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Leopard seals have been observed in Southern Chile performing a two-hour courtship that included a variety of vocal calls. Credit: Christopher Michel, CC BY 2.0.
If you thought dating other humans was complicated, wait until you hear about the complex courtship behaviors of wild leopard seals. These apex predators are the second largest Antarctic seal species after southern elephant seals. At 8 to 11 feet long and weighing up to 1,300 pounds, their only natural predators are orcas. These ice-loving pinnipeds are notoriously difficult to study, but a team of researchers led by a Baylor University biologist managed to observe a two-hour courtship interaction between a male and female in Laguna San Rafael, Chile.
As with many species, the male leopard seal did most of the work, while the female spent her time lying out on the ice, even remaining completely still for nearly an hour and a half of the interaction. The male, meanwhile, remained underwater, spending less than 15 minutes of the whole interaction at the water’s surface. While underwater, he made 65 vocal calls toward the female, which included low-double trills, high-double trills, and other types of trills—a sort of vibrating warble that sounds a bit like a long-winded frog. She responded with seven of her own calls, including some growls, blasts and “thump pulses,” in which she vibrated her throat, neck and chest while lying down.
The researchers continued to hear underwater calls for another 8 hours after leaving the area. The next day they observed the male with a swollen genital opening, suggesting that the male likely attempted to mate with the female, but it wasn’t clear if he succeeded. What was clear, given these observations and sightings of newborns and pups in the area, is that leopard seals are mating in South America, beyond their usual stomping grounds of the Antarctic pack ice.
