Species Spotlight #2: “Dancing” Yeti Crab

If you haven’t seen the prequel for the upcoming nature documentary series BBC Blue Planet 2, where have you been? The trailer features a mixture of stunning clips from the new series, narrated by zoology icon David Attenborough and overlaid with an epic soundtrack blending vocals from rock band Radiohead and music from Hans Zimmer. Just from the trailer, we can see how far the technology available for filming creatures underwater has come since the last big underwater series, The Blue Planet (2001). If you’re a nature documentary nerd like me (and even if you’re not), it is super exciting. To celebrate the new series, this week’s Species Spotlight features a species that starred in the Blue Planet 2 prequel, the “newly discovered dancing yeti crab“, in the words of Sir David.

Drawing of "Yeti" crab (Kiwa hirsuta) discovered south of Easter Island
Yeti crab illustration by Karen Jacobsen

Discovered in 2005 by scientists conducting a deep-sea expedition onboard the submarine Alvin, this peculiar crustacean spends its time blindly ambling along the hydrothermal vents that line the Pacific-Antarctic ridge, near Easter Island (Macpherson et al., 2005). Its name means “Hairy guardian of the sea“, so called for its arms covered in colonies of filamentous bacteria.

Not much is currently known about the ecology of the yeti crab, or indeed why they wave their hairy arms about as if they were dancing. Perhaps the crabs are farming their arm bacteria to use as a food source, or to detoxify poisonous minerals emitted by the vents in their habitat. Or, given that the crabs are thought to be blind, the filaments on their arms could be used for sensory navigation through the darkness of their habitat. Maybe they are simply waving to submarine passers-by. Without a doubt, the new series of Blue Planet will shed some light on the many mysteries of the yeti crab.

yeti crab
“Dancing Yeti Crabs” from BBC Blue Planet 2 (2017)

Binomial Name: Kiwa hirsuta

Common Name: Yeti Crab

Taxonomy: Animalia – Arthropoda – Crustacea – Malacostraca – Decapoda – Anomura – Kiwaidae – Kiwa – K. hirsuta

Size: ~15cm long

Lifespan: unknown

Reproduction: unknown

Beauty:  Despite lack of pigmentation, yeti crabs manage to look adorable. With their arms all covered in silky blond bacteria, they look almost fluffy. Still, this is only the second Species Spotlight post, and we don’t want to get carried away here, so I’ve given them a modest score.

Animal Beauty Pageant Score: 20/100 

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Yeti crab claw (2005 Ifremer / A. Fifis)

Deadliness: Although these crustaceans do have pincers, the crabs themselves are just 15cm (5.9 inches) long. Not quite so deadly. 

Deadliness Score: 10/100

Potential for World Domination: As far as we know, yeti crabs are confined to living along the hydrothermal vents of the Pacific-Antarctic ridge, at a depth of around 2,200 metres. It seems like these crabs are just down there doing their thing and occasionally, you know, dancing. Like no-one is watching. (See below for video evidence).

World Domination Score: 10/100

 

 

Relationship with Humans: Perhaps luckily for the yeti crabs, human visits to their deep sea habitat are rare. However, hydrothermal vents and the surrounding seabed areas are currently under threat from deep-sea mining for minerals and metals such as silver, copper, manganese and zinc. Currently, it is not known how mining may affect deep-sea ecosystems, but care ought to be taken to preserve these fantastic communities of species that live on the vents, such as the yeti crab.

“Getting Along With Homo sapiens” Score: 40/100

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Alvin, the submarine used for deep-sea expeditions, in 1978 (NOAA)

Fame Factor: As they have only recently been discovered, yeti crabs have been out of the limelight. However, once the upcoming episode of BBC Blue Planet 2 where yeti crabs strut their stuff airs, you bet that these funky crabs will be the talk of the town. I think it’s only fair to give these cool crustaceans a high score in this category, in anticipation of their future fame.   

Fame Factor Score: (soon to be) 70/100 

Total Species Spotlight Score: 150/500

The first episode of Blue Planet 2, One Ocean, officially airs on BBC One this Sunday 29th October at 20:00. I. CAN’T. WAIT.

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Check out more about the upcoming series Blue Planet 2 on the BBC Earth Website

Find out more about Deep Sea Mining

E. Macpherson, Jones, W., and Segonzac, M. (2005). A new squat lobster family of Galatheoidea (Crustacea, Decapoda, Anomura) from the hydrothermal vents of the Pacific-Antarctic Ridge. Zoosystema, 27:4.

