|Scientific name||Rhinoptera bonasus|
|Length||45 inches (1.1 meters)|
|Wingspan||4.0 feet ( about 1.3 meters)|
|Weight||50 pounds (23 kilograms)|
|Life span||16 to 18 years|
|Gestation||11 to 12 months|
|Number of young at birth||1 pup|
|Size at birth||11 to 18 inches (28 to 46 cm)|
|Age of maturity||4 to 5 years|
What makes us different from other stringrays?
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.
How do we eat?
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 maneuvered 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 marinemolluscs, such as bivalves (2). The large scale disturbance to the seabeds caused by the feeding behavior 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)
Like many sharks and rays, the mode of reproduction is via ovovivipary, in which the females produce eggs, which after fertilization hatch internally, so that the young are “born” live.
Do Cownose rays migrate?
Cownose rays school and migrate in large groups, sometimes up to thousands of individuals. They are strong swimmers and can migrate long distances. Scientists believe that the migrations may be triggered by seasonal changes in water temperature and sun orientation.
Cownose rays are near threatened, due to heavy (and generally unregulated) fishing pressure on the inshore environment throughout large parts of Central and South America.
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