Spined Pygmy Shark

• Maximum lengthAbout 25 cm (10 in); females 22 cm, males 15 cm
• WeightA few tens of grams; no formal record
• LifespanUnknown
• Depth range200–500 m (650–1,640 ft); records to about 1,200 m
• DietLanternfish, bristlemouths, dragonfish, squid
• IUCN statusLeast Concern (assessed 2019)

How to recognise a spined pygmy shark

The first thing anyone notices is the size: an adult male is about the length of a pencil and a large female is shorter than a school ruler. The body is a slender spindle, thickest just behind the head and tapering to a narrow tail stalk, and the snout is long, conical and slightly bulbous. The eyes are large for the animal, with a straight lower rim and an angled upper lid, and behind each is a small spiracle.

Look next at the fins, because they settle the identification. The first dorsal fin is tiny and set well forward, above the rear of the pectoral fins, and it carries a spine; in males the spine is exposed and easy to see, in females it is buried under the skin and shows only as a bump. The second dorsal fin is low, long-based and spineless, sitting over and behind the pelvic fins. That single spine is the feature that separates the genus Squaliolus from every other kitefin shark: the pygmy shark and the cookiecutter have no spines at all. There is no anal fin, and the tail is broad and paddle-shaped with the two lobes nearly equal.

Colour is blackish brown above and below, with a clear pale edge to every fin. The underside is studded with minute photophores from the snout back to the tail. The teeth are unequal: 22 to 31 rows of narrow, smooth, upright points in the upper jaw and 16 to 21 rows of broad, knife-like, interlocking blades in the lower.

How small is the spined pygmy shark?

Small enough to compete for the title of smallest shark on Earth. Males are mature at about 15 cm (6 in) and do not grow much beyond it; females mature at 17 to 20 cm and the largest reliably measured reach about 22 cm (8.7 in). A handful of older records give 25 cm, and one figure of 28 cm circulates in the literature, but that last one has never been confirmed and may belong to another species, so the honest maximum is around 25 cm. Only the dwarf lanternshark and the smalleye pygmy shark are in the same class; our list of the ten smallest sharks puts them side by side.

Weight has never been formally recorded because nobody weighs a fish this size at sea, but a 20 cm animal with a large oily liver would be a few tens of grams, lighter than a smartphone. Pups measure 9 to 10 cm (3.5 to 3.9 in) at birth, which is already well over half the adult male length and shows how little growing this species does after it is born. The size difference between the sexes is real and consistent: in every sample the females are the larger sex by a third or more.

Where spined pygmy sharks live

The spined pygmy shark has one of the widest and patchiest ranges of any shark. In the western Atlantic it is known from Bermuda, the slope off the eastern United States and the Gulf of Mexico, Suriname, southern Brazil and northern Argentina; in the eastern Atlantic from the Bay of Biscay off France, Madeira, the Azores and Cape Verde; in the western Indian Ocean off Somalia; and in the western Pacific from southern Japan through Taiwan to the Philippines, where the first two specimens were dredged from Batangas Bay by the US Fisheries steamer Albatross. The gaps between those records almost certainly reflect where deep-water surveys have been made rather than where the shark is absent.

What the records have in common is productive water over a steep bottom. The species keeps to continental and island slopes, outer shelves and seamounts rather than the open ocean gyres favoured by its cousin the pygmy shark, and it is caught most often where upwelling or current boundaries concentrate the lanternfish it eats. By day it holds at around 500 m; by night it rises to about 200 m, so the usual depth band is 200 to 500 m (650 to 1,640 ft), with a few records to around 1,200 m. Water at those depths is 5 to 12 °C, so this is a cold-water shark even in the tropics. The map below shades the areas with confirmed records.

What spined pygmy sharks eat

The stomachs that have been examined tell a consistent story: this is a hunter of the deep scattering layer, the dense band of small fish and squid that rises toward the surface every night and sinks again at dawn. Lanternfish make up the bulk of the diet, with bristlemouths and dragonfish alongside them, and small squid of the genera Histioteuthis and Chiroteuthis add the rest. All of these are animals of a few centimetres, matched to a mouth that is only a centimetre or two across.

The teeth show how it feeds. The narrow upper teeth pin a fish while the broad, interlocking lower blades slice through it, so a pygmy shark can take a bite out of a prey item almost as long as itself rather than having to swallow it whole. That is the same tooth plan the cookiecutter shark uses to gouge plugs from tuna and dolphins, scaled down to lanternfish size, and it is why the family is grouped together.

Hunting takes place mostly in the dark. The large eyes gather what little light remains at 200 m at night, and the shark's own belly lights, described in the next section, hide it from the prey below. Beyond that, nothing has been observed directly: nobody has watched a spined pygmy shark hunt, and everything here is read from stomach contents, net depths and anatomy.

Behaviour, vertical migration and living light

The defining behaviour is the nightly commute. Trawl catches place the species near 500 m in daylight and near 200 m after dark, a round trip of some 600 m every 24 hours for an animal shorter than a hand. It follows the lanternfish and squid that make the same journey, and the timing is set by light: the sharks rise as the surface dims and sink as it brightens.

