World's oldest known killer whale presumed likely dead

The world's oldest killer whale, a 100-year-old animal affectionately known as Granny, is missing and presumed dead, scientists say.
Following Granny and other matriarch killer whales has shown their crucial role within the family group.
They guide the pod as it forages, take care of other females' young calves and even feed the larger males, researchers said.
These post-reproductive female leaders help their families to survive, and the advantage they offer could show what drives a species to evolve to stop reproducing.
"It was inevitable that this day was going to come but it is very sad news and a further blow to this population," said Darren Croft from the University of Exeter in the UK, who leads this evolutionary biology research.

In her later years she had "been helping her family group to survive by sharing her knowledge of when and where to find food," said Croft.

The orcas of an area known as the Salish Sea - close to Vancouver and Seattle - have been the subject of a four decades long study led by Ken Balcomb from the Center for Whale Research (CWR). He had first photographed Granny, official named J2, in 1976, 'BBC News' reported.
On the centre's website, which first reported Granny's death, Balcomb wrote that he last saw her on October 12 last year as she swam north far ahead of the others.

"Perhaps other dedicated whale-watchers have seen her since then, but by year's end she is officially missing from the Southern Resident Killer Whale population, and with regret we now consider her deceased," he said.