[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:30.91,0:00:32.72,Default,,0000,0000,0000,,Blue whales are the largest animals
Dialogue: 0,0:00:32.72,0:00:34.64,Default,,0000,0000,0000,,that have ever roamed the planet.
Dialogue: 0,0:00:34.64,0:00:37.78,Default,,0000,0000,0000,,They're at least two times as big as the biggest dinosaurs,
Dialogue: 0,0:00:38.95,0:00:40.28,Default,,0000,0000,0000,,"That's big!"
Dialogue: 0,0:00:40.28,0:00:41.74,Default,,0000,0000,0000,,the length of a basketball court,
Dialogue: 0,0:00:41.74,0:00:44.78,Default,,0000,0000,0000,,and as heavy as 40 African elephants.
Dialogue: 0,0:00:44.78,0:00:46.58,Default,,0000,0000,0000,,If that's not enough to make you marvel,
Dialogue: 0,0:00:46.58,0:00:48.66,Default,,0000,0000,0000,,here's something that will.
Dialogue: 0,0:00:48.66,0:00:50.37,Default,,0000,0000,0000,,They're grown to this enormous size
Dialogue: 0,0:00:50.37,0:00:54.70,Default,,0000,0000,0000,,by feeding exclusively on tiny shrimp-like creatures called krill
Dialogue: 0,0:00:58.33,0:01:00.57,Default,,0000,0000,0000,,that are no bigger than your little finger.
Dialogue: 0,0:01:00.57,0:01:02.56,Default,,0000,0000,0000,,In many ways, the sheer size of krill
Dialogue: 0,0:01:02.56,0:01:05.94,Default,,0000,0000,0000,,seems to have driven the evolution of the blue whale.
Dialogue: 0,0:01:08.03,0:01:10.09,Default,,0000,0000,0000,,See, krill are so small
Dialogue: 0,0:01:10.09,0:01:12.13,Default,,0000,0000,0000,,but are found in dense patches.
Dialogue: 0,0:01:12.13,0:01:13.13,Default,,0000,0000,0000,,For increased efficiency,
Dialogue: 0,0:01:13.13,0:01:14.47,Default,,0000,0000,0000,,blue whales have evolved
Dialogue: 0,0:01:14.47,0:01:15.72,Default,,0000,0000,0000,,to use a feeding strategy
Dialogue: 0,0:01:15.72,0:01:17.60,Default,,0000,0000,0000,,called lunge feeding.
Dialogue: 0,0:01:17.60,0:01:20.85,Default,,0000,0000,0000,,Basically, the whale accelerates towards a prey patch
Dialogue: 0,0:01:20.85,0:01:22.90,Default,,0000,0000,0000,,and opens its mouth wide.
Dialogue: 0,0:01:22.90,0:01:26.06,Default,,0000,0000,0000,,To increase the capacity, its mouth expands.
Dialogue: 0,0:01:26.06,0:01:28.18,Default,,0000,0000,0000,,The special, accordion-like blubber layer
Dialogue: 0,0:01:28.18,0:01:30.44,Default,,0000,0000,0000,,that extends from its snout to its belly button
Dialogue: 0,0:01:30.44,0:01:32.94,Default,,0000,0000,0000,,enables the whale to engulf large quantities
Dialogue: 0,0:01:32.94,0:01:35.18,Default,,0000,0000,0000,,of prey-laden water.
Dialogue: 0,0:01:42.84,0:01:44.38,Default,,0000,0000,0000,,With each giant gulp,
Dialogue: 0,0:01:44.38,0:01:48.13,Default,,0000,0000,0000,,the whale takes in 125% of its body weight
Dialogue: 0,0:01:48.13,0:01:50.30,Default,,0000,0000,0000,,in water and krill.
Dialogue: 0,0:01:50.30,0:01:51.97,Default,,0000,0000,0000,,The whale must then expel the water
Dialogue: 0,0:01:51.97,0:01:54.23,Default,,0000,0000,0000,,while retaining the yummy krill.
Dialogue: 0,0:01:54.23,0:01:56.45,Default,,0000,0000,0000,,To do this, it uses its baleen,
Dialogue: 0,0:01:56.45,0:01:58.27,Default,,0000,0000,0000,,the comb-like structure made of the same stuff
Dialogue: 0,0:01:58.27,0:02:00.88,Default,,0000,0000,0000,,our nails and hair are made of,
Dialogue: 0,0:02:00.88,0:02:02.62,Default,,0000,0000,0000,,and its tongue.
