1
00:00:01,920 --> 00:00:06,520
Speaker 1: Welcome to brain Stuff production of I Heart Radio, Hey

2
00:00:06,559 --> 00:00:12,000
Speaker 1: brain Stuff Lauren Vogelbaum. Here bats fly head first, belly

3
00:00:12,080 --> 00:00:14,920
Speaker 1: down and wings stretched out to the side, just as

4
00:00:15,000 --> 00:00:18,680
Speaker 1: you might expect. So how do they land upside down,

5
00:00:19,000 --> 00:00:25,280
Speaker 1: a position that requires the midair acrobatics of a circus flyer. Well,

6
00:00:25,320 --> 00:00:28,400
Speaker 1: before we answer that question, we first need to look

7
00:00:28,400 --> 00:00:30,920
Speaker 1: at why bats would even want to land upside down.

8
00:00:30,960 --> 00:00:34,120
Speaker 1: To begin with, no other flying animal lands this way.

9
00:00:34,360 --> 00:00:36,880
Speaker 1: Why not just land like birds do with their feet

10
00:00:36,960 --> 00:00:41,640
Speaker 1: firmly under their bodies. The short answer is because bats

11
00:00:41,680 --> 00:00:43,959
Speaker 1: wouldn't be strong enough to take off if they were

12
00:00:44,000 --> 00:00:47,519
Speaker 1: sitting up right. Their wings don't produce enough lift, and

13
00:00:47,560 --> 00:00:49,960
Speaker 1: their legs are too short to run along the ground

14
00:00:50,040 --> 00:00:52,160
Speaker 1: to generate enough speed to get them into the air

15
00:00:52,320 --> 00:00:56,520
Speaker 1: from a head above feet position. Instead, they climb up

16
00:00:56,600 --> 00:01:01,320
Speaker 1: high and literally fall into flying by landing and roosting

17
00:01:01,400 --> 00:01:04,560
Speaker 1: upside down. They're ready to take flight if something threatens

18
00:01:04,600 --> 00:01:09,680
Speaker 1: their sleep. So that's the why. But how do they

19
00:01:09,680 --> 00:01:12,600
Speaker 1: get into this position when they aren't flying very fast

20
00:01:12,640 --> 00:01:17,520
Speaker 1: and they can't cover upside down? It's all about inertia.

21
00:01:17,760 --> 00:01:21,240
Speaker 1: Inertia involves Newton's first law of motion, which says a

22
00:01:21,280 --> 00:01:24,040
Speaker 1: body at rest will stay at rest unless and outside

23
00:01:24,040 --> 00:01:26,720
Speaker 1: force acts on it, and a body and motion will

24
00:01:26,720 --> 00:01:30,080
Speaker 1: continue in a straight line unless acted upon by an

25
00:01:30,080 --> 00:01:34,679
Speaker 1: outside force. And here is where inertia comes in. Inertia

26
00:01:34,880 --> 00:01:37,840
Speaker 1: is proportional to a body's mass, which is the amount

27
00:01:37,840 --> 00:01:40,600
Speaker 1: of matter that a body has. The more mass, the

28
00:01:40,640 --> 00:01:44,800
Speaker 1: more inertia. But how does this relate to bats. Well,

29
00:01:44,920 --> 00:01:48,640
Speaker 1: they don't have much mass, they're small. And here's the thing.

30
00:01:49,360 --> 00:01:52,440
Speaker 1: Bat wings have a lot of mass relative to their

31
00:01:52,480 --> 00:01:55,680
Speaker 1: body size. Their wings have evolved to be made up

32
00:01:55,680 --> 00:01:58,960
Speaker 1: of solid bones and muscles and so are heavier than

33
00:01:59,000 --> 00:02:02,200
Speaker 1: the wings of most are flying critters, which would suggest

34
00:02:02,280 --> 00:02:04,279
Speaker 1: that it might be difficult to get off the ground,

35
00:02:04,800 --> 00:02:08,520
Speaker 1: and it is remember they fall into flight. However, that

36
00:02:08,760 --> 00:02:12,480
Speaker 1: same mass, when acted on by an outside force, such

37
00:02:12,520 --> 00:02:15,120
Speaker 1: as a tiny little movement of the muscles and the

