[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:09.90,0:00:13.23,Default,,0000,0000,0000,,Off the rugged coast \Nof the pacific northwest,
Dialogue: 0,0:00:13.23,0:00:17.32,Default,,0000,0000,0000,,pods of killer whales \Ninhabit the frigid waters.
Dialogue: 0,0:00:17.32,0:00:19.54,Default,,0000,0000,0000,,Each family is able to survive here
Dialogue: 0,0:00:19.54,0:00:21.58,Default,,0000,0000,0000,,thanks mainly to one member,
Dialogue: 0,0:00:21.58,0:00:23.60,Default,,0000,0000,0000,,its most knowledgeable hunter:
Dialogue: 0,0:00:23.60,0:00:25.21,Default,,0000,0000,0000,,the grandmother.
Dialogue: 0,0:00:25.21,0:00:28.42,Default,,0000,0000,0000,,These matriarchs can live eighty years \Nor more,
Dialogue: 0,0:00:28.42,0:00:31.51,Default,,0000,0000,0000,,while most males die off \Nin their thirties.
Dialogue: 0,0:00:31.51,0:00:34.61,Default,,0000,0000,0000,,Though killer whales inhabit \Nevery major ocean,
Dialogue: 0,0:00:34.61,0:00:37.66,Default,,0000,0000,0000,,until recently we knew \Nvery little about them.
Dialogue: 0,0:00:37.66,0:00:40.52,Default,,0000,0000,0000,,The details of their lives \Neluded scientists
Dialogue: 0,0:00:40.52,0:00:44.03,Default,,0000,0000,0000,,until an organization called \Nthe Center for Whale Research
Dialogue: 0,0:00:44.03,0:00:46.61,Default,,0000,0000,0000,,began studying a single population
Dialogue: 0,0:00:46.61,0:00:51.38,Default,,0000,0000,0000,,near Washington State and \NBritish Columbia in 1976.
Dialogue: 0,0:00:51.38,0:00:52.98,Default,,0000,0000,0000,,Thanks to their ongoing work,
Dialogue: 0,0:00:52.98,0:00:55.37,Default,,0000,0000,0000,,we’ve learned a great deal \Nabout these whales,
Dialogue: 0,0:00:55.37,0:00:57.77,Default,,0000,0000,0000,,known as the Southern Residents.
Dialogue: 0,0:00:57.77,0:00:59.01,Default,,0000,0000,0000,,And the more we learn,
Dialogue: 0,0:00:59.01,0:01:04.39,Default,,0000,0000,0000,,the more this population’s elders’ \Nvital role comes into focus.
Dialogue: 0,0:01:04.39,0:01:07.07,Default,,0000,0000,0000,,Each grandmother starts her life as a calf
Dialogue: 0,0:01:07.07,0:01:10.88,Default,,0000,0000,0000,,born into her mother’s family group, \Nor matriline.
Dialogue: 0,0:01:10.88,0:01:12.94,Default,,0000,0000,0000,,The family does everything together,
Dialogue: 0,0:01:12.94,0:01:18.20,Default,,0000,0000,0000,,hunting and playing, even communicating \Nthrough their own unique set of calls.
Dialogue: 0,0:01:18.20,0:01:23.92,Default,,0000,0000,0000,,Both sons and daughters spend their entire\Nlives with their mothers’ families.
Dialogue: 0,0:01:23.92,0:01:28.15,Default,,0000,0000,0000,,That doesn’t mean a young whale \Nonly interacts with her relatives.
Dialogue: 0,0:01:28.15,0:01:30.38,Default,,0000,0000,0000,,Besides their own special calls,
Dialogue: 0,0:01:30.38,0:01:33.91,Default,,0000,0000,0000,,her matriline shares a dialect \Nwith nearby families,
Dialogue: 0,0:01:33.91,0:01:35.99,Default,,0000,0000,0000,,and they socialize regularly.
Dialogue: 0,0:01:35.99,0:01:39.08,Default,,0000,0000,0000,,Once a female reaches age fifteen or so,
Dialogue: 0,0:01:39.08,0:01:43.51,Default,,0000,0000,0000,,these meetings become opportunities \Nto mate with males from other groups.
