Cownose Ray

The Cownose Ray (Rhinoptera bonasus) is a member of the eagle ray family (Myliobatidae), named for its uniquely indented, two-lobed snout that resembles a cow's nose. It is best known for forming large migratory schools, sometimes numbering in the hundreds to thousands, that travel along the coastlines of the western Atlantic and Gulf of Mexico. These schools move seasonally in response to water temperature, spending warmer months in shallow bays and estuaries and moving offshore or southward as waters cool. Cownose rays are durophagous predators, using flattened tooth plates to crush hard-shelled prey, and are considered Near Threatened due to targeted and incidental fishing pressure.

• Disc: rhomboid, wider than long, with sharply angled pointed wingtips
• Snout: distinctively notched into two rounded lobes, unlike the single pointed snout of most rays
• Color: brown, olive, or greenish-brown above, white to pale cream below
• Tail: long, thin, whip-like with a single venomous barb near the base
• Size: disc width typically 70 cm to just over 1 m

The bilobed "cow-nose" snout readily separates this species from other eagle rays and stingrays, which have a single rounded or pointed snout.

Cownose Rays occupy warm temperate to tropical coastal waters of the western Atlantic, from New England south through the Gulf of Mexico to Brazil. They favor shallow bays, estuaries, and sandy or muddy nearshore flats during warmer months, often in water only a few meters deep, and move into deeper continental shelf waters during seasonal migrations. Large schools travel considerable distances along the coast each year, tracking warm water and prey availability, and are notably absent from an area once temperatures drop, moving south or offshore for the winter.

Cownose Rays are highly social, forming some of the largest known aggregations of any ray species, with schools sometimes stretching for kilometers during seasonal migrations. They feed primarily on bivalves, crustaceans, and other hard-shelled invertebrates, using their flattened crushing tooth plates and often excavating pits in soft sediment while foraging. Their schooling behavior may offer protection from predators such as large sharks and serves to synchronize migration and reproduction. Reproduction is viviparous with a placental-like yolk-sac connection, and females typically give birth to a single pup after an extended gestation, resulting in low reproductive output relative to their abundance.