Why do coelacanths' fins look like legs?
Overview of the coelacanth.
Contunico © ZDF Studios GmbH, Mainz
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Transcript
The sea - it's abstract, mysterious quality is multiplied the deeper down you go. There is life at these depths that has survived for millions of years, true living fossils, such as the coelacanth. The first indications of the existence of this unusual fish with fins resembling legs were found in sedimentary deposits stemming from the Palaeozoic Era, stretching back over 400 million years ago.
Coelacanths spend their days in lava tubes, caves located as deep as 200 meters below the ocean's surface. But even so far down, they never touch bottom. Their physical structure is perfectly adapted for floating above the sea bed. This is despite the fact that they move their fins in the same rhythmic cycle as tetrapods. Scientists assume that these living fossils once used their muscular fins for locomotion, perhaps even on land.
Coelacanths can grow to lengths of up to two meters and weigh as much as 100 kilograms. These fish only leave their caves at night when they hunt for food, diving then to depths of up to 700 meters. Coelacanths swim in a particular drifting manner that uses even the slightest water current for locomotion. Their large pectoral and ventral fins are used to maintain their balance. Their primary habitat is the waters of the Comoros Islands. Specimens that researchers have found in other places were simply ocean travellers.
Coelacanths spend their days in lava tubes, caves located as deep as 200 meters below the ocean's surface. But even so far down, they never touch bottom. Their physical structure is perfectly adapted for floating above the sea bed. This is despite the fact that they move their fins in the same rhythmic cycle as tetrapods. Scientists assume that these living fossils once used their muscular fins for locomotion, perhaps even on land.
Coelacanths can grow to lengths of up to two meters and weigh as much as 100 kilograms. These fish only leave their caves at night when they hunt for food, diving then to depths of up to 700 meters. Coelacanths swim in a particular drifting manner that uses even the slightest water current for locomotion. Their large pectoral and ventral fins are used to maintain their balance. Their primary habitat is the waters of the Comoros Islands. Specimens that researchers have found in other places were simply ocean travellers.