Monterey Bay Aquarium Research Institute “Discovery of the Yeti Crab” (2006) http://www.mbari.org/discovery-of-yeti-crab/

Feature Image Credit: Ifremer / A. Fifis (2005)

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Species Spotlight #1: Great Tit

This blog is all about showcasing the wonderful diversity of animal species, by shining the spotlight on one particular animal every week and ranking them in some kind of knock-off zoological Top Trumps fashion. To kick off the blog and Species SpOtlight post series, it makes sense to start with a feature on my PhD study species. So, here I’d like to introduce you all to the great tit, the largest, and second feistiest (the blue tit takes the crown here) tit species in the United Kingdom!

Binomial Name: Parus major

Common Name: Great Tit

Taxonomy: Animalia – Chordata – Aves – Passeriformes – Paridae – Parus – P. major

Size: Weight 16-20 g, Length 12.5-14.0 cm

Lifespan: 2-3 years

Reproduction: 5-11 eggs per clutch, 1-2 clutches per year. Female incubates the eggs, and then both parents usually work together to rear chicks from hatching to fledging!

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Beauty:  With a glossy black head, bright white cheeks and sunshine yellow belly feathers, the great tit is one of the most handsome passerines around. Am I biased? Possibly. Great tits are truly stunning birds, and therefore IMO they deserve a fairly high score in this category.

Animal Beauty Pageant Score: 80/100 

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One ~*~super glamorous~*~ great tit. [Credit: Stanislav Harvancik]
Deadliness: Great tits mostly chow down on insects, nuts and seeds. However, there have been some recorded cases of tits scavenging on carcasses left by predators, while other food is scarce. These seemingly innocent birds have even been documented killing small bats and then eating their brains (Estók et al., 2010). Great tits are also often aggressive towards other passerines, forcefully fighting off other smaller bird species at feeders. For their size, great tits are powerful and can do quite some damage using their beaks – if you happen to be a small bird or a bat, that is. 

Deadliness Score: 60/100

Great tits scavenging on a wolf kill [Credit: Nadleśnictwo Baligród, Poland]

Potential for World Domination: Great tits are currently listed on the IUCN database as Least Concern, with a rough estimate of the world population standing at 433,300,000-703,300,000 mature individuals. The species is widespread in Europe and its range is large, stretching throughout the Middle East, North Africa and Central Asia. Great tits can be found in a range of habitats from urban parks to oak woodlands and scrubland, making it a fairly versatile species. 

World Domination Score: 30/100

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Map of current Great tit distributions [Wikipedia]
Relationship with Humans: This species has adapted fairly well to life in urban environments and is commonly sighted in cities like Sheffield, UK, where the great tit population has been estimated to be upwards of 17,000 individuals (Fuller et al., 2009). Still, reproductive success for great tits raising their young in the city is often lower than those living in forest environments. There is still much to be discovered about the impacts of urban factors such as light pollution, noise, environmental toxins and habitat fragmentation on the health of great tits that live in and share our cities.

“Getting Along With Homo sapiens” Score: 75/100

 

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A wee Glaswegian great tit

Fame Factor: Great tits are important in the scientific field of ornithology (bird studies). Due to their ubiquitousness and willingness to nest in nest boxes, great tits make ideal models for ecological field studies. In fact, from 1969 to 2002, an estimated 1,349 scientific articles were published relating to great tits (Kvist et al., 2003)!  Moreover, in the UK the great tit is one of the most common garden birds sighted, so as far as garden birds go, great tits are pretty darn famous.

Fame Factor Score: 90/100

Total Species Spotlight Score: 335/500

 

Estók, P., Zsebők, S. & Siemers, B. M. 2010. Great tits search for, capture, kill and eat hibernating bats. Biology Letters, (6), 59-62.

Fuller RA, Tratalos J, Gaston KJ (2009). “How many birds are there in a city of half a million people?”. Diversity and Distributions15 (2): 328–337. 

Kvist, Laura; Martens, Jochen; Higuchi, Hiroyoshi; Nazarenko, Alexander A; Valchuk, Olga P.; Orell, Markku (2003). “Evolution and genetic structure of the great tit (Parus major) complex”Proceedings of the Royal Society B270 (1523): 1447–1454.