Friday 17 May
Cownose ray (Rhinoptera bonasus)
Cownose ray fact file
- Find out more
- Print factsheet
Cownose ray description
With a conspicuous indent at the front of the head, and a specialised fin beneath the head divided into two, short rounded lobes, the cownose ray is one of the most readily identifiable ray species. Like other cownose rays, the body is disc-like, with large, broad pectoral fins forming pointed, wing-like structures along either side. A small dorsal fin is located at rear of the body, with a small, barbed poisonous spine situated directly behind it, beyond which the body tapers into a long whip-like tail (2) (3). The overall colouration of the cownose ray is light to dark brown above and white or yellowish-white below, with brownish edges on the pectoral fins. The mouth is located on the underside of the head and contains up to 11 to 13 rows of flattened, plate-like teeth, which enable the cownose ray to crush hard-shelled prey (2).
- Also known as
- Cowfish, skeete.
- Mourine Américaine.
- Cara De Vaca, Gavilan Mancha, Gavilan Manchado, Mancha, Raya Gavilán.
- Body width: 107 cm (1)
- Save Our Seas Foundation:
- IUCN Shark Specialist Group:
- Shark Research Institute:
- Shark Trust:
- Members of a group of aquatic molluscs, with soft parts encased in a shell consisting of two parts known as valves.
- Slightly salty water, usually a mixture of salt and freshwater, such as that found in estuaries.
- In the fishing industry, the part of the catch made up of non-target species.
- Dorsal fin
- The fin found on the back of the body of fish, or the raised structure on the back of most cetaceans.
- A diverse group of invertebrates, mainly marine, that have one or all of the following; a horny, toothed ribbon in the mouth (the radula), a shell covering the upper surface of the body, and a mantle or mantle cavity with a type of gill. Includes snails, slugs, shellfish, octopuses and squid.
- Pectoral fins
- In fish, the pair of fins that are found one on each side of the body just behind the gills. They are generally used for balancing and braking.
- Inhabiting the open oceans.
- IUCN Red List (June, 2009)
- Florida Museum of Natural History (July, 2009)
- Smithsonian Marine Station at Fort Pierce (July, 2009)
- Burnie, D. (2001) Animal. Dorling Kindersley, London.
- Sasko, D.E., Dean, M.N., Motta, P.J. and Hueter, R.E. (2006) Prey capture behavior and kinematics of the Atlantic cownose ray, Rhinoptera bonasus. Zoology, 109: 171 - 181.
- view the contents of, and Material on, the website;
- download and retain copies of the Material on their personal systems in digital form in low resolution for their own personal use;
- teachers, lecturers and students may incorporate the Material in their educational material (including, but not limited to, their lesson plans, presentations, worksheets and projects) in hard copy and digital format for use within a registered educational establishment, provided that the integrity of the Material is maintained and that copyright ownership and authorship is appropriately acknowledged by the End User.
Cownose ray biology
A pelagic and gregarious species (1), the cownose ray forms large schools which move gracefully through the water column propelled by undulations of the wing-like pectoral fins (4). Feeding takes place on the seabed, with the cownose ray detecting its prey by sensing movement as well as weak electric signals. In order to extract buried prey, the cownose ray sucks and vents water through the gills, thereby fluidising the surrounding sand, which is further cleared by stirring motions of the pectoral fins (2) (5). The food is then manoeuvred towards the mouth with the aid of the two lobes beneath the head, and sucked inside. Inside the mouth, it is crushed by the plate like-teeth and the edible parts separated from the indigestible parts, which are expelled through the mouth (5). Prey typically includes bottom-dwelling fish, crabs, lobsters and marine molluscs, such as bivalves (2). The large scale disturbance to the seabeds caused by the feeding behaviour of schools cownose ray have led to this species being implicated in extensive damage to seagrass beds and commercial shellfish beds (1). The cownose ray is preyed upon by a number of larger species such as cobia (Rachycentron canadum), sandbar sharks (Carcharhinus plumbeus) and bull sharks (Carcharhinus leucas) (2).
