Bowmouth guitarfish
Rhina ancylostoma
A heavy, patient ray with a shark-like tail, resting low over sand and coral. Bowmouth guitarfish are rare, and every sighting is a privilege, never a promise.
Critically Endangered (IUCN, 2019) means it faces an extremely high risk of extinction in the wild. The assessment found declines of more than 80% across its range over about 45 years, with fishing the main pressure.



Photos show the species, not always the places on this page.
Length
Most sources give up to about 2.7 m (8.9 ft); FishBase lists a maximum of 3 m (9.8 ft). Newborns are about 45 to 51 cm (18 to 20 in). Animals seen in Djibouti were about 2 m or more.
Weight
Listed at up to about 135 kg (298 lb). Females grow larger than males.
Next to a person
A big adult is about 1.5 times as long as an adult person is tall, and about as heavy as two adults.
What it eats
Bottom-living fish such as croakers, plus crabs, prawns, shellfish and cephalopods. It crushes its food with low, blunt teeth.
Around people
Calm, look only
How it lives
It lives on sandy and muddy seabeds near reefs and wrecks, from about 3 to 90 m. The young develop inside the mother, nourished first by yolk, and litters are 2 to 11 pups, usually about 4, born at about 45 cm. Males mature at about 1.5 to 1.8 m and females above about 1.8 m. FishBase rates its population resilience as very low, with a doubling time of more than 14 years.
Where it goes
Not well tracked. It is described as a strong swimmer that drives itself with its tail like a shark, more active at night and not territorial. In the Gulf of Tadjoura, Djibouti, divers recorded it every November to February over seven seasons between 2015 and 2023, mostly on sand and coral at 20 to 40 m, which suggests animals return to the same area.
We only draw a journey on the map when scientists have tracked it or clearly documented it. For this animal we have not found one yet.
Populations
Critically Endangered (IUCN, 2019). A 2023 study in Djibouti, citing the IUCN, reports declines of more than 80% across its range in the last 45 years. Numbers have fallen substantially in Indonesian waters. It is listed on CITES Appendix II. A regional assessment lists it as Near Threatened in Australia, where turtle excluder devices on trawlers are reported to have helped. In the Gulf of Tadjoura there were 23 sightings over seven seasons (2015 to 2023, with 2020 to 2021 missed), with up to 7 or more at once on 13 January 2017. No global population count was found.
Meet it respectfully
Look only. Never chase, touch, grab or corner a bowmouth guitarfish, and never feed or bait it. It is a strong swimmer with thorns on its head and back. Stay off the seabed so you do not stir up sand or crowd it, and let it choose where to go. It is rare and is seen on a predictable season in some places, but no one can promise a sighting.
Fun fact
Tap the bulb to light it up.
It is a ray with a shark-like tail and tall, sickle-shaped dorsal fins, so it is also called a shark ray.
Rows of thorns run above the eyes and along the back and shoulders, and are used in defence.
Its fins are highly prized, and it is caught in trawls, gillnets and line fisheries.
Bowmouth guitarfish in the Ocean Atlas
Places we have researched where this animal is recorded. It is never guaranteed, and some places are for watching from the boat only.
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Sources for this page
- Wikipedia, Bowmouth guitarfish
- FishBase, Rhina ancylostoma
- Boldrocchi et al., 2023, Biology
- Fishes of Australia, Shark Ray
- Zenodo, Rhina ancylostoma taxonomic treatment
- GBIF, IUCN category lookup
Facts checked 5 October 2026. Photos: Unsplash licence, or Creative Commons as shown on each photo.
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