0:00:12.071,0:00:16.040
Sunning themselves on rocks or waddling [br]awkwardly across the beach,

0:00:16.040,0:00:20.031
it’s easy to think of these immobile [br]mammals less as sea lions,

0:00:20.031,0:00:22.478
and more as sea house cats.

0:00:22.478,0:00:25.002
But don’t be fooled by their [br]beachside behavior.

0:00:25.002,0:00:29.284
Under the waves, sea lions are [br]incredible endurance hunters.

0:00:29.284,0:00:32.840
Hurtling around at speeds from [br]4 to 18 miles an hour

0:00:32.840,0:00:35.706
and hunting for up to 30 hours at a time,

0:00:35.706,0:00:39.011
these majestic mammals live [br]up to their name.

0:00:39.011,0:00:41.963
And thanks to a suite of [br]physical adaptations,

0:00:41.963,0:00:47.235
finely tuned over millions of years, [br]they make for resourceful foragers.

0:00:47.235,0:00:48.900
To find their favorite food,

0:00:48.900,0:00:53.542
sea lions hunt much deeper than [br]many of their semi-aquatic peers.

0:00:53.542,0:00:57.000
With some species diving to [br]depths of nearly 400 meters,

0:00:57.000,0:00:59.307
they’re able to cope with [br]the mounting pressure

0:00:59.307,0:01:04.379
by collapsing their pliable rib cage, [br]and compressing a pair of springy lungs.

0:01:04.379,0:01:07.151
This pushes air up through [br]the smaller airways,

0:01:07.151,0:01:11.298
collapsing rings of cartilage as [br]oxygen travels out from the lungs,

0:01:11.298,0:01:14.296
to be held in the larger, upper airways.

0:01:14.296,0:01:18.514
Upon surfacing, this air will be [br]used to re-inflate the lungs,

0:01:18.514,0:01:22.825
but for now their heart slows [br]down to preserve oxygen.

0:01:22.825,0:01:26.657
Blood flow is redirected towards [br]only the most essential organs

0:01:26.657,0:01:29.109
like the heart, lungs, and brain,

0:01:29.109,0:01:33.316
which rely on reserve oxygen [br]stored in blood and muscle.

0:01:33.316,0:01:35.424
Once they arrive at their hunting ground,

0:01:35.424,0:01:39.649
sea lions depend on their superior [br]vision to find their prey.

0:01:39.649,0:01:42.531
Most mammal eyes have [br]a structure called a lens–

0:01:42.531,0:01:47.351
a transparent, convex structure whose [br]shape refracts light to enable sight.

0:01:47.351,0:01:52.295
In humans, this lens is curved to process [br]light waves traveling through air.

0:01:52.295,0:01:56.833
But sea lions need to see their [br]best at hundreds of meters deep.

0:01:56.833,0:02:01.773
To accommodate, their eyes have a much [br]rounder lens to refract light underwater,

0:02:01.773,0:02:03.851
as well as teardrop-shaped pupils

0:02:03.851,0:02:07.380
which can expand to 25 times [br]their original size.

0:02:07.380,0:02:09.593
This lets in as much light as possible,

0:02:09.593,0:02:14.330
helping them pinpoint their prey in [br]even the dimmest conditions.

0:02:14.330,0:02:15.892
But once they’ve closed in,

0:02:15.892,0:02:21.352
they rely on something akin to a sixth [br]sense to actually catch their meal.

0:02:21.352,0:02:24.003
Their whiskers, or vibrissae,

0:02:24.003,0:02:27.202
are composed of keratin [br]and full of nerve fibers

0:02:27.202,0:02:31.223
that run deep into the connective [br]tissue of their face.

0:02:31.223,0:02:34.956
Sea lions have full directional control [br]over these whiskers,

0:02:34.956,0:02:39.509
which can lie flat against their face, [br]or stick out at a 90-degree angle.

0:02:39.509,0:02:40.812
When properly tuned,

0:02:40.812,0:02:45.792
these whiskers can sense the slim trails [br]of moving water fish leave in their wake.

0:02:45.792,0:02:49.128
And they’re precise enough to let [br]blindfolded sea lions

0:02:49.128,0:02:54.318
tell the difference between objects less [br]than two centimeters different in size.

0:02:54.318,0:02:58.525
With these tools a healthy sea lion can[br]catch generous helpings of fish

0:02:58.525,0:03:02.476
such as anchovy, mackerel, [br]and squid on every outing.

0:03:02.476,0:03:06.363
And with their exceptional memories, they [br]can remember multiple hunting grounds,

0:03:06.363,0:03:09.143
including those they haven’t [br]visited in decades.

0:03:09.143,0:03:13.307
This memory also extends to breeding [br]territories and birthing areas,

0:03:13.307,0:03:16.787
as well as which neighbors [br]are friend and foe.

0:03:16.787,0:03:20.779
There’s even evidence that sea lions [br]can remember how to perform tasks

0:03:20.779,0:03:24.220
after 10 years with no [br]practice in between,

0:03:24.220,0:03:27.972
letting them navigate old stomping [br]grounds with ease.

0:03:27.972,0:03:30.379
Yet despite these incredible adaptations,

0:03:30.379,0:03:32.966
there are changes unfolding [br]in their habitats

0:03:32.966,0:03:35.799
too rapidly for sea lions to handle.

0:03:35.799,0:03:40.944
As climate change warms the oceans, [br]certain toxic algae species thrive.

0:03:40.944,0:03:43.804
This algae is harmless to [br]the fish who eat it,

0:03:43.804,0:03:46.235
but for the sea lions which [br]ingest those fish,

0:03:46.235,0:03:50.517
the algae’s domoic acid can trigger [br]seizures and brain damage.

0:03:50.517,0:03:53.918
Changing ocean conditions keep [br]this algae blooming year round,

0:03:53.918,0:03:58.364
causing more and more sea lions [br]to wash up on beaches.

0:03:58.364,0:04:01.322
This tragic discovery is just one [br]of the many ways

0:04:01.322,0:04:04.089
the health of aquatic animal [br]communities can help us

0:04:04.089,0:04:06.529
better understand Earth’s oceans.

0:04:06.529,0:04:08.680
These red flags help us take action

0:04:08.680,0:04:11.800
to protect ourselves and other [br]maritime mammals.

0:04:11.800,0:04:15.564
And the more we can learn about the [br]changing ocean that sea lions inhabit,

0:04:15.564,0:04:20.264
the better equipped we’ll be to help [br]these clever creatures thrive.