The Rarest Crayfish Species on Earth

[00:00:01]Crayfish are known by many names, such as crawdads, crawfish, yabbies, and mudbugs.

[00:00:07]These incredible freshwater crustaceans come in a huge variety of colors, patterns, and lifestyles.

[00:00:13]All the crayfish species on Earth combined make for a total of around 500 species, and one in about every three of those species is endangered, meaning that there are over 150 crayfish threatened with extinction and many rare crayfish out there.

[00:00:28]When looking at crayfish as a whole, most of these species have relatively small ranges when compared to other aquatic species like fish and amphibians, which in turn contributes to so many of these species being considered rare or endangered.

[00:00:41]For this video, I wanted to highlight some of the rarest crayfish on Earth.

[00:00:45]Some of these species are considered rare because they are isolated to a single tiny range, when others used to have a large range, but are now endangered as a result of human cause.

[00:00:54]Some have really specialized habitats, and some are just simply hard to find.

[00:01:01]The Shasta crayfish is endemic to a small section of northern California, namely the Pit River basin in Shasta County.

[00:01:09]The Shasta crayfish occurs in cold spring-fed streams with volcanic rubble in the Hat Creek and Fall River drainages. This narrow range and competition with the invasive signal crayfish have made it extremely rare.

[00:01:21]Surveys estimate that only a few hundred wild individuals remain. Adult Shasta crayfish reach around 2 to 4 inches or 5 to 10 centimeters in total body length.

[00:01:31]They're typically dark brown with bright orange-red undersides, with some turning blue in color. [music] Shasta crayfish are long-lived for a crayfish with an estimated lifespan of around 10 to 15 years in the wild. This species has been listed as critically endangered, reflecting its tiny population and threats from invasive species and habitat [music] loss.

[00:01:52]The Allegheny Mountain mudbug was recently described in 2019, and it's only known to exist in a few high elevation seepages and springs in the Allegheny Mountains of West Virginia and Virginia.

[00:02:04]It is a primary burrowing crayfish associated with cool, saturated mountain forests and seepage wetlands.

[00:02:10]Individuals are relatively small, typically 2 to 3 in or 5 to 7 cm. The most notable feature of this crayfish is the magnificent blue color. Its conservation status is currently vulnerable due to its very limited range and habitat specificity with threats including wetland drainage and development. The species is a conservation priority in both the states of Virginia and West Virginia.

[00:02:33]On the other side of the planet is another rare, beautiful blue species, the Lamington Blue Crayfish, which is a large spiny crayfish endemic to the mountain forests of Australia in southeastern Queensland and adjacent northern New South Wales.

[00:02:48]This species lives in cool, high altitude rainforest streams and seepages. Adults are among the larger freshwater crayfish, typically 4 to 8 in or 10 to 20 cm. They have a bright blue, green, or reddish body color with occasional white or orange morphs existing. Lamington crayfish are long-lived and slow to mature with an estimated lifespan of 20 to 40 years.

[00:03:08]They are currently protected under Australian law due to habitat loss, climate change, and over collecting. The conservation status of this species is listed as vulnerable.

[00:03:19]The hairy marron is one of the largest crayfish species on Earth. And it was actually highlighted in my video of the largest crayfish species. This is a critically endangered crayfish found in the upper Margaret River in southwestern Western Australia. It inhabits clear, cool river pools with plenty of shelter in forested terrain. Hairy marron grows large as 40 cm or 16 in in total length and can weigh as much as 1 to 2 kg or 2 to 5 lb, making them significantly larger than any of the other crayfish we're going to talk about today.

[00:03:49]They're distinguished by the dense, hair-like structures on their bodies, coloration is generally black to dark brown. It is believed that less than a few hundred individuals remain, and likely almost all are found in just three different river pools. The species is currently listed as critically endangered largely due to hybridization and competition with the introduced smooth barren.

[00:04:11]Heading back to the North American continent, we have the Benton County cave crayfish. This cave-dwelling crayfish is restricted to three limestone caves. Bear Hollow Cave, Logan Cave, and Old Pendergraft Cave, all found in Benton County, Arkansas.

[00:04:26]The Benton County cave crayfish is eyeless and depigmented or pure white.