Dialogue: 0,0:01:43.51,0:01:46.43,Default,,0000,0000,0000,,The relationships don’t go much \Nbeyond mating—
Dialogue: 0,0:01:46.43,0:01:49.03,Default,,0000,0000,0000,,she and her calves stay with her family,
Dialogue: 0,0:01:49.03,0:01:52.02,Default,,0000,0000,0000,,while the male returns to his own mother.
Dialogue: 0,0:01:52.02,0:01:54.28,Default,,0000,0000,0000,,Until approximately age forty,
Dialogue: 0,0:01:54.28,0:01:57.82,Default,,0000,0000,0000,,she gives birth every 6 years on average.
Dialogue: 0,0:01:57.82,0:02:00.29,Default,,0000,0000,0000,,Then, she goes through menopause—
Dialogue: 0,0:02:00.29,0:02:03.62,Default,,0000,0000,0000,,which is almost unheard of \Nin the animal kingdom.
Dialogue: 0,0:02:03.62,0:02:07.24,Default,,0000,0000,0000,,In fact, humans, killer whales and \Na few other whales
Dialogue: 0,0:02:07.24,0:02:11.23,Default,,0000,0000,0000,,are the only species whose females \Ncontinue to live for years
Dialogue: 0,0:02:11.23,0:02:14.00,Default,,0000,0000,0000,,after they stop reproducing.
Dialogue: 0,0:02:14.00,0:02:15.23,Default,,0000,0000,0000,,After menopause,
Dialogue: 0,0:02:15.23,0:02:18.45,Default,,0000,0000,0000,,grandmothers take the lead \Nhunting for salmon,
Dialogue: 0,0:02:18.45,0:02:21.11,Default,,0000,0000,0000,,the Southern Residents’ main food source.
Dialogue: 0,0:02:21.11,0:02:23.62,Default,,0000,0000,0000,,Most of the winter they forage offshore,
Dialogue: 0,0:02:23.62,0:02:26.09,Default,,0000,0000,0000,,supplementing salmon with other fish.
Dialogue: 0,0:02:26.09,0:02:30.31,Default,,0000,0000,0000,,But when the salmon head \Ntowards shore in droves to spawn,
Dialogue: 0,0:02:30.31,0:02:32.61,Default,,0000,0000,0000,,the killer whales follow.
Dialogue: 0,0:02:32.61,0:02:34.75,Default,,0000,0000,0000,,The matriarch shows the younger whales
Dialogue: 0,0:02:34.75,0:02:37.88,Default,,0000,0000,0000,,where to find the most fertile \Nfishing grounds.
Dialogue: 0,0:02:37.88,0:02:42.77,Default,,0000,0000,0000,,She also shares up to 90% of \Nthe salmon she catches.
Dialogue: 0,0:02:42.77,0:02:44.24,Default,,0000,0000,0000,,With each passing year,
Dialogue: 0,0:02:44.24,0:02:46.79,Default,,0000,0000,0000,,her contributions become more vital:
Dialogue: 0,0:02:46.79,0:02:51.87,Default,,0000,0000,0000,,overfishing and habitat destruction have \Ndecimated salmon populations,
Dialogue: 0,0:02:51.87,0:02:56.15,Default,,0000,0000,0000,,putting the whales at near-constant \Nrisk of starvation.
Dialogue: 0,0:02:56.16,0:02:58.01,Default,,0000,0000,0000,,These grandmothers’ expertise
Dialogue: 0,0:02:58.01,0:03:01.91,Default,,0000,0000,0000,,can mean the difference between \Nlife and death for their families–
Dialogue: 0,0:03:01.91,0:03:04.20,Default,,0000,0000,0000,,but why do they stop having calves?
Dialogue: 0,0:03:04.20,0:03:08.66,Default,,0000,0000,0000,,It’s almost always advantageous for a\Nfemale to continue reproducing,
Dialogue: 0,0:03:08.66,0:03:12.79,Default,,0000,0000,0000,,even if she also cares for her existing \Nchildren and grandchildren.
Dialogue: 0,0:03:12.79,0:03:17.41,Default,,0000,0000,0000,,A couple unique circumstances \Nchange this equation for killer whales.
