Episode Details

Basque sailors called them asesina ballenas, whale killers, and translation flipped the name to killer whale, though the orca is the largest dolphin. Males reach 33 feet and over 10 tons and hear their echolocation clicks through a hollow lower jaw. Pods hunt with local techniques: carousel feeding on Norwegian herring with bubbles and tail slaps, wave washing seals off Antarctic ice floes, and flipping great white sharks into tonic immobility to take their livers. In the North Pacific, fish eating residents live in large, noisy family groups, while mammal eating transients, or Bigg's orcas, hunt in silence. The two have not interbred for hundreds of thousands of years, and a 2024 study proposed splitting them into separate species.

Resident sons and daughters stay with their mothers for life, and females go through menopause and lead for decades as keepers of knowledge; Granny was estimated at 65 to 105 years old. Each pod has its own dialect and even fads, such as wearing dead salmon on their heads. Indigenous peoples of the Pacific Northwest revered orcas, but fishermen shot them, and the US Navy claimed to have killed hundreds off Iceland in 1956. In 1964 Moby Doll, harpooned for a museum model, survived in captivity and proved gentle. Michael Bigg's photo identification revealed fragile family populations.

• By 1970 about a quarter of orcas captured in Puget Sound bore bullet scars.
• Fifty Pacific Northwest orcas were captured for marine parks between 1964 and 1976.
• SeaWorld announced the end of its orca breeding program in 2016.
• PCBs build up in orca blubber through bioaccumulation, harming immune and reproductive systems.
• Southern residents depend on declining Chinook salmon and will not switch to eating seals.