Dialogue: 0,0:02:08.60,0:02:10.91,Default,,0000,0000,0000,,It's pretty crazy that the blue whale's heart
Dialogue: 0,0:02:10.91,0:02:12.67,Default,,0000,0000,0000,,is as big as a small car,
Dialogue: 0,0:02:12.67,0:02:15.14,Default,,0000,0000,0000,,a child could crawl through its arteries,
Dialogue: 0,0:02:15.14,0:02:17.26,Default,,0000,0000,0000,,its tongue weighs as much as an elephant,
Dialogue: 0,0:02:17.26,0:02:20.05,Default,,0000,0000,0000,,but its esophagus is so small,
Dialogue: 0,0:02:20.05,0:02:23.26,Default,,0000,0000,0000,,the whale could choke on a loaf of bread.
Dialogue: 0,0:02:23.26,0:02:24.84,Default,,0000,0000,0000,,These whales are really not designed
Dialogue: 0,0:02:24.84,0:02:27.42,Default,,0000,0000,0000,,to feed on anything larger than krill.
Dialogue: 0,0:02:31.46,0:02:35.63,Default,,0000,0000,0000,,It's estimated that blue whales eat four tons of krill per day.
Dialogue: 0,0:02:35.63,0:02:36.89,Default,,0000,0000,0000,,Because of the incredible design,
Dialogue: 0,0:02:36.89,0:02:38.54,Default,,0000,0000,0000,,each dive provides the blue whale
Dialogue: 0,0:02:38.54,0:02:42.18,Default,,0000,0000,0000,,with 90 times as much energy as is used.
Dialogue: 0,0:02:42.18,0:02:46.94,Default,,0000,0000,0000,,Every mouthful of krill provides almost 480,000 calories,
Dialogue: 0,0:02:46.94,0:02:52.16,Default,,0000,0000,0000,,the same amount you get from eating 1,900 hamburgers.
Dialogue: 0,0:02:54.78,0:02:57.68,Default,,0000,0000,0000,,But, why are blue whales so big?
Dialogue: 0,0:02:57.68,0:02:59.19,Default,,0000,0000,0000,,Blue whales are considerably larger
Dialogue: 0,0:02:59.19,0:03:02.05,Default,,0000,0000,0000,,than the largest living land animal, the elephant.
Dialogue: 0,0:03:02.05,0:03:03.69,Default,,0000,0000,0000,,The heavier an animal is,
Dialogue: 0,0:03:03.69,0:03:06.20,Default,,0000,0000,0000,,the greater its relative surface area.
Dialogue: 0,0:03:06.20,0:03:07.52,Default,,0000,0000,0000,,As weight increases,
Dialogue: 0,0:03:07.52,0:03:09.68,Default,,0000,0000,0000,,there's a point at which the legs of that animal
Dialogue: 0,0:03:09.68,0:03:12.42,Default,,0000,0000,0000,,would simply collapse.
Dialogue: 0,0:03:12.42,0:03:14.26,Default,,0000,0000,0000,,That explains why elephants don't stand
Dialogue: 0,0:03:14.26,0:03:17.18,Default,,0000,0000,0000,,on the delicate legs of a horse.
Dialogue: 0,0:03:17.18,0:03:19.18,Default,,0000,0000,0000,,They need legs shaped like stout pedestals
Dialogue: 0,0:03:19.18,0:03:22.34,Default,,0000,0000,0000,,to hold their bodies up against gravity.
Dialogue: 0,0:03:25.23,0:03:28.03,Default,,0000,0000,0000,,In water, the situation is quite different.
Dialogue: 0,0:03:28.03,0:03:30.70,Default,,0000,0000,0000,,Buoyancy counteracts the gravitational pull on the body
Dialogue: 0,0:03:30.70,0:03:33.24,Default,,0000,0000,0000,,and their great bulk is therefore partially supported
Dialogue: 0,0:03:33.24,0:03:35.08,Default,,0000,0000,0000,,by the water.
Dialogue: 0,0:03:35.08,0:03:37.16,Default,,0000,0000,0000,,So, the ocean is a great place for species
Dialogue: 0,0:03:37.16,0:03:39.50,Default,,0000,0000,0000,,that want to grow bigger.
