Most fish species have a bony skeleton. The skeleton of an undulate ray, however, is made of cartilage, like that of the sharks to which it is closely related.
Undulate rays have a vivid pattern of swirling brown stripes and yellow and white spots on their skin, which camouflages them against the sandy seabeds on which they live. Their rounded, flattened bodies grow up to 1m in length, and they have a thin, whip-like tail that is almost the same length again. Their backs and tails are spiny for protection from predators (they are harmless to people), and they also have prickly skin on their undersides.
Undulate rays are found in comparatively deep water, from 50-200m depth, and they eat a variety of bottom-dwelling prey including crabs.
Undulate rays produce oblong eggs with pointed horns at the corners, and lay them into the sand, mud or gravel seabed. Because they lay only a few eggs they are vulnerable to fishing, as it takes a long time for the population to recover when numbers begin to decline.
Undulate skate, undulate painted ray
In British waters, the undulate ray is most common in the English Channel, although its distribution also includes the west coast of England and Wales and most of Ireland. Its wider European range is the eastern Atlantic from Morocco to southern Ireland, and the western Mediterranean.
UKBAP priority species
Species of principal importance for the purpose of conserving of biodiversity under the Natural Environment and Rural Communities Act 2006
Undulate ray Fishbase website
Raja undulata World register of marine species (WoRMS)
Undulate ray - Raja undulata Marine life information network
Skates Cefas website
Like sharks, to which they are closely related, undulate rays have a skeleton made of cartilage.