Everything you ever wanted to know about sex and seduction in the underwater realm #1 : Shark Sex
Shark Sex: 6 bizarre facts
#1 The boys have got two.
Male sharks have two sexual members! They are called claspers. The babies are born with an obvious pair not of veg but of sausages. Though phallic shaped these two appendages are in fact more like a rolled-up fin. Indeed, they are formed by the elongation then inner curling of the pelvic fin. The males only actually use one clasper, which are equipped with spurs to make sure they stay in once in (ouch), at a time. Whether having two improves sexual prowess is yet to determined, female sharks don’t kiss and tell.
#2 Special sex teeth, special sex skin.
Male sharks have developed a special set of sex teeth that only the males have and only in mating season, mind. These teeth are for biting down and holding on to the female’s pectoral fin during intercourse (lest they escape?). The love bites marks left on the females back tell quite a story of violent sex. In an evolutionary retaliation against this (and to avoid all the females going for the virgin birth option -see below) the female’s skin is much ticker than the male’s and able to withstand the latching on by razor sharp denticles (and they also heal very fast). Who said you didn’t have to be thick skinned to be female in this world?
#3 Who needs males anyway?
Sharks have nothing to envy the Virgin Marie. After experiencing the love bites explained above, it’s no small wonder certain female sharks decide to forgo males altogether and make babies alone. This type of reproduction is called parthenogenesis and does not require any male involvement or male DNA. The baby inherits only the mother’s DNA. An unfertilised egg just spontaneously develops into an embryo. Scientists think this may be the last evolutionary defence in species with critically dwindling numbers where finding a mate can be complicated. It has been observed in certain shark and ray species. It is, however, not a solution for endangered species since it could lead to skewered sex ratios (babies are all female) and lack of genetic diversity.
#4 Pregnancy, the brutal war within
It’s dog (fish) eat dog (fish) world out there, from the moment of conception for sharks, no fœtus is safe from his bother. In sand tiger sharks, who have two wombs, the top dog in each womb eats his brothers and sisters whilst still being gestated! Scientists believe this is a winning strategy not only for the pups but also for the mother. Indeed, scientists have noted that the winners in each uterus are usually full siblings, fathered by the same male. The theory goes that once the female has had sex with the first male (the chosen one with the genetic qualities she wants), the later males end up siring nothing more than food for these first alpha embryos. This means the female does not need to waste energy on mate avoidance and can mate with inferior suitors without fear that future fertilisations will interfere with the quality of her offspring.
#5 When the cum shot needs more power
Shark penises, as described above, are really only curled up fins lacking an internal tube, like a urethra in mammals, to carry the sperm from the tests to the tip. The sperm would just drip out - not very effective or impressive technique, right? - if it were not for a clever little muscle and sea water. The muscle sucks in the sea water and stores it in a siphon sack which then allows the shark to squeeze the sac as he ejaculates and squirt both water and sperm down his claspers into Mrs. Shark. Who said water guns weren’t sexy?
#6 Saving sperm for later
Sharks have a quality that will make them envied by female populations the world over. They can store sperm for later. No chance of getting pregnant by that one night stand you met a 22, you could store his sperm and decide to become pregnant by him up to 4 years later! In terms of offspring quality, female sharks can store one suitors’ sperm until they find a better option with higher grade genes and then just flush the old sperm out and keep the better one in...how very practical.
Information in this blog post mostly gleaned from http://www.sexinthesea.org by Marah J Hardt