Its most remarkable feature is the light it makes itself. The underside carries thousands of tiny photophores, from the tip of the snout to the tail, that glow a faint blue-green. This is counter-illumination: the glow matches the dim light filtering down from above, so that a predator looking up from below sees no dark silhouette against the surface. Many deep-water sharks share the trick, and our page on bioluminescent sharks explains the chemistry; what is unusual in Squaliolus is how far forward the light organs extend, right around the eyes and snout.

The rest of its biology is built for economy. A huge oily liver gives near-neutral buoyancy, so the daily migration costs little energy; the skeleton is reduced to about 60 vertebrae, fewer than any other shark and less than half the count of a typical requiem shark; and the flat, smooth denticles reduce drag. In the dark the big eyes and the lateral line matter more than the nose; our shark anatomy page covers how each sense works. Social behaviour is unknown.

Reproduction and lifespan

The spined pygmy shark is aplacental viviparous, the mode most books call ovoviviparous: the eggs hatch inside the mother, the embryos live on their yolk sacs with no placenta, and the young are born fully formed. A female has two working ovaries, each able to hold up to a dozen large yolky eggs, but the litters that have actually been seen are far smaller than that potential. The clearest record is a female caught off southern Brazil in 1999 that carried four near-term pups, and litters of a few pups are probably the rule.

Pups are born at 9 to 10 cm (3.5 to 3.9 in). Males mature at about 15 cm, females at 17 to 20 cm, which for a species that grows to little more than 20 cm means maturity comes with most of the growing already done. Gestation, breeding season, breeding interval and nursery areas have never been recorded, and no age study exists, so the lifespan is unknown. Our page on how long sharks live shows how wide the range is across the group.

The species itself has been known only since 1912, when Hugh Smith and Lewis Radcliffe described it from those two Philippine specimens, the type being a 15 cm adult male. Little has been added to the life history since.

Are spined pygmy sharks dangerous?

No. This is a shark you could hold in your palm, with a mouth about a centimetre wide and teeth made for lanternfish, living hundreds of metres below the deepest recreational dive. Nobody has ever met one while swimming, and the SharkSider database has no incident attributed to the species. It cannot bite a person in any meaningful way, and even the single dorsal spine, a few millimetres long, is no threat to a fisherman's glove.

The only people who handle spined pygmy sharks are the crews of research vessels and deep-water trawlers sorting a catch, and the animal is the one at risk in that meeting: it comes up dead or dying from the pressure and temperature change and is usually discarded. If you are worried about sharks at a beach, our guide to surviving a shark encounter deals with the handful of large species that matter; this is not one of them.

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 classed the spined pygmy shark as Least Concern in 2019, and for once the label is reassuring rather than a sign of missing data. The species has a near-global range, lives mostly deeper than commercial trawls work, is too small to have any value as food, fins or liver oil, and slips through the mesh of most nets that do reach its depth. Where it is caught, in deep-water shrimp and finfish trawls off Brazil, in the Bay of Biscay and off Japan and Taiwan, it is bycatch that is thrown back, and the numbers involved are small.

No country protects it, no fishery targets it and no CITES or CMS listing covers it, which is appropriate for a species with no identified threat. The one caveat is that nobody has ever estimated its population, so the assessment rests on the absence of pressure rather than on evidence of abundance. Expansion of deep-water fishing onto seamounts and slopes could change that picture, as it has for larger deep-sea sharks, and the reasons are set out on our page on why sharks are endangered.

For now it is a rare good-news story: a shark too small, too deep and too widespread to be worth anyone's while.

Similar species and close relatives

The kitefin family (Dalatiidae) holds ten small to medium sharks, and three of them could be confused with the spined pygmy. The nearest is its congener the smalleye pygmy shark (Squaliolus aliae) of the western Pacific and eastern Indian Ocean, which is a little smaller, has noticeably smaller eyes with a different lid shape, and a shorter snout; where the two overlap off Japan, Taiwan and the Philippines they are separated on those characters. The pygmy shark (Euprotomicrus bispinatus) is the same size and colour and also glows, but has no dorsal spine, a first dorsal set further back, and prefers the open ocean of the southern hemisphere. The longnose pygmy shark (Heteroscymnoides marleyi) is rarer, spineless and has a much longer snout.

Further out in the family are the cookiecutter shark, twice the length and famous for the round plugs it bites from whales, tuna and the occasional swimmer; the taillight shark, known from a handful of specimens with a glowing gland under its tail; and the metre-long kitefin shark that gives the family its name. Among unrelated sharks, the tiny lanternsharks of the genus Etmopterus, such as the dwarf lanternshark, are the same size and also luminous but carry a spine on both dorsal fins and belong to a separate family.

• Smalleye Pygmy Sharkspecies profile
• Pygmy Sharkspecies profile
• Longnose Pygmy Sharkspecies profile
• Cookiecutter Sharkspecies profile
• Kitefin Sharkspecies profile
• Dwarf 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 27, 2022 · Last updated September 22, 2026 · No incident attributed to this species in the SharkSider attack database, which is updated weekly.