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Cownose Ray

Rhinoptera bonasus

Cownose rays swim by flapping their
Cownose rays swim by flapping their "wings" like a bird. As they swims, the tips of their fins break the surface and can look like shark fins. (Mr. T in DC/Flickr)

The cownose ray is a brown, kite-shaped ray with a long, whip-like tail. It is a highly migratory species along the Atlantic Coast that visits the Chesapeake Bay’s shallow waters in summer each year to give birth and mate.

Appearance:

The cownose ray's kite-shaped body has a wingspan of up to three feet and can weigh as much as 50 pounds. It varies in color from brown to olive green with a whitish belly and a long, brown tail that looks like a whip. Its squared, indented snout resembles a cow’s nose.

Habitat:

Live in schools near the surface of shallow waters, forming schools based on sex and age. Some schools can be very large.

Range:

Visit the lower and middle Chesapeake Bay from May to October, traveling as far north as Kent Island. Males leave the Bay in June-July for offshore waters. Females remain in the Bay until autumn, when they leave the estuary and migrate together with males to southern coastal waters.

Feeding:

Cownose rays are opportunistic feeders, eating whatever is available. In the Chesapeake Bay, they eat mostly softshell clams, macoma clams and razor clams, but they will eat oysters and hard clams when available. They find their prey by flapping their fins against the bottom to uncover buried shellfish, then using their powerful dental plates to crush the shells open. Although recent diet studies have shown that oysters and hard clams were not found to be large parts of the cownose ray's diet, intensive feeding on oysters or clams can occur.

Predators:

Cobia, bull sharks and sandbar sharks are known predators of cownose rays.

Reproduction and Life Cycle:

Mating takes place in June or July each summer. After mating, male cownose rays leave the Bay while females stay until October. After an 11-month gestation period, females give birth to a single live young, called a pup, in mid-June the following summer. At birth, pups are about 11 to 18 inches long. After birth, mating occurs and the cycle begins again.

Other Facts:

  • Cownose rays have been referred to as an invasive species, when in fact they are not.
  • The cownose ray is sometimes called a “doublehead” because of the indentation around its snout.
  • This ray swims by flapping its fins like a bird. As it swims, the tips of the fins break the surface and can look like shark fins. Many “shark” sightings in the Bay are actually cownose rays.
  • Cownose rays are have venomous spines at the base of their tails. Captain John Smith learned about the cownose ray’s spine the hard way. During his 1608 voyage he was stung so severely that his crew thought he was going to die. The site on the Rappahannock River where he was stung is still known today as “Stingray Point.”
  • Although cownose rays are sometimes referred to as skates or stingrays, they are technically neither. Cownose rays belong to their own family of rays.

Sources and Additional Information:




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