearance replete with a hard shell, lengthy appendages, and large claws. It also resembles the mythological snowman Yeti, after whom it was nicknamed.
It has a small, all-white body typically six inches long with lengthy claws lined with yellowish hair-like spines that allow it to gather bacteria or find mates. The Yeti’s bristles are also known as setae and are lined with physical and chemical sensors.
Some individuals of this species can have hairy chests, either in addition to or instead of hairy claws. Additionally, it is assumed their eyes are shrunken and they may be partly or fully blind.
Diet
The Yeti Crab performs a fascinating dance, waving its arms in the water around deep-sea vents to cultivate its main source of food: bacteria. The movement brings fresh oxygen and nutrients to the bacterial colonies on the crab’s arms.
These bacteria are chemoautotrophs and use chemicals from the vents to produce their own food, similar to how plants use sunlight. Scientists believe the Yeti Crab grazes on these bacteria with its comb-like mouthparts, essentially farming its dinner.
Yeti Crabs have also been reported eating mussels and fighting over shrimp, implying they are either carnivorous or omnivorous.
Habitat
The Yeti Crab was discovered amid hydrothermal vents of the Pacific-Antarctic ridge, about 1,000 miles south of Easter Island. These vents are essentially cracks in the ocean floor and Earth’s crust spewing superheated water at depths of roughly 7,200 feet (2,200 meters).
The habitable zone for Yeti Crabs is a delicate balance. The surrounding deep-sea is lethally cold, forcing them to stay near the warm waters of the hydrothermal vents. This limited habitat, just a few cubic meters in volume, is where they’ve adapted to thrive. The hydrothermal vents provide many other creatures, such as tube worms, shrimp, and bacteria with nutrients and minerals important for their survival.
Yeti Crabs huddle together in dense clusters, clinging to each other and the seafloor for stability. They form living towers to stay within the life-giving warmth of the vents.
Reproduction
Given its recent discovery and challenging location, little information exists about Yeti Crab reproduction. However, researchers observed egg-carrying female Yeti Crabs venturing away from the warmth of the vents.
Scientists believe that cooler temperatures are crucial for proper egg development. Additionally, the intense heat and sulfur-rich environment near the vents would likely harm the delicate eggs.
Unfortunately, these female Yeti Crabs don’t feed during the brooding period and essentially starve themselves. After they release their larvae into the cooler waters, they are likely too weak to fight their way back into the crowded haven around the vents and they die.
Species
There are three discovered species of the Kiwaidae family:
Kiwa puravida
This species was discovered in 2006 in cold seeps on the Costa Rican seafloor. They share anatomical similarities with the Kiwa hirsuta and also feed on symbiotic bacteria. The species name, which means “pure life” in English, is derived from a Costa Rican proverb. Kiwa puravida may be found in methane seeps at depths of 1,007 meters.
Kiwa tyleri
This species was identified in Antarctica in 2010 during an expedition to investigate the hydrothermal vents on the East Scotia Ridge in the Antarctic Ocean.
Because they have small chelae and most of their setae are focused on the ventral side, the morphological traits of this species differ from those of the Kiwa puravida and Kiwa hirsuta. Their nickname “Hoff crabs” is inspired by the actor David Hasselhoff’s hairy chest.
Kiwa araonae
This species was identified in 2013 near the hydrothermal vents on the Australian-Antarctic Ridge in the Southern Ocean. This species is distinguished physically by a virtually flat branchial area, a short rostrum, and thin pincers. They are not as hairy as their counterparts.
Threats
Not much is known about the conservation status of the Yeti Crab. These crabs do not appear to have many natural predators, but they are targeted by deep-sea octopuses and fish.
5 Facts About Yeti Crab
- The Yeti Crab is a distant relative of the hermit crab.
- Yeti Crab was first discovered in 2005 by a group of scientists.
- The Yeti Crab lives around deep-sea hydrothermal vents with over 700 crabs per square meter.
- According to genetic evidence, the Yeti Crab family developed 30 to 40 million years ago when its ancestors first inhabited hydrothermal vents.
- The exact figure for the lifespan of the crab is still unknown, but it is assumed that the Yeti Crab can live for 20 years.
FAQs
Who discovered the Yeti Crab?
Marine researchers from Monterey Bay Aquarium used the research submersible Alvin to examine hydrothermal vents along the Pacific-Antarctic ridge south of Easter Island and discovered this crab in March 2005.
How do Yeti Crabs see?
Since Yeti Crabs lack eyes, scientists believe their hairy bristles, called “setae”, might act as super-sensitive touch receptors. These tiny hairs act like chemical and physical sensors, helping the crabs navigate the dark depths to find food or even potential mates.
How do Yeti Crabs breathe?
A key adaptation for Yeti Crabs is their supersized gill chambers. These enlarged chambers allow them to breathe more efficiently in the oxygen-depleted environment of the deep sea. Scientists can even identify these enlarged chambers by examining the special groove patterns on the Yeti Crab’s shell.
How did Yeti Crabs evolve?
Genetic clues suggest Yeti Crabs may have originated in a less harsh environment than the hydrothermal vents they call home today. They likely branched off from their ancestors, venturing into these superheated zones later in their evolutionary journey. Their common ancestor was a pioneer that lived about 30 to 40 million years ago.
Can Yeti Crabs swim?
Yes, they can. Yeti Crabs propel themselves through the water using a technique called drag-powered swimming. This involves a repetitive motion where they push water backward with a powerful stroke, then bring their limbs forward in a recovery stroke for the next push.