[00:04:30]It is quite small, only about an inch and a half or 4 cm. This crayfish occupies clear cave streams and pools, typically staying along pool edges and avoiding cave entrances.

[00:04:40]As a cave dweller, it grows and reproduces slowly.

[00:04:44]Astonishingly, it is believed that individuals may live up to 75 years.

[00:04:48]Today, very few are left in the caves with surveys estimating under 200 total still left in existence. The species is now listed as critically endangered with threats including groundwater pollution and an overall vulnerability as they are limited to the caves.

[00:05:04]The Hell Creek cave crayfish is another separate species of cave crayfish. This one is also known from just three caves and one spring in Stone and Marion counties in Arkansas.

[00:05:15]It is also eyeless and white, but reaches around 2 and 1/2 to 3 in or 6 to 8 cm. These crayfish live in deep cave pools and muddy stream areas far inside the cave.

[00:05:26]Little is known about its biology, but it also likely lives for decades. The Hell Creek cave crayfish is extremely rare and listed as critically endangered. Current conservation efforts focus on monitoring and protecting water quality in its few known locations.

[00:05:42]The Caney Mountain cave crayfish takes it a step further as this species is only found in a single cave in Ozark County, Missouri.

[00:05:51]Like most cave crayfish, it is blind and unpigmented and about 2 in long. This species has long slender claws with very long antennae. This is a fascinating burrowing cave species [music] living most of its life not only in the cave but underground in the cave. This species has only been observed exiting its burrow chimneys a handful of times.

[00:06:10][music] The Caney Mountain Cave Crayfish is one of the rarest crayfish in North America and is vulnerable to any disturbance.

[00:06:17]On the European continent, the white-clawed crayfish is a native European crayfish found throughout much of Western Europe. However, there are some distinct isolated populations found in the British Isles and while they share the same scientific name as the mainland populations, the British Isles populations is the one I'll be referring to in this segment. In the British Isles, it prefers clear well-oxygenated rivers and streams often on limestone or chalk where it hides under the rocks and roots. Adults are olive brown with pale undersides on the claws. They grow up to be around 4 in or 10 cm. Populations have crashed due to the introduced signal crayfish as well as a crayfish plague pathogen of which the white-clawed crayfish have little resistance to. They are now listed as an endangered species.

[00:07:02]The Guyandotte River Crayfish is only found in the upper Guyandotte River Basin of West Virginia in Wyoming County, namely Clear Fork and Pinnacle Creek.

[00:07:11]Adults are around 3 to 4 in or 7 to 10 cm in length. They are olive brown to greenish in body color with blue highlights on the claws. It inhabits fast clean mountain streams and individuals mature slowly living roughly around 5 to 10 years. The species is listed as endangered due to its very limited distribution in only two streams. Major threats are habitat loss and impact from logging, coal mining, and other development. Its current population is thought to only be surviving in very small fragmented groups.

[00:07:41]The burrowing bog crayfish is a rare species found in some bogs in southern Alabama and Mississippi.

[00:07:47]This crayfish is extremely elusive and very little is known about the species.

[00:07:51]It spends almost its whole life underground with small burrows of visible chimneys of mud at the surface.

[00:07:57]The burrowing bog crayfish is believed to emerge at night and feed on insects, worms, and even small frogs. Because of its very specialized habitat and small range, it is considered imperiled, but so little is actually known about it that its conservation status is considered data deficient.

[00:08:13]The Nashville crayfish is endemic to the Mill Creek watershed in the Nashville, Tennessee area.

[00:08:18]It tolerates a wide range of urban and sediment-laden streams, but its range is very small, making it quite rare. It is usually around 4 in or 10 cm in length with a rusty colored body and orange-tipped claws. It was first listed as endangered in 1986, though in recent decades they have made a bit of a comeback where habitat restoration occurred, with more populations of the species beginning to develop.

[00:08:41]As far as rare crayfish species go, this video was only the tip of the iceberg.

[00:08:46]If you'd like to learn more about crayfish and other aquatic species, please consider subscribing to my channel and checking out my other videos. Thank you so much for watching and I hope to see you on the next one.