38
00:02:15,120 --> 00:02:18,480
Speaker 1: wings while in motion, will serve to reorient the bat

39
00:02:18,720 --> 00:02:24,000
Speaker 1: and get it upside down. Researchers at the Brown University

40
00:02:24,040 --> 00:02:27,480
Speaker 1: Bat Lab, or as it's officially known, the Aerial Mechanics

41
00:02:27,520 --> 00:02:32,160
Speaker 1: and Evolutionary Morphology Lab A recently studied bat landings using

42
00:02:32,200 --> 00:02:35,960
Speaker 1: cameras to capture the movements of the bats. They discovered

43
00:02:36,040 --> 00:02:39,040
Speaker 1: that as bats got closer to the ceiling of their enclosure,

44
00:02:39,360 --> 00:02:42,200
Speaker 1: they pulled one wing in close to their bodies while

45
00:02:42,240 --> 00:02:45,919
Speaker 1: still flapping the other wing at full extension. This allowed

46
00:02:45,960 --> 00:02:48,600
Speaker 1: the bats to rotate to the right position to land

47
00:02:48,639 --> 00:02:52,120
Speaker 1: feet first on the ceiling. Think about paddling a rowboat

48
00:02:52,160 --> 00:02:54,680
Speaker 1: on just one side of the boat. It makes you

49
00:02:54,760 --> 00:02:59,600
Speaker 1: turn and bats aren't the only animals that exhibit inertial

50
00:02:59,720 --> 00:03:04,160
Speaker 1: re orientation, as the researchers call it. For the article

51
00:03:04,200 --> 00:03:06,480
Speaker 1: this episode is based on How Stuff Works. Spoke with

52
00:03:06,480 --> 00:03:11,200
Speaker 1: study author and principal investigator Sharon Swartz. She said this

53
00:03:11,280 --> 00:03:14,160
Speaker 1: kind of maneuvering is similar to the mechanism used by

54
00:03:14,280 --> 00:03:17,040
Speaker 1: cats to re orient to land on their feet, but

55
00:03:17,200 --> 00:03:20,440
Speaker 1: is also used in many other animals. Geckos move their

56
00:03:20,480 --> 00:03:23,760
Speaker 1: big tails in this way to stabilize themselves during climbing

57
00:03:23,800 --> 00:03:27,280
Speaker 1: and writing. Lemurs use this mechanism in their big jumps.

58
00:03:28,000 --> 00:03:30,919
Speaker 1: We humans employ the sort of movement when gymnasts or

59
00:03:31,000 --> 00:03:35,400
Speaker 1: springboard divers execute somersaults or twists, or when a figure

60
00:03:35,400 --> 00:03:38,200
Speaker 1: skater changes the speed of a spin by changing the

61
00:03:38,240 --> 00:03:43,800
Speaker 1: details of the position of arms or legs. And speaking

62
00:03:43,800 --> 00:03:47,160
Speaker 1: of humans, the United States Air Force helped fund this

63
00:03:47,240 --> 00:03:53,600
Speaker 1: study because sports said quote. Research into the aerodynamics, neural control, biomaterials,

64
00:03:53,680 --> 00:03:56,800
Speaker 1: et cetera of flying animals can give builders of small

65
00:03:56,880 --> 00:04:05,920
Speaker 1: aerial vehicles rich material for their design idea. Y Today's

66
00:04:05,920 --> 00:04:08,680
Speaker 1: episode is based on the article Scientists Solve the Weird

67
00:04:08,720 --> 00:04:11,280
Speaker 1: Physics of How bats land Upside Down on House to

68
00:04:11,360 --> 00:04:14,840
Speaker 1: farks dot Com, written by Karen Kirkpatrick. Brainstuff is production

69
00:04:14,880 --> 00:04:16,960
Speaker 1: of I Heart Radio in partnership with hous towarks dot

70
00:04:16,960 --> 00:04:19,919
Speaker 1: Com and is produced by Tyler Plain. Four more podcasts

71
00:04:20,000 --> 00:04:23,080
Speaker 1: my heart Radio visit the i heart Radio app, Apple Podcasts,

72
00:04:23,160 --> 00:04:24,920
Speaker 1: or wherever you listen to your favorite shows