The largest and most widely distributed member of its genus, the milk shark typically measures 1.1 m (3.6 ft) long, and can be found in coastal tropical waters throughout the eastern Atlantic and the Indo-Pacific regions.

Occurring from the surface to a depth of 200 m (660 ft), this species is common near beaches and in estuaries, and has been recorded swimming up rivers in Cambodia.

The milk shark has a slender body with a long, pointed snout and large eyes, and is a nondescript gray above and white below.

Large numbers of milk sharks are caught by artisanal and commercial fisheries in many countries for meat, fins, and fishmeal.

The German naturalist Eduard Rüppell published the first scientific description of the milk shark, as Carcharias acutus (the specific epithet means "sharp" in Latin), in his 1837 Fische des Rothen Meeres (Fishes of the Red Sea).

It has since been listed under several different genera, including Carcharhinus and Scoliodon, before finally being placed in the genus Rhizoprionodon via synonymization with the type species, R.

[2][3] As Rüppell did not mention a type specimen, in 1960, Wolfgang Klausewitz designated a 44 cm (17 in)-long male caught off Jeddah, Saudi Arabia as the lectotype for this species.

[4] A 1992 phylogenetic analysis by Gavin Naylor, based on allozymes, found that the milk shark is the most basal of the four Rhizoprionodon species examined.

Since 1985, there have been four occurrences, temporally and spatially distinct, of the milk shark in the central Mediterranean Sea, with a likely entry via the Strait of Gibraltar.

In the Pacific Ocean, this species occurs from China and southern Japan, through the Philippines and Indonesia, to New Guinea and northern Australia.

[6] Occurring close to shore from the surf zone to a depth of 200 m (660 ft), the milk shark favors turbid water off sandy beaches and occasionally enters estuaries.

[10] Although some sources state this species avoids low salinities,[2][3] it has been reported several times from fresh water in Cambodia, as far upstream as the Tonlé Sap.

[14] The milk shark has a slender build with a long, pointed snout, large, round eyes with nictitating membranes (protective third eyelids), and no spiracles.

[12] Parturition also occurs continuously in Australian waters; in the Herald Bight of Shark Bay, the number of newborns peaks in April and again in July.

During the second phase, which also lasts for two months to an embryonic length of 81–104 mm (3.2–4.1 in), the external gill filaments develop and the yolk sac begins to be resorbed, the embryo ingesting histotroph (a nutritious substance secreted by the mother) in the meantime.

In the third phase, lasting six to eight months, the depleted yolk sac is converted into a placental connection through which the fetus receives nourishment until birth.

[20][21][22] In Herald Bight, large groups of small milk sharks can be found in shallow tidal pools, as well as in seagrass beds where they are sheltered from predators by the dense, tall vegetation.

Off northern Australia, it ranks among the most common sharks caught in trawls, and comprises 2% and 6% of the annual gillnet and longline catches, respectively.

[1] In the 1980s and early 1990s, stock assessments of the milk shark off India's Veraval coast concluded catches by gillnet and trawl fisheries were below the maximum sustainable level.