By Dennis Green Sex is one aspect of a shark 's life that cannot be sugarcoated. These terrors of the deep have vicious and brutal sex lives that pale in comparison to most mammalian sexual behaviors. The scientific truth of shark sex is not pretty and even harder to stomach — yet oddly fascinating.
In honor of Shark Week , brush up on the strangely dark sexual side of these finned creatures. We dug deep into shark expert Juliet Epstein's book Demon Fish to find out the truth behind these amazing creature's sex lives.
As if you needed more reasons to find sharks scary. Shark sex is extremely rough. Sex between sharks is rarely observed. Epstein quotes a rare eyewitness account of sharks mating in from A. Strachan, a fur seal observer with the New Zealand Department of Conservation: I had thought at the beginning they were fighting as one animal appeared to be attempting to grasp the other with its great mouth, making great gouges in its side. Larger species of male sharks bite the female to keep them close by during sex.
Epstein found that the use of biting to hold a female in place is nearly universal among species of sharks. It's usually easy to tell when a female has undergone mating, as she will have bite marks, raw skin and possibly even be bleeding -- basically the shark's idea of a hickey. The female blue shark species gets the worst of it, appearing severely wounded after mating season.
Not to worry, female sharks have evolved defenses to deal with the rough sex. To deal with the brutal copulation, female sharks have evolved to be larger than the males. Epstein describes their skin as rougher and thicker to deal with the pre-copulatory biting. Male sharks have two reproductive organs, called claspers. Though the claspers are paired, male sharks only use one at a time, depending on which side he "docks" into.
He is secured inside the female through tiny hooks that fasten to the cloaca. The claspers harden as the male sharks matures sexually. Female sharks stay in shallow water during mating season. Epstein describes this as one of the few ways female sharks have a choice when it comes to potential mates. The shallow water allows them to push their cloaca against the bottom of the ocean, making it hard for a male to flip her or roll her over to penetrate her. Sharks have multiple sexual partners at the same time.
Female sharks often mate with many males in the same session. Some sharks species, like lemon sharks or nurse sharks, give birth to litters with babies from several male parents.
Flickr, Ezio Armando 7. Sharks have been observed to reproduce asexually. When an egg is created, three "polar bodies" are also formed, acting as a waste material which usually is discarded over time. The polar bodies are genetically identical to the egg, and if one of the bodies fuses with the egg during the process of parthenogenesis development of an embryo without fertilization , it can form a viable embryo.
Since this is an unfertilized embryo, it only carries half the genetic variation of a traditionally fertilized egg.