Killer whales learn how to hunt by practising drowning each other

Telegraph

5 days ago

Orcas practise drowning their friends as a way to learn how to hunt large prey like blue whales.
Footage captured by film crews off the coast of Australia shows a pod of killer whales honing their hunting skills in a world first.
Young orcas surround their mock prey, which is a fellow pod member playing the role of a hunted beast, before forcing it underwater and covering its blowhole.
The blowhole on the back of whales is what allows the orca to breathe and if they can not reach the surface often enough they will run out of oxygen and drown.
Video of the behaviour was captured for the first time by BBC staff recording the new Parenthood documentary narrated by Sir David Attenborough.
The clips, shared with The Times, show a matriarch leading the macabre lesson with young orcas off the coast of Bremer Bay in Western Australia.
'This is not a game,' Sir David says as the footage plays.
'One deliberately stops swimming in order to enable the others to practise a particular skill. They push it beneath the surface and submerge its blowhole to prevent it from breathing.
'They are practising the actions they will use to drown their prey. And these orca need to be on top of their game. They hunt the largest animals that have ever lived: blue whales.'
The camera crew then show the animals putting the lessons into action as they attack a blue whale which was caught off guard.
This species of whale can weigh more than 100 tonnes and measure up to 30 metres in length, making it the biggest animal ever to have lived.
They are too large for almost all predators in the world to hunt but the lessons of the orcas and their shared might and nous pose a threat to the giant of the seas, which can hold its breath for about half an hour.
The show airs on Aug 3 and took three years to film. It covers a range of animal behaviours related to the raising of young.
A BBC spokesman said: 'Specialised underwater gimbals and tow cameras were used to bring cameras alongside hunting orcas underwater. This technology allowed the crew to travel at the same speed as the orca hunting pack and provided new insights into their behaviour.
'The practice-hunting behaviour appears to show members of an orca family submerging the head of one individual to prevent it from breathing - the technique used by killer whales to hunt large whales.
'This practice-hunting behaviour has never been filmed before.'
Another revelation in the show is that the African social spider eats its mother after they are born and raised by them.
A colony of more than 1,000 of the spiders were recorded on camera hunting their own mothers in a startling case of mass matricide.
Jeff Wilson, the series' director, said this cannibalistic arachnid behaviour is his favourite from the series.
'My personal favourite must be the story of the African social spider, a mother spider who not only raises 50 offspring alongside her sisters but eventually sacrifices her own body to feed her growing young in an act called matriphagy.'
He added: 'The level of commitment required to raise young, that no individual's needs are the same, that the benefit of a good home, food and teaching are all part of raising successful offspring.
'In a world that is changing all around us in ways that none of us can predict, we can learn how to deal with uncertainty - because in the natural world, nothing is certain, and animal parents are still incredibly successful.'