Female rays carry fertilized eggs inside their bodies. The developing young are nourished by a yolk sac and by a milky liquid given off by the mother. The young are born as free-swimming miniature versions of their parents and must fend for themselves. Ray Relations Perhaps the most impressive group of rays are the mantas. Some kinds of manta rays stretch 20 feet across and weigh more than 3000 pounds.
Manta rays are active swimmers adapted for a cruising lifestyle.
They swim near the surface of the water, straining small animals with an elaborate meshwork in their gills. These giant filter feeders do not even have a barb and are harmless to people. Meeting the torpedo ray is a much more shocking experience. These small rays have electric organs on either side of their heads. Electricity is produced by modified muscle cells.