The velvet dogfish (Zameus squamulosus) is a small deep-water shark of the sleeper shark family that reaches about 84 cm (2.8 ft) and turns up in tropical and temperate waters of every ocean, usually between 400 and 900 m. It is slender and blackish-brown, with a flattened head, a small narrow mouth, no anal fin and tiny grooved spines almost buried in the skin ahead of both dorsal fins.
Its diet is mainly lanternfish and squid. Females bear live young after the eggs hatch internally, but no litter has ever been counted and no age has ever been read from its vertebrae. The IUCN lists the species as Least Concern on the strength of its enormous range. It has never been connected to an injury to a person.
- Maximum length84 cm (2.8 ft)
- WeightNo reliable published maximum; a few kilograms
- LifespanUnknown; no ageing study exists
- Depth rangeSurface to 2,200 m (7,220 ft); usually 400–900 m
- DietLanternfish, squid and deep-sea invertebrates
- IUCN statusLeast Concern (assessed 2019)
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Chondrichthyes
- Order
- Squaliformes
- Family
- Somniosidae
- Genus
- Zameus
- Species
- Zameus squamulosus
- Family (common)
- Sleeper sharks
- Also known as
- Velvet dogfish shark, Smallmouth velvet dogfish
On this page
How to recognise a velvet dogfish
The name is a description, not a flourish. Run a hand along the flank of this shark and the skin gives back a soft nap rather than a rasp, because the dermal denticles are small, lance-shaped and packed so closely that the points never catch. The scientific name says the same thing: squamulosus means covered in little scales.
The shape is a slim cylinder. The head is flattened on top and ends in a short, bluntly pointed snout; the mouth beneath it is narrow and nearly straight, which is the feature that separates Zameus from most of its relatives at a glance. The body tapers to a long, low tail with no keel. Colour is uniform black to chocolate brown, without markings, blotches or the pale flank streaks that lanternsharks carry.
Fins and teeth
There are two small dorsal fins, each with a tiny grooved spine at the front that is so short it is often hidden in the surrounding skin, and no anal fin at all. In the jaws the two halves do completely different jobs: the upper teeth are narrow, upright spikes for holding, the lower ones broad interlocking blades that form a single cutting edge. That combination is standard across the sleeper sharks, including the far larger Portuguese dogfish. Our guide to shark anatomy explains the terms used here.
How big do velvet dogfish get?
Not big. The largest specimen on record measured 84 cm (2.8 ft) in total length, and most of the sharks that reach a laboratory bench are considerably shorter than that. Mature males are generally between about 50 and 59 cm, mature females between roughly 59 and 69 cm, so the great majority of adults are under 70 cm and would fit in a kitchen sink.
Females run larger than males at maturity and at maximum, which is the usual pattern in the dogfishes and follows from the demands of carrying a litter internally. Beyond that the size record is thin: no length at birth has been published, and the sample of measured animals across the whole world is small enough that the true maximum may well be greater than 84 cm.
No weight for this species has ever reached print. A slender 80 cm shark with a large oil-filled liver and lightly built cartilage would be a matter of two or three kilograms, most of that liver, which is the organ that holds the animal in the water column without effort. Our page on how much sharks weigh explains why deep-sea species are so much lighter than their length suggests. The scale bar underneath puts that 84 cm maximum next to a 1.8 m diver.
Where velvet dogfish live
Almost everywhere, and almost nowhere. Records exist from the Atlantic, Indian and Pacific oceans between roughly 68°N and 56°S, taking in the waters off Japan, Australia, New Zealand, South Africa, Brazil, the mid-Atlantic ridge and the north-eastern Atlantic. But the records are single specimens scattered across that enormous area, and no one can say whether the species is genuinely continuous between them or whether several similar sharks are being lumped together.
Vertically the range is just as broad. Captures run from the surface down to about 2,200 m, with the bulk between 400 and 900 m. The shallow records are almost all nocturnal and oceanic, from pelagic longlines set far from land, while the deep ones come from gear worked on or near the slope floor. That points to a shark that is not strictly bottom-living at all but moves up through the water column after dark, following the same layer of lanternfish and squid that the whole deep-sea food web rises with.
Nothing is known about population structure, seasonal movement or whether individuals stay in one ocean basin. A species collected this rarely across this much water is, in practice, a species nobody has ever studied in one place.
What velvet dogfish eat
Stomach contents from the handful of examined specimens point to midwater prey: lanternfish and other small bony fishes, squid, and probably shrimps and other invertebrates taken near the bottom. This is the standard menu of the deep scattering layer, the dense band of small animals that rises towards the surface each night and sinks again at dawn, and it fits a shark that is caught both at 2,000 m and at the surface after dark.
