Various water animals become part of diet of stingrays. Small species eat worms, benthic mollusks, crayfish, crabs, small octopuses. Large catch fish: their victims are often sardines, haddock, capelin, mullet, flounder, cod, eels, salmon. But the huge manta, on the contrary, eats plankton and the smallest fish. Its prey is simply filtered out, passing water through the gills. However, the most unusual methods of fishing practice electric and sawtooth stingrays, or fish-saws (not to be confused with pirate sharks!). The first have electrical organs, controlled by a special department of the brain.
“Batteries” are able to accumulate a charge and at the right time to discharge, with a current strength of 7-8 amperes, the voltage for different species can reach from 80 to 300 volts. For small animals, such an electric shock is fatal, for a person at best, very painful, at worst – can cause long-term paralysis of the limbs. As for fish-saws, her snout is stretched in the form of a board, poked at the edges with sharp teeth. With the help of this tool, a sawtooth ram is digging in the ground, loosening it, and bursting into a flock of fish, beats on the sides and deafens its victims.
It is interesting that the stingrays along with their closest relatives sharks have an extremely developed reproductive system. When multiplying, they either lay egg capsules, or give birth to live cubs. In the first case, the female lays 1-2 eggs with a break in 1-5 days. The cycle of reproduction can stretch for months, during this period one adult manages to postpone from 4-5 to 50 eggs. Each egg is clad with a cornea, the corners of this sachet end with filaments, with their help the egg capsule is attached to the soil or algae. Development of the embryo in different species lasts from 4 to 14 months.
This is a very long period for fish, but the eggs are not coming from the male, but the fully formed young stingray. In viviparous species fry develop in the mother’s body in a special organ, similar to the uterus of mammals. The main source of nutrition for them is the yolk of the egg, in addition, the embryos suck liquid, which is secreted by the processes of the “womb”. This way of feeding is similar to feeding milk in animals.
