Mammals viewers are convinced orcas are 'true villains' of nature

What did you miss?

The latest episode of Sir David Attenborough's documentary series Mammals followed the experiences of mammals living in or around water. This meant a return to Attenborough's spotlight for one of the world's most efficient predators: the killer whale.

We saw a pod of six orcas as they targeted humpback whale calves on a migration route in shallow waters off the coast of Australia. One calf travelling with its mother ended up on the wrong end of some seriously efficient hunting.

Who, what and why?

The orcas' arrival came as an enormous shock to viewers. A placid scene of the humpback whale mother escorting her calf was interrupted when an enormous orca dived in to attack the calf, like a jump scare in a horror movie. The mother immediately attempted to ward off the killer whales by swishing her tail and fins.

Unfortunately for the humpback family, the orcas had a variety of tricks on hand to secure the calf as their prey. While some of the orcas distracted the mother, others repeatedly rammed into the calf as it was being carried on her back.

Once the calf had been separated, the orcas carried it on their own backs, essentially kidnapping it and mimicking the behaviour of its mother before going in for the kill.

Viewers were left stunned by the sudden horror of the initial attack and definitely took against the creatures for their Machiavellian plan to separate the calf from its mother and her defensive abilities. This was especially true when Attenborough revealed that the orcas sometimes only eat the tongues of the calves and leave the rest for sharks.

Of course, these scenes just go to show how remarkable the orca is as a species, whether viewers are on their side or not. Mammals producer Daniel Rasmussen wrote for the BBC website about the team's surprise at witnessing a whole new hunting tactic.

"This completely new methodology shocked the crew and underlined just how incredible mammals are; when presented with a problem they can design, communicate and execute a plan as a team," he said.

Rasmussen added: "It's exciting that one of our greatest living predators, and one of most intelligent animals on Earth, is still surprising us."

What else happened on Mammals?

This aquatic episode of Mammals also introduced viewers to false killer whales, which have developed a symbiotic relationship with dolphins in which they share food. Elsewhere, the unique adaptations of the star-nosed mole and toque macaque showed the benefits of being able to find something to eat both above and below the water.

Then, in some of the most spectacular scenes of Mammals so far, the show followed enormous sperm whales as they dived vertically into the depths in order to track down giant squid. It also showed the horrific impact of fishing debris on these animals, with Attenborough once again highlighting the damage human beings do to the natural world.

Mammals continues on BBC One at 7pm on Sundays.

Read more:

• David Attenborough's Mammals shows 'cruel' fate of desert foxes

• Mammals viewers horrified by gruesome Easter bunny scenes

• Planet Earth III: Green turtle's tough journey back to sea leaves viewers in tears

Watch: Trailer for David Attenborough series Mammals