A sand tiger shark (Carcharias taurus) in the Indian Ocean. (Photo credit: Peter Pinnock/Getty Images)
Scientists have uncovered the secrets of shark sex off the coast of North Carolina by studying the terrifying bites they receive during mating.
Shark sex is not for the faint of heart, as males are forced to squeeze their bodies as they penetrate females. In smaller species this happens quite quickly, but larger sharks are less agile and have difficulty holding their position, so males often grab females with their teeth, leaving bloody marks on their bodies.
Many males don't escape unscathed, either. Some females bite during mating, according to a new study published Dec. 4 in the journal Environmental Biology of Fishes.
By studying the bites of both males and females, researchers can pinpoint with great accuracy the time and location of mating, which in the wild usually remains hidden.
“Observations of mating in any species of shark or ray are extremely rare, so we used mating wounds as indirect evidence of their reproductive behavior,” lead study author Jennifer Wyffels, a researcher at Ripley’s Aquarium and the University of Delaware, told Live Science via email. “Sharks and rays use their mouths to hold and position females, so mating wounds are common during the reproductive season.”
However, there are few detailed descriptions of such wounds in the scientific literature, so researchers have limited knowledge about this aspect of shark reproduction, Wyffels notes.
For their study, Wyffels and his team examined mating wounds in sand tiger sharks (Carcharias taurus), an endangered species that can grow up to 3 meters in length and is found in coastal waters around the world.
The researchers first observed a group of sand tiger sharks in an aquarium where they witnessed a mating match in which the female suffered serious injuries. The deepest wound cut through the female's skin and exposed the muscle underneath, but the wound healed quickly, the researchers noted in their paper.
Based on the data collected, the researchers then developed a scale from 1 to 4 to rate the severity and stages of healing of wounds sustained during shark mating: 1 being fresh wounds, 2 and 3 being intermediate stages of healing, and 4 being the beginning of the scarring process.
Sourse: www.livescience.com
