The coelacanth – a giant, mysterious fish that has survived from the time of the dinosaurs – can live for 100 years, a study found. These fish, which move slowly and grow to the size of a human, are nicknamed “living fossils” and also grow at a very slow pace.
Females do not reach sexual maturity until the late 50s, according to the study by French scientists, while male coelacanths reach sexual maturity between 40 and 69 years. And perhaps strangest of all, researchers believe that pregnancy in these fish lasts about five years.
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Coelacanths, which have existed for 400 million years, were thought to be extinct until they were found alive in 1938 off the coast of South Africa. Scientists have long believed that coelacanths lived for about 20 years.
But using a standard technique for dating commercial fish, French scientists calculated that they live for about a century, according to a study published in the journal Current Biology.
Coelacanths are so endangered that scientists can only study specimens already captured and dead.
In the past, scientists calculated the age of fish by counting large lines on a specific coelacanth scale. But French scientists found it lacked smaller lines that could only be seen using polarized light – the technique used to calculate the age of commercial fish.
Bruno Ernande, a marine evolutionary ecologist at the French marine research institute and co-author of the study, said polarized light revealed five smaller lines for each of the large ones. The researchers concluded that the smallest lines correlated better with the one-year-old coelacanth—and that it indicated that their oldest specimen was 84 years old.
Using the technique, the scientists studied two embryos and calculated that they were both five years old. So, Ernande said, they calculated that the pregnancy lasts at least five years in coelacanths.
Although coelacanths are not genetically related to other deep-sea creatures such as sharks and rays, they age slowly, Ernande said. Sharks can live for hundreds of years.
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