A single litter of shark pups can have anywhere from one to five dads, according to a new study that sheds light on the complex sex and family lives of many sharks.
Multiple paternity appears to be very common among sharks and has been documented in at least six species so far: leopard sharks, small-spotted catsharks, bonnethead sharks, lemon sharks, nurse sharks and sandbar sharks.
The most widely accepted explanation for multiple paternity is what's known as "convenience polyandry."
"Basically, the female doesn't have much say about who she mates with," lead author Andrew Nosal of Scripps Institution of Oceanography's Marine Biology Research Division told Discovery News. "If a male encounters her and wants to mate, he will."
"At this point, the female has two options," Nosal continued. "She can attempt to fight and escape, but may incur greater injury in the process. Or she can acquiesce to minimize physical damage to her body...As a matter of convenience, to minimize the chance of injury, the female may just go along with it, even though there appears to be no biological need to mate with more than one male per reproductive cycle."