The jaws are built for it. A narrow mouth with spike-like upper teeth is a trap for something soft and slippery, and the interlocking lower blade lets the shark cut a piece from prey too large to swallow whole. There is no crushing surface anywhere in the mouth, so hard-shelled prey is unlikely to feature much.
Hunting in permanent darkness means the eyes are a secondary instrument. A velvet dogfish locates prey with the lateral line, which registers the wake of a swimming fish, with an acute sense of smell, and with the electroreceptive ampullae of Lorenzini that pick up the muscle activity of an animal at close range. The final strike is a short lunge rather than a chase; nothing about this shark's slack musculature and unkeeled tail suggests speed, and in an environment this poor in food, the energy cost of a chase rarely pays.
Behaviour, senses and what is still unknown
No living velvet dogfish has ever been observed, filmed or kept. This section is therefore an account of what the anatomy implies and where the gaps are, which is more honest than the alternative.
The build is that of a slow, neutrally buoyant drifter. Deep-sea squaliforms of this size carry a liver that may be a fifth or a quarter of body weight, filled with low-density squalene oil, which removes the need to swim to keep station. A shark equipped that way can hang motionless for long periods and then move with very little effort, which is the only viable strategy in water where food arrives irregularly.
The vertical spread of capture depths is the strongest behavioural clue available: an animal taken at 2,000 m and also on surface longlines at night is almost certainly making a nightly vertical migration of over a kilometre, in company with the prey it eats. Whether it is luminous is not established — several of its squaliform relatives are, and the subject is covered on our page about bioluminescence in the sea — and nothing is known about its social behaviour, courtship or aggregation. Larger deep-water sharks and big predatory fish are the likely threats; our page on what eats sharks covers the usual candidates.
Breeding and lifespan
Velvet dogfish are aplacental viviparous, the mode also called ovoviviparity: eggs hatch inside the mother, each embryo is supported by its own yolk sac, and the pups are born fully formed with no placental connection and no supply of extra eggs. Every member of the sleeper shark family that has been examined reproduces this way, and the few pregnant velvet dogfish recorded are consistent with it.
The detail stops there. No complete litter has been counted, so the number of pups is unknown. The gestation period is unknown, the length at birth is unknown, and no breeding season, mating ground or nursery area has ever been identified. Relatives of similar size in the family carry small litters, often fewer than ten, after gestations believed to exceed a year, which is the closest thing to a guide that exists.
Age and growth
The age of this species has never been read. Its vertebrae have never been sectioned and counted, no growth curve has been fitted, and no age at maturity has been proposed. The wider pattern in deep-water squaliforms is unambiguous, though: slow growth, late maturity and lifespans that run to several decades in species barely a metre long. The Greenland shark, the extreme case in the same family, has been dated to well over 250 years. Our overview of how long sharks live puts that range in order.
Are velvet dogfish dangerous?
No. A velvet dogfish is shorter than a metre, has a mouth a few centimetres wide, and lives in water that is normally hundreds of metres below any diver. Even the shallow nocturnal records come from open ocean far from any coast where people swim. No record in the SharkSider database is attributed to it, and none is conceivable.
Handling carries the usual dogfish caveats and nothing more: the tiny dorsal spines can prick a careless hand, and the skin, velvety as it is in one direction, will still abrade in the other. Fishery crews who bring one up are more likely to be puzzled than alarmed, since most have never seen the species before, and the shark itself is usually dead on arrival from the pressure change rather than in any condition to object. Nor does the species carry any of the secondary risks sometimes attached to sharks: it is not known to bite gear, it does not follow vessels, and it is far too small to interest anyone as a trophy. Of the roughly 540 sharks on our list of shark types, this is among the several hundred that have no interaction with people at all.
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 assessed the velvet dogfish as Least Concern in 2019. The case rests almost entirely on distribution: a species recorded from three oceans, across nearly 120 degrees of latitude and 2,000 m of depth, is difficult to threaten globally even if any one part of its range is fished hard. There is no directed fishery for it anywhere, no CITES listing and no national protection.
The shark is taken occasionally on deepwater longlines and in the pelagic tuna longline fisheries that work the open ocean, and it appears in deep trawl bycatch on some slopes. Because it has no market value, it is discarded, usually dead. Nowhere is it recorded to species in landings data, which means a decline would not be visible in any catch series even if one were happening.
