Photo: An endangered coelacanth fish

Thought to have been long extinct, scientists discovered these "living fossils" in 1938.

Photograph by Gerard Lacz/Animals Animals—Earth Scenes

Map

Map: Coelacanth range

Coelacanth Range

Fast Facts

Type:
Fish
Diet:
Carnivore
Average life span in the wild:
Up to 60 years
Size:
6.5 ft (2 m)
Weight:
198 lbs (90 kg)
Group name:
School
Protection status:
Endangered
Did you know?
A coelacanth's miniscule brain occupies only 1.5 percent of its cranial cavity; the rest is filled with fat.
Size relative to a 6-ft (2-m) man:
Illustration: Coelacanth compared with adult man

The primitive-looking coelacanth (pronounced SEEL-uh-kanth) was thought to have gone efxtinct with the dinosaurs 65 million years ago. But its discovery in 1938 by a South African museum curator on a local fishing trawler fascinated the world and ignited a debate about how this bizarre lobe-finned fish fits into the evolution of land animals.

There are only two known species of coelacanths: one that lives near the Comoros Islands off the east coast of Africa, and one found in the waters off Sulawesi, Indonesia. Many scientists believe that the unique characteristics of the coelacanth represent an early step in the evolution of fish to terrestrial four-legged animals like amphibians.

The most striking feature of this "living fossil" is its paired lobe fins that extend away from its body like legs and move in an alternating pattern, like a trotting horse. Other unique characteristics include a hinged joint in the skull which allows the fish to widen its mouth for large prey; an oil-filled tube, called a notochord, which serves as a backbone; thick scales common only to extinct fish; and an electrosensory rostral organ in its snout likely used to detect prey.

Coelacanths are elusive, deep-sea creatures, living in depths up to 2,300 feet (700 meters) below the surface. They can be huge, reaching 6.5 feet (2 meters) or more and weighing 198 pounds (90 kilograms). Scientists estimate they can live up to 60 years or more.

Their population numbers are, predictably, not well known, but studies in the Comoros suggest only about 1,000 remain there. They are considered an endangered species.

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