The Tennessee Aquarium announced on Friday it captured a rare mating interaction between two sand tiger sharks, also known as grey nurse sharks.
A male shark was caught giving “love bites” to a female shark on the webcam in the aquarium’s 618,000-gallon Secret Reef exhibit in the last days of January and early February.
To humans, the ritual may appear bizarre and a little scary, but it proves to be quite utilitarian. Male sand tigers must fertilize the female’s eggs internally, so they use their one tool – teeth – to orient themselves and their partner for successful fertilization during mating.
If the sharks are facing the same direction, the male will typically grab the female by the large fin that sticks out of her side and contort his body around her, according to Thom Demas, the aquarium’s director of aquatic collection and life support systems. If the female isn’t facing the right direction or hasn’t accepted the male’s advances, he’ll use a “toothsome embrace” to reorient her. Even though the bites look aggressive and often leave marks, female sand tigers are able to withstand the affection.
“It appears pretty vicious, but that’s how these sharks reproduce,” Demas says. “They’re designed for this. Their skin is made of tough ‘scales’ called dermal denticles and can be much thicker than males. While they do get some injuries during mating, they’re usually superficial, and they heal.”