Night Shark

• Maximum length2.8 m (9.2 ft); most adults 1.8–2.2 m
• WeightUp to about 76 kg (169 lb) on record
• LifespanAt least 17 years aged; 28–30 years estimated
• Depth rangeUsually 50–600 m (165–1,970 ft); recorded to about 2,000 m
• DietSmall schooling fish, squid, shrimp
• IUCN statusEndangered (assessed 2019)

How to tell a night shark from other requiem sharks

Pull a night shark out of the water and the first thing you notice is the eye. It is large, almost perfectly round, and in a living animal the iris glows a vivid green; the colour fades within hours of death, which is why old museum specimens give no hint of it. Combine that eye with a snout that is long, narrow and pointed, clearly longer than the mouth is wide, and you already have the species.

The rest of the body confirms it. The night shark is slender for a requiem shark, with a low first dorsal fin that starts behind the pectoral fins, a very small second dorsal fin set above the anal fin, and a low ridge of skin running between the two dorsals. The pectoral fins are long, narrow and slightly curved. Colour is grey-blue to grey-brown above, fading to white below, and most individuals carry a sprinkling of tiny black dots along the back and flanks, though these can be faint. There are no black or white fin tips to help you, which separates it at once from the silky shark and the spinner shark that share its waters.

The teeth are small and asymmetric: around 15 rows on each side of the upper jaw, with oblique, slightly serrated cusps, and a similar number of narrow, smooth-edged, erect teeth below. The bignose shark is the closest look-alike, but it has a blunter snout with large nasal flaps and a much taller first dorsal fin.

How big does a night shark get?

The largest night shark on record measured about 2.8 m (9.2 ft) and weighed a little over 76 kg (169 lb), an angling record from the western Atlantic. That is the ceiling, not the norm. Most adults caught on longlines fall between 1.8 and 2.2 m (6–7 ft), and a 2 m animal weighs roughly 30–40 kg (65–90 lb).

Pups are born at 60–72 cm (24–28 in) and grow quickly during their first years, which helps them avoid the larger sharks that hunt along the slope. Growth then slows. In the best age study, carried out on longline catches off north-eastern Brazil, males reached maturity at about 1.85–1.9 m and eight years old, females at about 2.0–2.05 m and ten years. Females are the larger sex by a small margin, as in most members of the genus, and they carry the record.

The size bar below sets the 2.8 m maximum against a diver of average height: a big night shark is longer than a person, but it is a lightly built fish with a much slimmer body than a dusky shark of the same length.

Where night sharks live

The night shark is an Atlantic species with a range on both sides of the ocean. In the west it occurs from Delaware and, rarely, Massachusetts down the US east coast, through the Gulf of Mexico, the Bahamas and the Caribbean to Brazil and northern Argentina. In the east it is known from Senegal and the Gulf of Guinea south to Namibia. The strongholds are the deep water off Cuba, Puerto Rico and the Caribbean slope, and the shelf edge off Venezuela and north-eastern Brazil, where longline fleets have caught it for decades.

Habitat, rather than geography, is what keeps it out of sight. Night sharks live over the outer continental shelf and the upper slope, usually between 50 and 600 m (165–1,970 ft), and a few records reach about 2,000 m. They are mid-water animals rather than bottom dwellers: catches from Cuban longlines show the sharks holding at roughly 275–365 m by day and rising to around 180 m or shallower after dark, a daily vertical migration that tracks the fish and squid they eat. They come inshore only where deep water lies close to the coast, such as the edge of the Florida Straits.

Juveniles have been taken in somewhat shallower water than adults, and pregnant females appear to move away from the main aggregations, but no nursery area has been mapped.

What night sharks eat and how they hunt

Stomach contents from Cuban and Brazilian longline catches tell a consistent story: the night shark is a hunter of small, fast, schooling prey. Bony fish make up most of the diet, especially butterfish, flying fish, small mackerels and scads, mullet and sea basses, with squid the next most important item and shrimp taken when they are abundant. The small teeth and light jaws are not built for anything larger.

The common name comes from its feeding schedule. Cuban fishermen who worked the deep longlines of the 1930s to 1970s learned that catches rose sharply after sunset, when the sharks followed their prey up from the depths, and they set gear accordingly. Those oversized green eyes are the adaptation for this lifestyle: a large pupil and a reflective layer behind the retina gather the little light that reaches 200–300 m and let the shark pick out the flash of a fish school in near darkness. In deep water, as our page on shark vision explains, sight matters more than most people assume.

Smell and the electrical sense play their usual roles at close range. Like every requiem shark, the night shark has a snout studded with the ampullae of Lorenzini that detect the muscle twitches of prey in the final moments of an approach, and a lateral line that reads the pressure wave of a fleeing fish.

Behaviour: a shark that lives by the clock

Almost everything known about night shark behaviour comes from fishing gear rather than direct observation, because the species lives too deep for divers and is rarely kept in aquaria. The clearest pattern is the daily vertical migration described above: deep by day, shallower by night, repeated every 24 hours. The same rhythm shapes when and where the sharks are caught, and it is the reason a longline set at 200 m in the afternoon can come up empty while one soaked overnight at the same station is full of night sharks.

The species appears to be social, at least loosely. Longline catches often deliver several night sharks of similar size from one section of line, which suggests schooling by size, and catch data from Brazil show partial segregation by sex, with pregnant females turning up away from the main groups. Whether these are true schools or simply concentrations at good feeding spots is not known.

