Search results
Results from the WOW.Com Content Network
The first shark-like chondrichthyans appeared in the oceans 400 million years ago, [1] developing into the crown group of sharks by the Early Jurassic. [2] Listed below are extant species of shark. Sharks are spread across 512 described and 23 undescribed species in eight orders. The families and genera within the orders are listed in ...
The use of sight probably varies with species and water conditions. The shark's field of vision can swap between monocular and stereoscopic at any time. [58] A micro-spectrophotometry study of 17 species of sharks found 10 had only rod photoreceptors and no cone cells in their retinas giving them good night vision while making them colorblind.
Sharks portal; Sharks constitute the superorder Selachimorpha in the subclass Elasmobranchii in the class Chondrichthyes.The Elasmobranchii also include rays and skates; the Chondrichthyes also include Chimaeras.
But many species of these aquatic apex predators are now in danger of dying out forever. Older than dinosaurs and trees, sharks have endured a lot throughout their 450 million years on Earth. They ...
The International Union for the Conservation of Nature reports 35% of all shark species are threatened with extinction. That number has grown nearly 50% in a decade’s time. That number has grown ...
Video above: Tail end of shark week celebrated at Shark Con. TAMPA, Fla. (WFLA) — Researchers have confirmed the existence of a new species of shark in South America.
Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million in total. Animals range in size from 8.5 millionths of a metre to 33.6 metres (110 ft) long and have complex interactions with each other and their environments, forming intricate food webs .
The great hammerhead shark is found in a variety of water depths such as shallow lagoons and coral reefs, and in deeper waters up to 984 feet. These sharks frequent coastal and tropical waters, as ...