Seven Worlds, One Planet – Sir David Attenborough’s next nature documentary – airs tonight in the UK at 6:15pm on BBC One. There will be seven episodes in total, each episode focusing on one of earth’s unique continents. With wildlife encounters from over 40 countries, this series aims to depict the vivid beauty of nature once again whilst conveying a key message of conservation. The first episode will take us to the world’s largest desert – Antarctica.
For the next seven weeks, I am going to be writing about an animal from the continent being explored in Seven Worlds, One Planet. This week, I have chosen one of the most fearsome predators found in Antarctica – the leopard seal (Hydrurga leptonyx). Aptly named, this marine mammal gets its name from its black-spotted coat and stealthy hunting technique. Found throughout the freezing waters surrounding Antarctica, the leopard seal is the second largest species of seal in the area (after the southern elephant seal). They are pagophilic (ice-loving) as they spend their time at the edge of Antarctic pack ice.
Formidable hunters, leopard seals feed on a range of prey – including fish, krill, cephalopods, penguins and even other seals. In fact, they are the only species of seal that actively hunts warm-blooded prey. They often ambush their prey. For instance, when hunting penguins, they wait patiently underwater near an ice shelf and grab the birds just as they enter the water. The penguins don’t even have the chance to react. Although leopard seals have very few natural predators, they are not invisible. Orcas will hunt leopard seals given the chance.
Leopard seals have developed a multitude of adaptations for survival within their harsh and perilous environment. They have a thick layer of blubber which helps them to stay warm in the freezing Antarctic waters, as well as making them more streamlined in the water. This provides great agility, allowing them to keep up with their prey. Furthermore, leopard seals are highly adept divers. They are able to collapse their lungs to dive deeper than 80m in search of food. Also their trachea (windpipe) is reinforced to prevent it from collapsing at these extreme pressures.
Due to their isolated environment, there is still much more to learn about the fascinating behaviours of leopard seals. I am hoping that tonight’s episode will give us a deeper insight into the lives of these seals, as well as their ecological importance. Although no humans live in Antarctica, our actions thousands of miles away still have a huge effect on its wildlife and stability.
Hennessy, K., Wiggins, V. (2014) Animal Encyclopedia: The Definitive Visual Guide. 2nd edn. London. Dorling Kindersley.
Seven Worlds, One Planet Trailer: https://www.youtube.com/watch?v=nm5XasUl7HM