Leopard seals (scientific name Hydrurga leptonyx) are carnivores, meaning their diet consists primarily of meat. These predators are the second-largest seal species in the Antarctic and are apex predators within their icy habitat. Their specialized adaptations allow them to thrive in the challenging polar environment, making them effective hunters.
What Leopard Seals Eat
Leopard seals exhibit a diverse diet, adapting to prey availability across seasons and regions. While known for preying on warm-blooded animals, their diet also includes smaller marine life. Younger leopard seals often consume more krill, squid, and fish, with krill sometimes making up a significant portion of their intake, potentially up to 83% in areas where larger prey is less abundant.
As they mature, their diet expands to include a variety of larger prey. They are well-known for hunting penguins, including species like Emperor and Adélie penguins. Leopard seals also prey on other seal species, such as Weddell seals and the pups of Crabeater and Fur seals. Many Crabeater seals, for instance, bear scars from leopard seal attacks, indicating frequent predatory interactions, especially on younger individuals.
How Leopard Seals Hunt
Leopard seals employ various hunting strategies. They are often ambush predators, waiting near ice floes for unsuspecting penguins. Once a penguin is seized, the seal thrashes the bird against the water’s surface to remove its skin and feathers before consuming it. This method efficiently dismembers their prey.
Their streamlined bodies and powerful foreflippers enable them to move with speed and agility underwater, reaching speeds of up to 40 kilometers per hour (25 mph). This speed is crucial for chasing swift prey like fish. While typically solitary, cooperative hunting has occasionally been observed, particularly when targeting larger prey such as fur seal pups. These instances might involve a mother and her older pup, or male-female pairs, working together to increase hunting success.
Specialized Physical Traits
Leopard seals possess unique adaptations for their Antarctic environment. They have powerful jaws and a wide gape, allowing them to seize and subdue prey. Their teeth are distinctive, featuring long, sharp canine teeth up to 2.5 centimeters (1 inch) long, used for gripping and tearing flesh.
Beyond their sharp front teeth, their molars (postcanines) are trident-shaped and interlock, functioning as a sieve. This specialized dental structure allows them to filter small crustaceans like krill from the water, similar to how baleen whales feed. Their streamlined body shape and large, powerful foreflippers contribute to their speed and maneuverability in the water, aiding rapid acceleration and precise turns while hunting. Their large eyes are adapted for excellent vision in dim underwater light, and their short, sensitive whiskers (vibrissae) help them detect subtle movements, even in low visibility.
Their Role in the Antarctic Food Web
Leopard seals are apex predators in the Antarctic marine ecosystem. They influence the populations of various prey species, including penguins, other seals, and fish, contributing to the region’s ecological balance. Their diverse diet, ranging from small krill to large seals, connects multiple trophic levels within the food web.
Individual leopard seals can exhibit dietary specialization, focusing on particular prey types, which can have localized impacts on prey populations. For instance, a small number of large female leopard seals have been observed to be responsible for a substantial portion of fur seal pup predation in certain areas. Their presence on ice floes also links marine and ice habitats, playing a part in nutrient cycling. The only natural predator of the leopard seal in this ecosystem is the orca.