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Most sharks have eight fins: a pair of pectoral fins, a pair of pelvic fins, two dorsal fins, an anal fin, and a caudal fin. Pectoral fins are stiff, which enables downward movement, lift, and guidance. The members of the order Hexanchiformes have only a single dorsal fin. The anal fin is absent in the orders Squaliformes, Squatiniformes, and ...
Dorsal fin of a shark. A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom.Many species of animals possessing dorsal fins are not particularly closely related to each other, though through convergent evolution they have independently evolved external superficial fish-like body plans adapted to their marine environments ...
The first dorsal fin is positioned closer to the pelvic than the pectoral fins. The second dorsal fin, nearly equal to the first in size, is located over or slightly forward of the anal fin. No ridge is seen between the dorsal fins. The pectoral fins are long and broad, originating below the space between the third and fourth gill slits.
Vision is an important sensory system for most species of fish. Fish eyes are similar to those of terrestrial vertebrates like birds and mammals, but have a more spherical lens. Their retinas generally have both rod cells and cone cells (for scotopic and photopic vision), and most species have colour vision.
The longfin mako is a pelagic species found in moderately deep water, having been reported to a depth of 220 m (720 ft). Growing to a maximum length of 4.3 m (14 ft), the slimmer build and long, broad pectoral fins of this shark suggest that it is a slower and less active swimmer than the shortfin mako. Longfin mako sharks are predators that ...
Carcharhiniformes / kɑːrkəˈraɪnɪfɔːrmiːz /, the ground sharks, are the largest order of sharks, with over 270 species. They include a number of common types, such as catsharks, swellsharks, and requiem sharks. Members of this order are characterized by the presence of a nictitating membrane over the eye, two dorsal fins, an anal fin ...
The second dorsal fin is located midway between the first dorsal and the caudal fin. The broad and triangular pectoral fins have a deep indentation where their leading margins meet the head. The pelvic fins are much smaller than the pectoral fins, and the anal fin is absent. The tail is much longer than the body and ends in a large, crescent ...
The first dorsal fin is small and somewhat sickle-shaped, with a pointed apex and a short, free, rear tip; its origin lies over the free rear tips of the pectoral fins. The second dorsal fin is relatively large, though still less than half the height of the first. No ridge is seen between the dorsal fins. The pectoral fins are short and tapered ...