Sharks can also cover the tapetum lucidum by expanding cells that contain melanin to reduce light sensitivity in bright light. When approaching a prey item, sharks switch from one sense to another as they approach a potential prey item. Elasmobranchs in general have eggs with large yolks and thus produce fewer eggs. In oviparous forms, the fertilized eggs are deposited in a sac that gets entangled in algae. Development to hatching usually takes several months.
Some forms retain the eggs in the female's body until hatching.
In some cases, the mother continues to ovulate and the embryos eat the unfertilized eggs. Others develop long projections of the oviduct wall that enter the mouth and gill openings and secrete a milky fluid. However, once born there is no more parental care and the young are born as small versions of the adults. These have a benthic life style. Primarily eat benthic invertebrates many of which have shells, thus skates and rays are durophagus.