The World Long-Lived Crayfish
I read an article “400 Year Old Clam Found” a little ago. According to the article, a team of scientists from Bangor University’s school of Ocean Science dredged up the clam form the seabed in the cold waters off the North coast of Iceland. The age of the clam, called quahog clam, Artica islandica, has been assessed between 405 and 410 years, which replaced the existing record for the longest-lived animal in the Guiness Book of Records.
A quahog clam, Artica isladica, only grows in summer when the water is warmer and the plankton it eats is plentiful but stops growing in winter in the extremely cold water, therefore, has annual growth lines in its shell. The Bangor scientists studied the age of clams using the annual growth lines in much the same way as dendrochronologists study the age of trees using tree-rings.
The discovered quahog clam is 8.7 cm in length and 52 g in weight. I thought the clam is unexpectedly small compared to the great age.
The Bangor scientist team commented that when this animal was a juvenile, King James I replaced Queen Elizabeth I as English monarch, Shakespeare was writing his greatest plays Hamlet, Othello, King Lear and Macbeth and Giordano Bruno was burnt at the stake for espousing the view that the Sun rather the Earth was center of the universe.
The clam was alive when it was brought to the surface but it is pity that by peeling off the flesh from the shell to count annual growth lines the clam’s great lifetime ended. A researcher commented that doing nothing - the quiet life of a clam could explain its longevity. But I thought “it's you that have broken the quiet life of the clam !”
Every animal has its inherent longevity. Among mammals, mouse 4 years, rabbit 9 years, dog 15years, cat 15years, horse 40 years, elephant 70 years; among birds, chicken 15 years, sparrow 20 years, pigeon 30 years, eagle 40 years; among reptiles, snake 20 years, alligator 60 years; among amphibians, green frog 10 years, giant salamander 60 years; among fish, carp 50 years, cat fish 60 years; among insets, working bee 1 year, queen bee 5 years, cicada 7 years.
There is a saying “the crane is a-thousand-year and the tortoise is ten-thousand-year.” It’s exaggerating but it is true that crane and tortoise are long-lived animals. The Galapagos Land Tortoise is estimated to live to 200 years and Associated Press reported in March last year that the Aldabra Tortoise which died in a Calcutta zoo after 130-year life in the zoo was estimated 250 years old.
The crane lives for 70 to 80 years.
As for the longevity of the crayfish, if you keep a Procambarus clarkii in your tank for 3 years, it could be said long-lived. I hardly heard that it lived in a tank for more than five years. In nature Procambarus clarkii usually lives 5-7 years. Isn’t it short ?
In the U.S.A, however, there are crayfish whose longevity is 175 years. Its name is Cave Crayfish (Orconectes australis). This crayfish is eyeless because it has lived in a thoroughly dark cave, but use long antenna instead. Without light, the crayfish is white, almost transparent. It is 5-10 cm long, almost the same as Procambarus clarkii.
Troglobites - the technical name for millipedes, spiders, salamanders, fish, and shrimps living in the dark dead-end caves and evolving in isolated ecosystem. In the genuine darkness, desperate starvation, low oxygen and poison gases, they are born, eat, mate and overcome the severe circumstances from generation to generation. Cave Crayfish (Orconectes australis) is one of those creatures.
To survive stagnant, low-oxygen air and months without food, many troglobites have super-slow metabolisms. And because they live slow, they live long. Orconectes australis of the caves in the U.S.A. may reproduce at 100 years and live to 175. What a long-lived creature it is compared to Procambarus clarkii which reproduces at 1 year and lives for 5 to 7 years !
The University of Alabama started the research project that involves the capturing, measuring, tagging, releasing and, subsequent recapturing of hundreds of Cave Crayfish within 10 Alabama caves over 3-year period. It is designed to reveal more about the crayfish’s population size, individual growth rates and longevity.
The crayfish that is completing its 175-year life was born when it was still Edo era in Japan. It was 20-year prior to the year when Commodore Perry’s Black Ships brought Japan into the turmoil. Hokusai Katsushika, who is the renowned woodblock artist in Bunka-Bunsei era had completed Fugaku (Mt. Fuji) 36 Views and was ready to start Fugaku 100 Views Series. Even Isami Kondou who would be the director general of Shinsengumi later was in his mother’s womb at that time.
It’s really surprising that the old crayfish born so long ago has been still alive!
Anyway, the fact that, either cave crayfish or giant tortoise, the animal which lives super-slow lives long gives some intuition to human being, doesn't it?
