Its sense of hearing is extremely acute, allowing it to localize the low-frequency noises generated by other feeding animals, and, by extension, sources of food.

The newborn sharks spend their first months in relatively sheltered reef nurseries on the outer continental shelf, growing substantially before moving into the open ocean.

The large size and cutting teeth of the silky shark make it potentially dangerous, and it has behaved aggressively towards divers.

However, data suggest that silky shark numbers are declining around the world, which prompted the IUCN to reassess its conservation status to Vulnerable in 2017.

A scientific description of the silky shark was first published by the German biologists Johannes Müller and Jakob Henle under the name Carcharias (Prionodon) falciformis, in their 1839 Systematische Beschreibung der Plagiostomen.

[5][6] Because Müller and Henle's type specimen was a 53-cm-long female fetus from Cuba, adult silky sharks were historically not recognized as C. falciformis and were described as a separate species, Carcharhinus floridanus, by Henry Bigelow, William Schroeder, and Stewart Springer in 1943.

[10] Mine Dosay-Abkulut's 2008 ribosomal DNA analysis, which included the silky, blue, and bignose sharks, confirmed the closeness of those three species.

In the Atlantic Ocean, it is found from Massachusetts (USA) to Spain in the north, and from southern Brazil to northern Angola in the south, including the Gulf of Mexico and the Caribbean Sea.

[17] It occurs throughout the Indian Ocean, as far south as Mozambique in the west and Western Australia in the east, including the Red Sea and the Persian Gulf.

[3] Slim and streamlined, the silky shark has a fairly long, rounded snout with barely developed flaps of skin in front of the nostrils.

Each dermal denticle is diamond-shaped and bears horizontal ridges leading to posterior marginal teeth, which increase in number as the shark grows.

[7][8] The back is metallic golden-brown to dark gray and the belly is snowy white, which extends onto the flank as a faint lighter stripe.

[27] Compared to the other two species, it is less strictly pelagic with the greatest numbers found in offshore waters associated with land, where food is more readily obtained than farther out in the truly open ocean.

[8][22][32] Silky sharks within a group have been observed to "tilt", presenting their full lateral profile towards each other, as well as gape their jaws or puff out their gills.

On occasion, sharks have also been seen suddenly charging straight up, veering away just before reaching the surface and gliding back down to deeper water.

[28] When confronted, the silky shark may perform a threat display, in which it arches its back, drops its tail and pectoral fins, and elevates its head.

The shark then proceeds to swim in tight loops with a stiff, jerky motion, often turning broadside towards the perceived threat.

[34] Known parasites of this shark include the isopod Gnathia trimaculata,[35] the copepod Kroeyerina cortezensis,[36] and the tapeworms Dasyrhynchus variouncinatus and Phyllobothrium sp.

One account from the Red Sea describes 25 silky sharks following a large pod of bottlenose dolphins (Tursiops sp.

[30] Studies conducted off the Florida coast and the Bahamas have shown that silky sharks are highly sensitive to sound, in particular low-frequency (10–20 Hz), irregular pulses.

Silky sharks likely orient to these sounds because they are similar to the noise generated by feeding animals such as birds or dolphins, thus indicating promising sources of food.

[42] Silky sharks in most parts of the world are thought to reproduce year-round, whereas mating and birthing in the Gulf of Mexico take place in late spring or early summer (May to August).

[3] The pups are born in reef nursery areas on the outer continental shelf, where ample food supplies and protection from large pelagic sharks occur.

Even greater numbers are caught incidentally by tuna longline and purse seine fisheries throughout its range, particularly those using fish aggregating devices.

Nevertheless, mounting evidence indicates the silky shark has, in fact, declined substantially worldwide, a consequence of its modest reproductive rate which is unable to sustain such high levels of exploitation.

Regional assessments have found similar trends, estimating declines of some 90% in the central Pacific from the 1950s to the 1990s, 60% off Costa Rica from 1991 to 2000, 91% in the Gulf of Mexico from the 1950s to the 1990s, and 85% (for all large requiem sharks) in the northwestern Atlantic from 1986 to 2005.

However, Japanese fisheries in the Pacific and Indian Oceans have recorded no change in catch rate between the 1970s and the 1990s,[1] and the validity of the methodologies used to assess declines in the Gulf of Mexico and the northwestern Atlantic have come under much debate.

The silky shark is listed on Annex I, Highly Migratory Species, of the United Nations Convention on the Law of the Sea, though this has yet to result in any management schemes.

The species should benefit from bans on shark finning, which are being increasingly implemented by nations and supranational entities, including the United States, Australia, and the European Union.

[3] However, given the highly migratory nature of the silky shark and its association with tuna, no simple way is known to reduce bycatch without also affecting the economics of the fishery.