The cownose ray is believed to breed between June and October. Like many sharks and rays, the mode of reproduction is via ovovivipary, in which the females produce eggs, which after fertilisation hatch internally, so that the young are “born” live. While inside the uterus, the embryos are initially nourished by the egg yolk sac, but once hatched receive additional nourishment from a nutrient-rich fluid produced by the lining of the mother’s uterus. While one female was observed to carry six young to full term, in general the cownose ray produces only a single young, which is born measuring around 36 centimetres in body width (2).
The cownose ray makes long migrations in schools which can number thousands of individuals, moving northwards in late Spring and southwards in late Autumn (1) (2). Migration is believed to be initiated by the orientation of the sun and by water temperature (2)Top
Cownose ray range
The cownose ray inhabits warm temperate and tropical waters of the western Atlantic, occurring off the coast of southern New England, north-east U.S.A., south to the Gulf of Mexico, parts of the Caribbean and southern Brazil. It has been reported as being especially abundant in Chesapeake Bay, the largest estuary in the U.S.A., during the summer months (1).Top
Cownose ray habitatTop
Cownose ray status
Classified as Near Threatened (NT) on the IUCN Red List (1).Top
Cownose ray threats
In U.S.A. waters, the cownose ray population is not considered to by under threat. Although it is taken as bycatch by some fisheries, it is not directly targeted, and the population appears to be healthy (1). Nevertheless, a suggestion has been made by The Virginia Sea Grant Marine Advisory Program to implement a commercial fishery for this species, in order to reduce damage to seagrass and shellfish beds. As the cownose ray takes a relatively long time to reach reproductive maturity and usually produces only a single offspring, such exploitation could have severe adverse effects on the population (1) (2). In the Central and South American parts of this species’ range, it is presently considered to be more at risk due to intense, and generally unregulated, fishery activities. While a lack of catch data means that the exact impact on the cownose ray is unknown, other related ray species in the area have shown a significant decline (1).Top
Cownose ray conservation
Owing to the cownose ray’s long distance movements, it requires coordinated national and international efforts to ensure that its population is adequately assessed. In addition, estimates of mortality through fishing throughout its entire range are urgently necessary to assess the extent to which it is being affected. Given the heavy fishing pressure in Central and South American inshore waters, management strategies and regulation are likely to be required to ensure the survival of the cownose ray and other inshore ray and shark species in this area (1).Top
Find out more
To learn more about the conservation of sharks and rays visit:
AuthenticationThis information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact: email@example.comTop
MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.
Terms and Conditions of Use of Materials
Copyright in this website and materials contained on this website (Material) belongs to Wildscreen or its licensors.
Visitors to this website (End Users) are entitled to:
End Users shall not copy or otherwise extract, alter or manipulate Material other than as permitted in these Terms and Conditions of Use of Materials.
Additional use of flagged material
Green flagged material
Certain Material on this website (Licence 4 Material) displays a green flag next to the Material and is available for not-for-profit conservation or educational use. This material may be used by End Users, who are individuals or organisations that are in our opinion not-for-profit, for their not-for-profit conservation or not-for-profit educational purposes. Low resolution, watermarked images may be copied from this website by such End Users for such purposes. If you require high resolution or non-watermarked versions of the Material, please contact Wildscreen with details of your proposed use.
Creative commons material
Certain Material on this website has been licensed to Wildscreen under a Creative Commons Licence. These images are clearly marked with the Creative Commons buttons and may be used by End Users only in the way allowed by the specific Creative Commons Licence under which they have been submitted. Please see http://creativecommons.org for details.
Any other use
Please contact the copyright owners directly (copyright and contact details are shown for each media item) to negotiate terms and conditions for any use of Material other than those expressly permitted above. Please note that many of the contributors to ARKive are commercial operators and may request a fee for such use.
Save as permitted above, no person or organisation is permitted to incorporate any copyright material from this website into any other work or publication in any format (this includes but is not limited to: websites, Apps, CDs, DVDs, intranets, extranets, signage, digital communications or on printed materials for external or other distribution). Use of the Material for promotional, administrative or for-profit purposes is not permitted.