It can be identified by its long, pointed snout and large, green eyes (when alive), and is dark grayish blue or brown above and white below.

Night sharks are quick, nocturnally active, schooling predators that feed mainly on small bony fishes and squid.

Reproduction is viviparous as with the other members of its family; females mate during the summer and give birth to litters of usually 12–18 pups after a gestation period of a year.

Because of its low reproductive rate and historically documented declines in areas such as the Caribbean, the night shark has been assessed as vulnerable by the American Fisheries Society.

[6] Fast and energetic, the night shark feeds primarily on small, active bony fishes such as mullet, mackerel, butterfish, sea basses, and flyingfish.

[4] Known parasites include the copepods Kroyeria caseyi, which attach to the gills,[9] Pandarus bicolor and P. smithii, which infest the skin,[4][10] and the tapeworms Heteronybelinia yamagutii, H. nipponica and Progrillotia dollfusi, which are found in the spiral valve intestine.

[8] Most information known about the night shark's life history comes from the subpopulation off northeastern Brazil, and may not hold true in other parts of the species range.

[12] Embryos at varying stages of development have been found in both February and June, suggesting that the parturition takes place over a span of several months.

[8] An important nursery area is believed to exist at the continental shelf break at 34°S latitude, near the southern extreme of this species' range.

This fast rate of growth serves to shorten the period immediately after birth when the small pups are most vulnerable to predators, a strategy similar to that employed by the silky shark (C. falciformis).

[2] Traditionally, it has comprised a part of the bycatch of pelagic longline fisheries targeting swordfish (Xiphias gladius) and tuna in the western Atlantic.

Since 1991, it has also been the focus of a longline fishery operating over seamounts off northeastern Brazil, where large numbers of sharks congregate and are easily captured.

[1][13] However, a study has found that night sharks from off northeastern Brazil accumulate high levels of mercury within their bodies, likely from their piscivorous diet.

[14] Therefore, eating only 0.1 kg (0.22 lb) of night shark meat per day could result in the ingestion of several times the daily mercury content judged safe by the World Health Organization.

[14] The International Union for Conservation of Nature has assessed the night shark globally as Endangered, citing its slow reproductive rate and historical declines under fishing pressure.

No fishery information on the night shark is available for the eastern Atlantic, leading to an IUCN assessment of data deficient for that region.

[15] Night sharks suffer high bycatch mortality on longlines, and prohibited or not, some are kept by fishers because of their value and the difficulty of identifying disembodied parts to species.