Ninja Lanternshark

• Maximum lengthAbout 52 cm (20 in); males examined were around 32 cm
• WeightNo published measurement; a few hundred grams at most
• LifespanUnknown; no ageing study exists
• Depth range836–1,443 m (2,740–4,730 ft) on the continental slope
• DietUnstudied; probably small crustaceans, squid and lanternfish
• IUCN statusLeast Concern (assessed 2019)

How to recognise a ninja lanternshark

Most lanternsharks are two-toned: a brown or grey back, a black belly and a sharp-edged black mark on the flank above the pelvic fins, with lines of tiny light organs, the photophores, drawn along the underside. The ninja lanternshark abandons the pattern. It is black from snout to tail, above and below, with no distinct flank mark, and its photophores are fewer and more scattered than in its relatives, concentrated on the head and the underside. That uniform darkness, and the way the pale patches around the eyes and mouth stand out against it, produced the name.

Otherwise it is a typical small Etmopterus: a slim, soft-bodied shark with a short blunt snout, very large green-reflecting eyes, five small gill slits and a spiracle behind each eye. There are two dorsal fins, each with a grooved spine in front of it, the second spine longer than the first and the second fin larger, and no anal fin at all, a feature shared by every shark in the order Squaliformes and a quick way to tell a lanternshark from a catshark of the same size.

The teeth differ between jaws, as in all lanternsharks. Upper teeth are small, with a central cusp and one or two pairs of side cusplets; lower teeth are broad, blade-like and hooked, with 30 to 36 across the lower jaw, and they overlap to form a single cutting edge. Sibling species in the same ocean, such as the blackbelly lanternshark, keep the two-toned pattern, so a wholly black lanternshark from the Central American slope is, so far, this one.

How big is a ninja lanternshark?

The whole species is known from eight preserved specimens plus whatever has been caught since, so the size figures are exact for those animals and provisional for the species. The largest is a female of 515 mm, a little over 51 cm (20 in) in total length. The males in the original series were much smaller, about 32.5 cm (12.8 in), and it is not clear whether they were fully grown; in lanternsharks males are typically somewhat smaller than females at maturity, but a gap this wide probably means the collection simply lacked large males.

No specimen was weighed for publication. A 50 cm lanternshark is a slender, watery animal with a large oily liver and thin muscle, and comparable species of that length weigh a few hundred grams. Size at birth is unknown, because no pregnant female has been examined, and by analogy with the velvet belly lanternshark and its relatives a newborn would be somewhere around 10 to 15 cm. The size bar below compares the 52 cm maximum with a 1.8 m diver.

Where ninja lanternsharks live

The type specimens were collected in 2010 during a Spanish research trawl survey of the Pacific continental slope of Central America, and every capture location falls in a narrow band off Nicaragua, Costa Rica and Panama, at depths between 836 and 1,443 m (2,740 to 4,730 ft). That is the deep slope, far below the reach of light, in water of roughly 4 to 6 °C with little oxygen and enormous pressure. Nothing suggests the species ranges into shallower water.

Whether the true range is larger is an open question. The eastern Pacific slope from Mexico to Peru has been sampled only patchily at these depths, and lanternsharks are small enough to slip through many survey nets, so the species may well extend north or south along the same contour. Until someone catches one elsewhere, however, the range is exactly what the map would show: a strip of deep seabed along the Pacific side of the Central American isthmus. No country page on this site lists a shark at 1,000 m, so the automatic range list below is empty.

The trawl records say a little about habitat: the bottom in that depth band is soft sediment on a canyon-cut slope, and the sharks were taken on or close to it, which suggests a bottom-associated life rather than the mid-water habit of some lanternsharks.

What ninja lanternsharks eat and how they hunt

Nobody has published a stomach analysis, so the diet is inferred. Every lanternshark that has been studied eats the small animals of the deep scattering layer and the slope floor: krill and other shrimp-like crustaceans, small squid, and small fish, above all lanternfish, the abundant finger-length glowing fish that migrate up and down the water column each night. The ninja lanternshark's mouth, teeth and body match that menu.

The hunting method is a guess informed by anatomy and by its relatives. The hooked, overlapping lower teeth are built for gripping and slicing soft prey rather than crushing shells. The very large eyes gather what little light exists, much of it produced by other animals, and the lateral line and ampullae of Lorenzini pick up movement and the electrical fields of prey at close range in the dark. A small black shark that emits almost no light of its own would be nearly invisible to a lanternfish looking up or sideways, which is presumably the point: the original description suggested that the reduced photophores and black skin let the shark approach prey unseen, and that idea, more than any stealth on its part, is what earned it the ninja name.

Feeding rhythm is unknown; whether it rises off the bottom at night to follow the migrating layer, as Atlantic lanternsharks do, has not been tested. Its own predators are undocumented but would include larger squaloid sharks and big deep-water bony fish (see what eats sharks).

Behaviour, light and senses

The defining trait of the family is bioluminescence. Lanternsharks carry thousands of photophores, tiny light-producing organs in the skin, and use them for counter-illumination: the belly glows faintly blue-green at the same intensity as the light filtering from above, so the shark's silhouette disappears to anything looking up from below. The species-specific flank patterns are thought to help individuals recognise each other, and the glowing spines may warn off predators.

