Researchers in South make new findings about 'hairy Hoff crab'
Scientists say its the first species in its family to have different claw characteristics between sexes
Researchers in the South have discovered more details which differentiate between a hairy crustacean dubbed the 'Hoff crab'.
The creature was given its name by University of Portsmouth professor Dr Nicolai Roterman when it was discovered in 2010 because of its hairy belly - reminiscent of the chest of Baywatch actor David Hasselhoff.
Researchers there and at the University of Southampton have now found the species is the first in its family to show different claw characteristics between sexes.
Males in the species have oversized claws compared to females of similar sizes.
The study, published in PLOS One, says this marked difference likely suggests the larger claws are used for males to compete with each other for access to a mate, but it may also reflect females focusing energy resources on reproduction.
The creature, whose official name is Kiwa tyleri, is a type of deep-sea crustacean which lives in vast communities around hot vents on the seafloor in Antarctica. Its many hairs host bacteria that the animal harvests to sustain itself.
The Hoff Crab is part of the Kiwaidae family, first discovered in 2005, which is made up of animals commonly referred to as "yeti crabs”, after the legendary yeti because of their bristly appearance.
Teams examined 135 specimens from the East Scotia Ridge in the Scotia Sea off Canada.
Dr Roterman, a deep-sea ecologist from the University of Portsmouth’s School of the Environment and Life Sciences, said:
"This is the first study to show claw sexual dimorphism in yeti crabs – which live exclusively in harsh deep-sea environments like hydrothermal vents and methane seeps.
"Knowing that there’s a difference in size between the male and female claws helps us understand the behaviour and ecology of the yeti crab family - which we know little about because they are a fairly recent discovery, and their home is very difficult to reach.
"Physical differences between males and females is a common feature of decapod crustaceans which live in shallow water, and usually it's because the male is forced to guard the mate, or females have to divert their growth energy for reproduction.”
Dr Roterman added that crabs are able to survive by crowding around hot hydrothermal vents in the waters around the Antarctic, which are normally cold enough to make living incredibly difficult for crab-like animals.
The vents are made up of volcanic rock systems that draw water through cracks in the seafloor, super-heat it, load it with dissolved metals and other chemicals, and then eject it back into the ocean.
The crab feeds by "farming" bacteria - known as chemosynthetic microbes - that are sustained by chemicals in the 380 degree water coming out of the hydrothermal vent chimneys.
By climbing the sides of the chimney-like structures, the crabs are able to maximise bacteria growth, but risk cooking themselves or suffocating if they get too close to the super heated, de-oxygenated water coming out of the chimney.
Dr Roterman explained the importance in studying these deep sea creatures:
“Understanding the physiology, behaviour, ecology and evolution of animals adapted to the most extreme conditions give us insights into what evolution is capable of, and therefore how life is likely to adapt to a warming planet and other natural and human-induced ecological stressors.”