That is the real weakness behind a comfortable listing. Deep-water sharks share a life history — slow growth, late maturity, tiny litters — that leaves almost no capacity to rebound, and the last three decades have shown how quickly a species can be depleted once trawlers reach its depth band. The kitefin shark was considered secure before a liver-oil fishery cut it back, and several of this shark's own family have followed. Our page on why sharks are endangered explains why absence of evidence is weak reassurance in the deep sea.
Close relatives and look-alikes
The velvet dogfish sits in the family Somniosidae, the sleeper sharks, and was for many years placed in the genus Scymnodon, which is why older books list it as Scymnodon squamulosus. Its nearest confusions are family members of similar size and colour: the longnose velvet dogfish, which has a distinctly longer snout and a wider mouth, the roughskin dogfish, whose overlapping plate-like denticles feel nothing like velvet, and the heavier-bodied Portuguese dogfish, the deepest-living shark of the north-eastern Atlantic.
At the other end of the family scale are the true sleeper sharks of the genus Somniosus: the little sleeper shark, close in size to this species, and the enormous Greenland shark, which shares the same body plan stretched to five metres. Outside the family, the small black deep-sea dogfish most often mistaken for this one is the velvet belly lanternshark, which shares part of the name but belongs to the lanternsharks and carries a sharp black flank marking this species never has.
- Longnose Velvet Dogfishspecies profile
- Portuguese Dogfishspecies profile
- Roughskin Dogfishspecies profile
- Little Sleeper Sharkspecies profile
Greenland Sharkspecies profile- Kitefin Sharkspecies profile
Frequently asked questions
How big does a velvet dogfish get?
The largest recorded specimen measured 84 cm (2.8 ft) in total length. Most adults are shorter: mature males run about 50 to 59 cm and mature females about 59 to 69 cm. No length at birth and no weight have been published, though a large individual would weigh only two or three kilograms.
Why is it called the velvet dogfish?
Because of the skin. Its dermal denticles are small, lance-shaped and packed so tightly that the surface feels like brushed felt rather than sandpaper. The scientific name makes the same point: squamulosus means covered in little scales. Dogfish is the general term for the small sharks of the order Squaliformes.
Where do velvet dogfish live?
In tropical and temperate parts of the Atlantic, Indian and Pacific oceans, between roughly 68°N and 56°S. Records are scattered single specimens rather than concentrations. Captures run from the surface down to about 2,200 m, with most between 400 and 900 m on or near the continental slope.
What do velvet dogfish eat?
Mainly lanternfish and other small midwater fishes, plus squid and probably shrimps taken near the bottom. The narrow mouth combines spike-like upper teeth for holding with an interlocking lower blade for cutting, so prey larger than the mouth can still be fed on. Few stomachs have ever been examined.
How deep do velvet dogfish go?
Records extend from the surface down to about 2,200 m, one of the widest depth ranges of any small shark. The great majority of captures fall between 400 and 900 m. Shallow records come almost entirely from pelagic longlines set at night far offshore, which suggests a nightly vertical migration.
Do velvet dogfish lay eggs?
No. The eggs hatch inside the mother and the embryos live on their yolk sacs until birth, with no placental connection, a mode called aplacental viviparity or ovoviviparity. No complete litter has ever been counted for this species, so the number of pups, the gestation period and the size at birth are all unknown.
How long do velvet dogfish live?
Nobody knows. No vertebrae from this species have been sectioned and aged, so there is no growth curve and no maximum age. Deep-water sharks of comparable size generally grow slowly, mature late and live for several decades, which is the only frame available until someone does the work.
Are velvet dogfish dangerous to humans?
No. They are under a metre long, have a mouth a few centimetres wide, and live hundreds of metres down in open ocean far from any swimming beach. No entry in the SharkSider database names this shark. The tiny spines in front of the dorsal fins can prick a hand, and that is all.
Are velvet dogfish endangered?
No. The IUCN assessed them as Least Concern in 2019, mainly because their range spans three oceans and a huge depth band. They are caught occasionally by deepwater and tuna longlines and discarded, but no fishery targets them. Nowhere are they recorded to species in landings, so a decline would go unseen.
Is the velvet dogfish the same as the longnose velvet dogfish?
No, they are different species in the same family. The longnose velvet dogfish has a noticeably longer snout and a broader mouth, grows larger, and is far more frequently caught in north-east Atlantic deepwater fisheries. The velvet dogfish is the smaller, rarer and much less studied of the two.
References
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 November 2, 2022 · Last updated September 22, 2026 · No incident attributed to this species in the SharkSider attack database, which is updated weekly.
