5. They seem to be “sleep swimming,” with parts of their brain being less active, or "resting," while the shark … And if a shark was already hanging out … There's a kernel of truth in there. Most sharks have long gestation (pregnancy) periods, some species like Basking Sharks and Frilled sharks have a gestation period of three years. As environments changed, sharks … Sharks are easily taught a simple action. But there was a small study done in the late ‘60s that found sharks in the open ocean weren’t interested in menstrual blood (and in fact were only interested in human gut liquid, of all things). The myth stems from the false notion that dolphins are the natural enemies of sharks, and that sharks will do anything to avoid them. However, blood from sharks’ real prey (sea otters or cetacean) did move the sharks into a feeding frenzy, Collier added. I wonder what do you all think: do sharks get attracted to female blood or they can sense the difference between injury blood and the period? "Sharks in the Jurassic period often had teeth with a flat-ridged surface to make it easier to crunch on crunchy things," says Whitenack. It is true that many types of sharks must keep moving in order to receive life-giving oxygen from the water passing through their gills. Little is known about the mating rituals of sharks, as they are difficult to observe. Instead of breathing air, though, sharks get oxygen from the water that surrounds them. So frequency of … Some of those myths are kind of funny (no, sharks aren’t more attracted to people on their periods), but overall, having so much mystery surrounding menstruation is straight-up harmful. Shark species that need to swim constantly to keep water moving over their gills seem to have active periods and restful periods, rather than undergoing deep sleep as we do. And there are loads of female divers and surfers who report being in the ocean around sharks on their period … All of this means that sharks probably won’t pick up on your period from two miles away and make a beeline for your uterus. Sharks do engage in periods of rest throughout the day, but it is much different from the kind of sleep that other animals engage in. I once trained a whitetip reef shark to swim towards me over a piece of pink coral. When she did it correctly I rewarded her with a piece of fish. Sharks don't have lungs, but they do have to breathe oxygen to survive. Shark mothers do not take care of their young. TRUE: Sharks can be trained. Sharks do not have to be on their side or back when feeding; they can bite from any angle. Shark behavior expert Ralph S. Collier once tested to see if wild sharks were attracted to menstrual blood and other bodily fluids, but found that the only liquid that elicited a reaction was liquid from the abdominal cavity ― not menstrual blood, according to Mother Jones. The concentration of oxygen in water is much lower than in air, so animals like sharks have developed ways to harvest as much oxygen as they can. EGGS DEVELOP INSIDE THE MOTHER (OVOVIVIPARITY) Most sharks have ovoviviparous embryonic development, as the eggs hatch within the oviduct of the female although she does not provide any food directly; the young feed on the egg yolk of the yolk sac and the fluids that the walls of the oviduct secrete. Shark Mating Habits. Sharks do not sleep the same as humans do, at least not in a deep sleep as humans do, half of their brain stays active while the other half is in a light ‘sleep’, meaning they’re oscillating between wakeful and restful periods throughout the day.