Dialogue: 0,0:03:39.50,0:03:42.33,Default,,0000,0000,0000,,The other secret to their size is their diet.
Dialogue: 0,0:03:42.33,0:03:44.04,Default,,0000,0000,0000,,By evolving such a huge mouth,
Dialogue: 0,0:03:44.04,0:03:46.64,Default,,0000,0000,0000,,the whale's have specialized to catch enormous quantities
Dialogue: 0,0:03:46.64,0:03:49.27,Default,,0000,0000,0000,,of highly abundant and nutritious prey,
Dialogue: 0,0:03:49.27,0:03:53.43,Default,,0000,0000,0000,,which provides the energy needed to grow so big.
Dialogue: 0,0:03:56.06,0:03:58.18,Default,,0000,0000,0000,,But, now maybe you're wondering
Dialogue: 0,0:03:58.18,0:04:00.77,Default,,0000,0000,0000,,why blue whales aren't any bigger?
Dialogue: 0,0:04:00.77,0:04:02.87,Default,,0000,0000,0000,,After all, the ocean sounds like nirvana
Dialogue: 0,0:04:02.87,0:04:04.45,Default,,0000,0000,0000,,for any growing beast.
Dialogue: 0,0:04:04.45,0:04:07.18,Default,,0000,0000,0000,,Well, while lunge feeding may have allowed blue whales
Dialogue: 0,0:04:07.18,0:04:08.64,Default,,0000,0000,0000,,to become the biggest animal
Dialogue: 0,0:04:08.64,0:04:10.34,Default,,0000,0000,0000,,to have ever roamed the planet,
Dialogue: 0,0:04:10.34,0:04:13.82,Default,,0000,0000,0000,,by enabling them to feed efficiently in dense prey patches,
Dialogue: 0,0:04:13.82,0:04:15.66,Default,,0000,0000,0000,,it isn't cost free.
Dialogue: 0,0:04:15.66,0:04:18.78,Default,,0000,0000,0000,,Scientists compared all the costs involved with lunge feeding
Dialogue: 0,0:04:18.78,0:04:21.46,Default,,0000,0000,0000,,to the energy gained from the krill they eat.
Dialogue: 0,0:04:21.46,0:04:24.83,Default,,0000,0000,0000,,What they found is that when the whale's body increases in size,
Dialogue: 0,0:04:24.83,0:04:27.38,Default,,0000,0000,0000,,the energy that body demands rises faster
Dialogue: 0,0:04:27.38,0:04:31.50,Default,,0000,0000,0000,,than the extra energy they get from their food.
Dialogue: 0,0:04:31.50,0:04:35.59,Default,,0000,0000,0000,,Feeding whales needs 15 times the energy required to remain still
Dialogue: 0,0:04:35.59,0:04:39.56,Default,,0000,0000,0000,,and 5 times more energy than used when swimming.
Dialogue: 0,0:04:39.56,0:04:40.96,Default,,0000,0000,0000,,Calculations show
Dialogue: 0,0:04:40.96,0:04:44.78,Default,,0000,0000,0000,,that the largest a lunge feeder can grow is 33 meters,
Dialogue: 0,0:04:44.78,0:04:47.31,Default,,0000,0000,0000,,pretty much blue whale size.
Dialogue: 0,0:04:47.31,0:04:49.78,Default,,0000,0000,0000,,Turns out blue whales have a lot to thank krill for:
Dialogue: 0,0:04:49.78,0:04:51.41,Default,,0000,0000,0000,,neat, evolutionary adaptations
Dialogue: 0,0:04:51.41,0:04:54.87,Default,,0000,0000,0000,,that would not have been possible if krill were not so small.
Dialogue: 0,0:04:54.87,0:04:56.92,Default,,0000,0000,0000,,It's incredible that these tiny creatures
Dialogue: 0,0:04:56.92,0:04:59.74,Default,,0000,0000,0000,,have allowed blue whales to really push the limits
Dialogue: 0,0:04:59.74,0:05:01.56,Default,,0000,0000,0000,,of size on our planet.
Dialogue: 0,0:05:01.56,0:05:03.67,Default,,0000,0000,0000,,Makes you wonder if that old adage,
Dialogue: 0,0:05:03.67,0:05:05.52,Default,,0000,0000,0000,,"You are what you eat,"
Dialogue: 0,0:05:05.52,0:05:09.13,Default,,0000,0000,0000,,really does apply in blue whale world.