Dialogue: 0,0:03:17.41,0:03:20.42,Default,,0000,0000,0000,,The fact that neither sons or daughters
Dialogue: 0,0:03:20.42,0:03:23.64,Default,,0000,0000,0000,,leave their families of origin \Nis extremely rare—
Dialogue: 0,0:03:23.64,0:03:26.04,Default,,0000,0000,0000,,in almost all animal species,
Dialogue: 0,0:03:26.04,0:03:28.79,Default,,0000,0000,0000,,one or both sexes disperse.
Dialogue: 0,0:03:28.79,0:03:31.93,Default,,0000,0000,0000,,This means that as a female \Nkiller whale ages,
Dialogue: 0,0:03:31.93,0:03:33.89,Default,,0000,0000,0000,,a greater percentage of her family
Dialogue: 0,0:03:33.89,0:03:36.60,Default,,0000,0000,0000,,consists of her children \Nand grandchildren,
Dialogue: 0,0:03:36.60,0:03:39.42,Default,,0000,0000,0000,,while more distant relatives die off.
Dialogue: 0,0:03:39.42,0:03:44.13,Default,,0000,0000,0000,,Because older females are more closely \Nrelated to the group than younger females,
Dialogue: 0,0:03:44.13,0:03:47.51,Default,,0000,0000,0000,,they do best to invest in the family \Nas a whole,
Dialogue: 0,0:03:47.51,0:03:51.23,Default,,0000,0000,0000,,whereas younger females should \Ninvest in reproducing.
Dialogue: 0,0:03:51.23,0:03:52.91,Default,,0000,0000,0000,,In the killer whale’s environment,
Dialogue: 0,0:03:52.91,0:03:55.59,Default,,0000,0000,0000,,every new calf is another mouth to feed
Dialogue: 0,0:03:55.59,0:03:58.30,Default,,0000,0000,0000,,on limited, shared resources.
Dialogue: 0,0:03:58.30,0:04:02.58,Default,,0000,0000,0000,,An older female can further her genes\Nwithout burdening her family
Dialogue: 0,0:04:02.58,0:04:04.76,Default,,0000,0000,0000,,by supporting her adult sons,
Dialogue: 0,0:04:04.76,0:04:07.80,Default,,0000,0000,0000,,who sire calves other families will raise.
Dialogue: 0,0:04:07.80,0:04:10.23,Default,,0000,0000,0000,,This might be why the females have evolved
Dialogue: 0,0:04:10.23,0:04:14.32,Default,,0000,0000,0000,,to stop reproducing entirely \Nin middle age.
Dialogue: 0,0:04:14.32,0:04:16.80,Default,,0000,0000,0000,,Even with the grandmothers’ contributions,
Dialogue: 0,0:04:16.80,0:04:20.20,Default,,0000,0000,0000,,the Southern Resident killer whales \Nare critically endangered,
Dialogue: 0,0:04:20.20,0:04:23.05,Default,,0000,0000,0000,,largely due to a decline in salmon.
Dialogue: 0,0:04:23.05,0:04:26.56,Default,,0000,0000,0000,,We urgently need to invest in restoring \Nsalmon populations
Dialogue: 0,0:04:26.56,0:04:28.44,Default,,0000,0000,0000,,to save them from extinction.
Dialogue: 0,0:04:28.44,0:04:32.74,Default,,0000,0000,0000,,In the long term, we’ll need more studies \Nlike the Center for Whale Research’s.
Dialogue: 0,0:04:32.74,0:04:34.98,Default,,0000,0000,0000,,What we’ve learned about \Nthe Southern Residents
Dialogue: 0,0:04:34.98,0:04:37.17,Default,,0000,0000,0000,,may not hold true for other groups.
Dialogue: 0,0:04:37.17,0:04:39.61,Default,,0000,0000,0000,,By studying other populations closely,
Dialogue: 0,0:04:39.61,0:04:42.60,Default,,0000,0000,0000,,we might uncover more \Nstartling adaptations,
Dialogue: 0,0:04:42.20,0:04:46.16,Default,,0000,0000,0000,,and anticipate their vulnerabilities \Nto human interference
Dialogue: 0,0:04:46.16,0:04:49.31,Default,,0000,0000,0000,,before their survival is at risk.