1
00:00:12,071 --> 00:00:16,040
Sunning themselves on rocks or waddling 
awkwardly across the beach,

2
00:00:16,040 --> 00:00:20,031
it’s easy to think of these immobile 
mammals less as sea lions,

3
00:00:20,031 --> 00:00:22,478
and more as sea house cats.

4
00:00:22,478 --> 00:00:25,002
But don’t be fooled by their 
beachside behavior.

5
00:00:25,002 --> 00:00:29,284
Under the waves, sea lions are 
incredible endurance hunters.

6
00:00:29,284 --> 00:00:32,840
Hurtling around at speeds from 
4 to 18 miles an hour

7
00:00:32,840 --> 00:00:35,706
and hunting for up to 30 hours at a time,

8
00:00:35,706 --> 00:00:39,011
these majestic mammals live 
up to their name.

9
00:00:39,011 --> 00:00:41,963
And thanks to a suite of 
physical adaptations,

10
00:00:41,963 --> 00:00:47,235
finely tuned over millions of years, 
they make for resourceful foragers.

11
00:00:47,235 --> 00:00:48,900
To find their favorite food,

12
00:00:48,900 --> 00:00:53,542
sea lions hunt much deeper than 
many of their semi-aquatic peers.

13
00:00:53,542 --> 00:00:57,000
With some species diving to 
depths of nearly 400 meters,

14
00:00:57,000 --> 00:00:59,307
they’re able to cope with 
the mounting pressure

15
00:00:59,307 --> 00:01:04,379
by collapsing their pliable rib cage, 
and compressing a pair of springy lungs.

16
00:01:04,379 --> 00:01:07,151
This pushes air up through 
the smaller airways,

17
00:01:07,151 --> 00:01:11,298
collapsing rings of cartilage as 
oxygen travels out from the lungs,

18
00:01:11,298 --> 00:01:14,296
to be held in the larger, upper airways.

19
00:01:14,296 --> 00:01:18,514
Upon surfacing, this air will be 
used to re-inflate the lungs,

20
00:01:18,514 --> 00:01:22,825
but for now their heart slows 
down to preserve oxygen.

21
00:01:22,825 --> 00:01:26,657
Blood flow is redirected towards 
only the most essential organs

22
00:01:26,657 --> 00:01:29,109
like the heart, lungs, and brain,

23
00:01:29,109 --> 00:01:33,316
which rely on reserve oxygen 
stored in blood and muscle.

24
00:01:33,316 --> 00:01:35,424
Once they arrive at their hunting ground,

25
00:01:35,424 --> 00:01:39,649
sea lions depend on their superior 
vision to find their prey.

26
00:01:39,649 --> 00:01:42,531
Most mammal eyes have 
a structure called a lens–

27
00:01:42,531 --> 00:01:47,351
a transparent, convex structure whose 
shape refracts light to enable sight.

28
00:01:47,351 --> 00:01:52,295
In humans, this lens is curved to process 
light waves traveling through air.

29
00:01:52,295 --> 00:01:56,833
But sea lions need to see their 
best at hundreds of meters deep.

30
00:01:56,833 --> 00:02:01,773
To accommodate, their eyes have a much 
rounder lens to refract light underwater,

31
00:02:01,773 --> 00:02:03,851
as well as teardrop-shaped pupils

32
00:02:03,851 --> 00:02:07,380
which can expand to 25 times 
their original size.

33
00:02:07,380 --> 00:02:09,593
This lets in as much light as possible,

34
00:02:09,593 --> 00:02:14,330
helping them pinpoint their prey in 
even the dimmest conditions.

35
00:02:14,330 --> 00:02:15,892
But once they’ve closed in,

36
00:02:15,892 --> 00:02:21,352
they rely on something akin to a sixth 
sense to actually catch their meal.

37
00:02:21,352 --> 00:02:24,003
Their whiskers, or vibrissae,

38
00:02:24,003 --> 00:02:27,202
are composed of keratin 
and full of nerve fibers

39
00:02:27,202 --> 00:02:31,223
that run deep into the connective 
tissue of their face.

40
00:02:31,223 --> 00:02:34,956
Sea lions have full directional control 
over these whiskers,

41
00:02:34,956 --> 00:02:39,509
which can lie flat against their face, 
or stick out at a 90-degree angle.

42
00:02:39,509 --> 00:02:40,812
When properly tuned,

43
00:02:40,812 --> 00:02:45,792
these whiskers can sense the slim trails 
of moving water fish leave in their wake.

44
00:02:45,792 --> 00:02:49,128
And they’re precise enough to let 
blindfolded sea lions

45
00:02:49,128 --> 00:02:54,318
tell the difference between objects less 
than two centimeters different in size.

46
00:02:54,318 --> 00:02:58,525
With these tools a healthy sea lion can
catch generous helpings of fish

47
00:02:58,525 --> 00:03:02,476
such as anchovy, mackerel, 
and squid on every outing.

48
00:03:02,476 --> 00:03:06,363
And with their exceptional memories, they 
can remember multiple hunting grounds,

49
00:03:06,363 --> 00:03:09,143
including those they haven’t 
visited in decades.

50
00:03:09,143 --> 00:03:13,307
This memory also extends to breeding 
territories and birthing areas,

51
00:03:13,307 --> 00:03:16,787
as well as which neighbors 
are friend and foe.

52
00:03:16,787 --> 00:03:20,779
There’s even evidence that sea lions 
can remember how to perform tasks

53
00:03:20,779 --> 00:03:24,220
after 10 years with no 
practice in between,

54
00:03:24,220 --> 00:03:27,972
letting them navigate old stomping 
grounds with ease.

55
00:03:27,972 --> 00:03:30,379
Yet despite these incredible adaptations,

56
00:03:30,379 --> 00:03:32,966
there are changes unfolding 
in their habitats

57
00:03:32,966 --> 00:03:35,799
too rapidly for sea lions to handle.

58
00:03:35,799 --> 00:03:40,944
As climate change warms the oceans, 
certain toxic algae species thrive.

59
00:03:40,944 --> 00:03:43,804
This algae is harmless to 
the fish who eat it,

60
00:03:43,804 --> 00:03:46,235
but for the sea lions which 
ingest those fish,

61
00:03:46,235 --> 00:03:50,517
the algae’s domoic acid can trigger 
seizures and brain damage.

62
00:03:50,517 --> 00:03:53,918
Changing ocean conditions keep 
this algae blooming year round,

63
00:03:53,918 --> 00:03:58,364
causing more and more sea lions 
to wash up on beaches.

64
00:03:58,364 --> 00:04:01,322
This tragic discovery is just one 
of the many ways

65
00:04:01,322 --> 00:04:04,089
the health of aquatic animal 
communities can help us

66
00:04:04,089 --> 00:04:06,529
better understand Earth’s oceans.

67
00:04:06,529 --> 00:04:08,680
These red flags help us take action

68
00:04:08,680 --> 00:04:11,800
to protect ourselves and other 
maritime mammals.

69
00:04:11,800 --> 00:04:15,564
And the more we can learn about the 
changing ocean that sea lions inhabit,

70
00:04:15,564 --> 00:04:20,264
the better equipped we’ll be to help 
these clever creatures thrive.