Movement over longer distances is undocumented; no satellite tag has been placed on a night shark. What is known is that, like other members of its family, the night shark must keep swimming to push water over its gills, so it never rests on the bottom. See how sharks breathe for why that matters for a species that lives in the low-oxygen layers of the slope.

Reproduction, growth and lifespan

The night shark is viviparous in the requiem-shark manner: each embryo drains its yolk sac and then attaches it to the wall of the uterus, forming a placenta that feeds it for the rest of the pregnancy. Gestation lasts about 12 months. Litters range from 4 to 18 pups, with 12 to 18 usual in the north-western Atlantic and smaller litters, often 4 to 12, reported off Brazil. The pups are born at 60–72 cm (24–28 in), which is large for a shark of this size and gives them a head start against predators.

Off north-eastern Brazil, where the most thorough study was done, mating and birth appear to be spread through much of the year, with a peak in pupping around the southern winter. Females probably rest for a year between pregnancies, though this has not been proved.

Age has been read from growth bands in the vertebrae. Males mature at about eight years and females at about ten, at roughly 1.85 m and 2.0 m respectively. The oldest sharks actually aged were around 17 years, and the growth curves fitted to those data give a theoretical maximum of about 28 years for males and 30 for females. That is a moderate lifespan for a requiem shark (compare the figures on how long sharks live), but the late maturity means each female may produce only a handful of litters in her life, which is the root of the species' conservation problem.

Is the night shark dangerous to people?

No. The SharkSider database contains no incident of any kind attributed to the night shark, and neither the International Shark Attack File nor the Global Shark Attack File lists one. The reason is simple geography: the species spends daylight hundreds of metres down along the continental slope and rises only at night, so it almost never shares water with a swimmer, surfer or diver.

The people who do meet night sharks are longline fishermen hauling them aboard, and a hooked 2 m shark thrashing on a deck can injure a careless crew member. That is a handling hazard, not predation. The one real risk the species poses to humans is on the plate: night shark flesh from the western Atlantic has tested high in mercury, and health authorities in Florida and Brazil have advised against eating it regularly, particularly for pregnant women and children. If you are curious about how rare bites really are, the Florida and Brazil attack pages show which species are actually involved along the night shark's coasts.

The SharkSider database has no incident attributed to this species. The database draws on the International Shark Attack File, the Global Shark Attack File and verified local reports, and is updated weekly.

Conservation status and threats

The IUCN Red List classes the night shark as Endangered, in an assessment dated 2019, with a decreasing population trend. The listing rests on catch records from the pelagic longline fisheries of the Caribbean, Venezuela and Brazil, where the species once made up a large share of the shark catch and has since declined steeply. Night sharks were the mainstay of a deepwater longline fishery off Havana from the 1930s, and catch rates fell by well over half before it contracted. Off north-eastern Brazil, where boats targeting tuna and swordfish take it as bycatch, catch rates dropped sharply between the 1990s and the 2000s.

The United States has done more than most. The National Marine Fisheries Service named the night shark a candidate species in 1997, a Species of Concern from 2004, and placed it on the prohibited list for the Atlantic shark fishery, so it cannot be landed or sold by US commercial or recreational fishers; a later review found the US population stable at a low level. Nowhere else in its range is it protected, and there are no catch limits in Caribbean or South American fisheries. Since November 2023 the entire requiem shark family has been on CITES Appendix II, so international trade in night shark fins or meat now requires export permits showing the catch was sustainable.

The threats are the familiar ones for an oceanic shark: longline bycatch in tuna and swordfish fisheries, demand for fins, a low reproductive rate and a lifespan long enough that each lost adult takes a decade to replace. Our page on why sharks are endangered sets these pressures in context.

Similar species and close relatives

The night shark belongs to Carcharhinus, the largest genus of requiem sharks, and its nearest neighbours in identification keys are the other slender, ridge-backed species of the Atlantic slope. The bignose shark (Carcharhinus altimus) shares the deep habitat and the interdorsal ridge but has a broad, blunt snout, conspicuous nasal flaps and a tall first dorsal fin. The silky shark is more oceanic, larger and smoother-skinned, with a long free tip on the second dorsal fin. The dusky shark and sandbar shark are heavier-bodied shelf species with shorter snouts; the sandbar's enormous first dorsal fin rules it out at a glance.

Green eyes are not unique to the night shark. The blue shark also has large eyes and a long snout, but it is a bright indigo, lacks the interdorsal ridge and has much longer, scythe-shaped pectoral fins. Small night sharks are sometimes confused with the blacknose shark in the Gulf of Mexico, though that species has a dark smudge on the snout tip and stays in shallow water.

• Bignose Sharkspecies profile
• Silky Sharkspecies profile
• Dusky Sharkspecies profile
• Sandbar Sharkspecies profile
• Blue Sharkspecies profile
• Blacknose Sharkspecies profile

Written and reviewed by

SharkSider Editorial Team

A small team focused on researching sharks and making marine biology easy to understand. Every page is reviewed against current species records and the SharkSider attack database, and updated when new incidents or research appear.

Published August 24, 2022 · Last updated September 22, 2026 · No incident attributed to this species in the SharkSider attack database, which is updated weekly.