WEBVTT 00:00:12.071 --> 00:00:16.040 Sunning themselves on rocks or waddling awkwardly across the beach, 00:00:16.040 --> 00:00:20.031 it’s easy to think of these immobile mammals less as sea lions, 00:00:20.031 --> 00:00:22.478 and more as sea house cats. 00:00:22.478 --> 00:00:25.002 But don’t be fooled by their beachside behavior. 00:00:25.002 --> 00:00:29.284 Under the waves, sea lions are incredible endurance hunters. 00:00:29.284 --> 00:00:32.840 Hurtling around at speeds from 4 to 18 miles an hour 00:00:32.840 --> 00:00:35.706 and hunting for up to 30 hours at a time, 00:00:35.706 --> 00:00:39.011 these majestic mammals live up to their name. 00:00:39.011 --> 00:00:41.963 And thanks to a suite of physical adaptations, 00:00:41.963 --> 00:00:47.235 finely tuned over millions of years, they make for resourceful foragers. NOTE Paragraph 00:00:47.235 --> 00:00:48.900 To find their favorite food, 00:00:48.900 --> 00:00:53.542 sea lions hunt much deeper than many of their semi-aquatic peers. 00:00:53.542 --> 00:00:57.000 With some species diving to depths of nearly 400 meters, 00:00:57.000 --> 00:00:59.307 they’re able to cope with the mounting pressure 00:00:59.307 --> 00:01:04.379 by collapsing their pliable rib cage, and compressing a pair of springy lungs. 00:01:04.379 --> 00:01:07.151 This pushes air up through the smaller airways, 00:01:07.151 --> 00:01:11.298 collapsing rings of cartilage as oxygen travels out from the lungs, 00:01:11.298 --> 00:01:14.296 to be held in the larger, upper airways. 00:01:14.296 --> 00:01:18.514 Upon surfacing, this air will be used to re-inflate the lungs, 00:01:18.514 --> 00:01:22.825 but for now their heart slows down to preserve oxygen. 00:01:22.825 --> 00:01:26.657 Blood flow is redirected towards only the most essential organs 00:01:26.657 --> 00:01:29.109 like the heart, lungs, and brain, 00:01:29.109 --> 00:01:33.316 which rely on reserve oxygen stored in blood and muscle. NOTE Paragraph 00:01:33.316 --> 00:01:35.424 Once they arrive at their hunting ground, 00:01:35.424 --> 00:01:39.649 sea lions depend on their superior vision to find their prey. 00:01:39.649 --> 00:01:42.531 Most mammal eyes have a structure called a lens– 00:01:42.531 --> 00:01:47.351 a transparent, convex structure whose shape refracts light to enable sight. 00:01:47.351 --> 00:01:52.295 In humans, this lens is curved to process light waves traveling through air. 00:01:52.295 --> 00:01:56.833 But sea lions need to see their best at hundreds of meters deep. 00:01:56.833 --> 00:02:01.773 To accommodate, their eyes have a much rounder lens to refract light underwater, 00:02:01.773 --> 00:02:03.851 as well as teardrop-shaped pupils 00:02:03.851 --> 00:02:07.380 which can expand to 25 times their original size. 00:02:07.380 --> 00:02:09.593 This lets in as much light as possible, 00:02:09.593 --> 00:02:14.330 helping them pinpoint their prey in even the dimmest conditions. NOTE Paragraph 00:02:14.330 --> 00:02:15.892 But once they’ve closed in, 00:02:15.892 --> 00:02:21.352 they rely on something akin to a sixth sense to actually catch their meal. 00:02:21.352 --> 00:02:24.003 Their whiskers, or vibrissae, 00:02:24.003 --> 00:02:27.202 are composed of keratin and full of nerve fibers 00:02:27.202 --> 00:02:31.223 that run deep into the connective tissue of their face. 00:02:31.223 --> 00:02:34.956 Sea lions have full directional control over these whiskers, 00:02:34.956 --> 00:02:39.509 which can lie flat against their face, or stick out at a 90-degree angle. 00:02:39.509 --> 00:02:40.812 When properly tuned, 00:02:40.812 --> 00:02:45.792 these whiskers can sense the slim trails of moving water fish leave in their wake. 00:02:45.792 --> 00:02:49.128 And they’re precise enough to let blindfolded sea lions 00:02:49.128 --> 00:02:54.318 tell the difference between objects less than two centimeters different in size. NOTE Paragraph 00:02:54.318 --> 00:02:58.525 With these tools a healthy sea lion can catch generous helpings of fish 00:02:58.525 --> 00:03:02.476 such as anchovy, mackerel, and squid on every outing. 00:03:02.476 --> 00:03:06.363 And with their exceptional memories, they can remember multiple hunting grounds, 00:03:06.363 --> 00:03:09.143 including those they haven’t visited in decades. 00:03:09.143 --> 00:03:13.307 This memory also extends to breeding territories and birthing areas, 00:03:13.307 --> 00:03:16.787 as well as which neighbors are friend and foe. 00:03:16.787 --> 00:03:20.779 There’s even evidence that sea lions can remember how to perform tasks 00:03:20.779 --> 00:03:24.220 after 10 years with no practice in between, 00:03:24.220 --> 00:03:27.972 letting them navigate old stomping grounds with ease. NOTE Paragraph 00:03:27.972 --> 00:03:30.379 Yet despite these incredible adaptations, 00:03:30.379 --> 00:03:32.966 there are changes unfolding in their habitats 00:03:32.966 --> 00:03:35.799 too rapidly for sea lions to handle. 00:03:35.799 --> 00:03:40.944 As climate change warms the oceans, certain toxic algae species thrive. 00:03:40.944 --> 00:03:43.804 This algae is harmless to the fish who eat it, 00:03:43.804 --> 00:03:46.235 but for the sea lions which ingest those fish, 00:03:46.235 --> 00:03:50.517 the algae’s domoic acid can trigger seizures and brain damage. 00:03:50.517 --> 00:03:53.918 Changing ocean conditions keep this algae blooming year round, 00:03:53.918 --> 00:03:58.364 causing more and more sea lions to wash up on beaches. NOTE Paragraph 00:03:58.364 --> 00:04:01.322 This tragic discovery is just one of the many ways 00:04:01.322 --> 00:04:04.089 the health of aquatic animal communities can help us 00:04:04.089 --> 00:04:06.529 better understand Earth’s oceans. 00:04:06.529 --> 00:04:08.680 These red flags help us take action 00:04:08.680 --> 00:04:11.800 to protect ourselves and other maritime mammals. 00:04:11.800 --> 00:04:15.564 And the more we can learn about the changing ocean that sea lions inhabit, 00:04:15.564 --> 00:04:20.264 the better equipped we’ll be to help these clever creatures thrive.