Salmon shark in the context of "White shark"

The great white shark (Carcharodon carcharias), also known as the white shark, white pointer, or simply great white, is the largest living macropredatory shark and fish. It is a mackerel shark and closely related to the mako sharks, the porbeagle and the salmon shark. It is a robustly built species with a grayish upper-side and a white underside. Females average 4.6 to 4.9 m (15 to 16 ft) and weigh 1,000–1,900 kg (2,200–4,200 lb) while males average 3.4 to 4.0 m (11 to 13 ft) and weigh 680–1,000 kg (1,500–2,200 lb). They are estimated to reach a length close to 6.1 m (20 ft) and a weight of over 2,494.9 kg (5,500 lb). The shark has approximately 300 triangular, serrated teeth that are continuously replaced. Its massive, fatty liver can reach over a quarter of its body weight and provides buoyancy and energy. White sharks are unusual among fish in that they are warm-blooded, an adaptation that allows them to remain active in colder waters.

White sharks inhabit tropical and temperate ocean waters around the world and can be found both along the coast and further out to sea. Populations are most concentrated at the Pacific and Atlantic sides of North America and in the waters of southern Africa and Oceania. They are a highly migratory species, traveling between the coast and open ocean and even between continents. The great white shark preys on marine mammals such as pinnipeds and dolphins, as well as fish, including other sharks, and cephalopods. It is also a prolific scavenger of whale carcasses. Though an apex predator, the species itself is sometimes preyed on by orcas. White sharks are generally solitary but gather in aggregations, particularly at feeding sites. They may communicate and establish dominance hierarchies with body language. Reproduction in the species is less understood, but it is known to be ovoviviparous; with pups hatching from eggs within the female, who gives live birth after 12 months. Juvenile white sharks typically inhabit shallower water and cannot eat marine mammals until they reach around 3 m (9.8 ft).

The porbeagle or porbeagle shark (Lamna nasus) is a species of mackerel shark in the family Lamnidae, distributed widely in the cold and temperate marine waters of the North Atlantic and Southern Hemisphere. In the North Pacific, its ecological equivalent is the closely related salmon shark (L. ditropis). It typically reaches 2.5 m (8.2 ft) in length and a weight of 135 kg (298 lb); North Atlantic sharks grow larger than Southern Hemisphere sharks and differ in coloration and aspects of life history. Gray above and white below, the porbeagle has a very stout midsection that tapers towards the long, pointed snout and the narrow base of the tail. It has large pectoral and first dorsal fins, tiny pelvic, second dorsal, and anal fins, and a crescent-shaped caudal fin. The most distinctive features of this species are its three-cusped teeth, the white blotch at the aft base of its first dorsal fin, and the two pairs of lateral keels on its tail.

The porbeagle is an opportunistic hunter that preys mainly on bony fishes and cephalopods throughout the water column, including the bottom. Most commonly found over food-rich banks on the outer continental shelf, it makes occasional forays both close to shore and into the open ocean to a depth of 1,360 m (4,460 ft). It also conducts long-distance seasonal migrations, generally shifting between shallower and deeper water. The porbeagle is fast and highly active, with physiological adaptations that enable it to maintain a higher body temperature than the surrounding water. It can be solitary or gregarious, and has been known to perform seemingly playful behavior. This shark is aplacental viviparous with oophagy, developing embryos being retained within the mother's uterus and subsisting on non-viable eggs. Females typically bear four pups every year.