The ninja lanternshark has fewer photophores than its relatives and no flank pattern, which is unusual and not fully explained. One reading is that at 800 to 1,400 m there is so little downwelling light left that counter-illumination brings small return, and a black skin that reflects nothing is the cheaper form of camouflage. The photophores that remain, clustered on the head and underside, may still serve to blend the outline of the head or to signal to other ninja lanternsharks. No living individual has been observed, so these are hypotheses.

Everything else about its behaviour is inferred from the group. Lanternsharks are sluggish swimmers that hover and cruise slowly, sometimes in loose schools sorted by size and sex; they are neither territorial nor migratory over long distances, although several species move vertically each day. The huge eyes, backed by a reflective layer, are tuned to the blue-green wavelengths of residual sunlight and bioluminescence, and vision is probably the leading sense at the moment of a strike.

Reproduction and lifespan

No pregnant ninja lanternshark has been examined, so the reproductive mode is taken from the genus. Every Etmopterus whose breeding is known is aplacental viviparous, the mode the older books call ovoviviparous: the eggs are fertilised internally, develop inside the mother on their yolk alone, with no placenta and no extra egg feeding, and the pups are born fully formed (see the four ways sharks reproduce). The original description assumed the same for this species, and there is no reason to doubt it.

Litter size in related lanternsharks runs from about six to twenty, with the smaller species at the lower end, and pregnancies in the cold deep sea are slow, likely a year or more; a female probably breeds only every second or third year. Newborns of a 50 cm species would be roughly 10 to 15 cm. Where the ninja lanternshark gives birth, whether it has a nursery depth, and in what season, are all unknown, and the eight type specimens included both sexes but no obviously pregnant female.

Age is a blank. Lanternsharks are hard to age because their vertebrae are poorly calcified, and the few estimates available for the family, from the velvet belly and the southern lanternshark, suggest maturity at several years and lifespans of one to a few decades, slow for so small an animal (see how long sharks live). The ninja lanternshark, living in colder and deeper water than either, is unlikely to be faster. A shark that matures late and produces a dozen pups every few years is vulnerable to any fishery that reaches it.

Are ninja lanternsharks dangerous to people?

No, in every sense. The SharkSider database contains no incident attributed to this species, the International Shark Attack File has none, and there is no scenario in which one could occur. The ninja lanternshark lives at least 800 m down, in water no diver reaches, and the only people who have ever touched one are the scientists who lifted the type specimens out of a research trawl. It is half a metre long, soft-bodied, and armed with teeth designed for lanternfish.

If anything, the danger to a person would come from the two dorsal spines, which in lanternsharks are sharp enough to prick a careless hand sorting a catch, and which are mildly venomous in some squaloid sharks. That is a hazard for a deck crew, not for a bather. The species will never appear on our shark encounter advice for the simple reason that no one will ever encounter it by accident.

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

The IUCN Red List assesses the ninja lanternshark as Least Concern (assessed 2019). That may sound generous for a species known from so few specimens, but the logic is sound: it lives below the depth at which commercial fishing operates on the Pacific slope of Central America, its known range lies partly within waters where deep trawling is minimal, and there is no fishery that targets lanternsharks anywhere in the region. It is not listed on CITES or the Convention on Migratory Species, and no country protects it specifically.

The caveats are the usual ones for deep-sea sharks. Deepwater fisheries have a habit of moving deeper as shallower stocks decline, and lanternsharks elsewhere, in the north-east Atlantic and off southern Africa, have been caught in large numbers as bycatch in trawls and on longlines, then discarded dead or rendered for liver oil. A species with a small range, slow growth and small litters would have little resilience if that happened off Central America. If the true range extends along the slope from Mexico to Peru the species is safer than the map suggests; if it is confined to a few hundred kilometres of seabed it is more exposed.

For now the practical conservation measure is knowledge. Every deep-sea survey in the eastern Pacific that identifies its lanternsharks to species adds to the map, and the discovery of this shark in a routine trawl is a reminder of how much of the shark fauna at depth is still uncounted. Our broader page on why sharks are endangered sets out the pressures its relatives face.

Similar species and close relatives

The genus Etmopterus is the largest shark genus alive, with around forty named species and new ones still being described, most of them small, dark and hard to tell apart. The ninja lanternshark's nearest ecological neighbours are the other eastern Pacific lanternsharks: the blackbelly lanternshark, a widespread two-toned species that overlaps its depth range, and the dwarf lanternshark of the Caribbean, which at about 20 cm is the smallest shark in the world. The Caribbean lanternshark lives on the Atlantic side of the same isthmus.

The best-known members of the family are Atlantic: the velvet belly lanternshark of European slopes, the species in which most of what we know about lanternshark bioluminescence was worked out, and the green lanternshark of the Gulf of Mexico. The splendid lanternshark and southern lanternshark show the typical flank markings the ninja lacks. Further afield in the same order, the cookiecutter shark is a glowing squaloid that has turned bioluminescence into a hunting lure, and the kitefin shark is the largest luminous vertebrate known.

• Blackbelly Lanternsharkspecies profile
• Dwarf Lanternsharkspecies profile
• Caribbean Lanternsharkspecies profile
• Velvet Belly Lanternsharkspecies profile
• Green Lanternsharkspecies profile
• Southern Lanternsharkspecies 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 19, 2022 · Last updated September 22, 2026 · No incident attributed to this species in the SharkSider attack database, which is updated weekly.