1 00:00:06,739 --> 00:00:08,217 "Hi, Bob." 2 00:00:08,217 --> 00:00:11,219 "Morning, Kelly. The tulips looks great." 3 00:00:11,237 --> 00:00:14,966 Have you ever wondered how your dog experiences the world? 4 00:00:14,966 --> 00:00:16,581 Here's what she sees. 5 00:00:16,581 --> 00:00:18,696 Not terribly interesting. 6 00:00:18,696 --> 00:00:21,753 But what she smells, that's a totally different story. 7 00:00:22,266 --> 00:00:25,381 And it begins at her wonderfully developed nose. 8 00:00:25,381 --> 00:00:28,400 As your dog catches the first hints of fresh air, 9 00:00:28,004 --> 00:00:34,329 her nose's moist, spongy outside helps capture any scents the breeze carries. 10 00:00:34,725 --> 00:00:36,799 The ability to smell separately with each nostril, 11 00:00:37,465 --> 00:00:39,099 smelling in stereo, 12 00:00:39,099 --> 00:00:41,797 helps to determine the direction of the smell's source 13 00:00:41,797 --> 00:00:44,265 so that within the first few moments of sniffing, 14 00:00:44,265 --> 00:00:48,291 the dog starts to become aware of not just what kind of things are out there 15 00:00:48,291 --> 00:00:50,695 but also where they're located. 16 00:00:50,695 --> 00:00:52,303 As air enters the nose, 17 00:00:52,303 --> 00:00:56,101 a small fold of tissue divides it into two separate folds, 18 00:00:56,101 --> 00:00:59,106 one for breathing and one just for smelling. 19 00:00:59,151 --> 00:01:01,140 This second airflow enters a region 20 00:01:01,014 --> 00:01:04,297 filled with highly specialized olfactory receptor cells, 21 00:01:04,423 --> 00:01:08,534 several hundred millions of them, compaired to our five million. 22 00:01:08,534 --> 00:01:12,391 And unlike our clumsy way of breathing in and out through the same passage, 23 00:01:12,391 --> 00:01:15,313 dogs exhale through slits at the side of their nose, 24 00:01:15,313 --> 00:01:19,491 creating swirls of air that help draw in new odor molecules 25 00:01:19,491 --> 00:01:24,148 and allow odor concentration to build up over mulitple sniffs. 26 00:01:24,148 --> 00:01:27,716 But all that impressive nasal architecture wouldn't be much help 27 00:01:27,716 --> 00:01:32,562 without something to process the loads of information the nose scoops up. 28 00:01:32,562 --> 00:01:36,996 And it turns out that the olfactory system dedicated to proessing smells 29 00:01:36,996 --> 00:01:42,655 takes up many times more relative brain area in dogs than in humans. 30 00:01:42,655 --> 00:01:44,487 All of this allows dogs to distinguish 31 00:01:44,487 --> 00:01:48,155 and remember a staggering variety of specific scents 32 00:01:48,155 --> 00:01:53,416 at concentrations up to 100 million times less than what our noses can detect. 33 00:01:53,416 --> 00:01:56,082 If you can smell a spritz of perfume in a small room, 34 00:01:56,082 --> 00:01:59,780 a dog would have no trouble smelling it in an enclosed stadium 35 00:01:59,078 --> 00:02:01,840 and distinguishing its ingredients, to boot. 36 00:02:02,542 --> 00:02:05,768 And everything in the street, every passing person or car, 37 00:02:05,768 --> 00:02:08,060 any contents of the neighbor's trash, 38 00:02:08,006 --> 00:02:09,514 each type of tree, 39 00:02:09,568 --> 00:02:11,556 and all the birds and insects in it 40 00:02:11,556 --> 00:02:15,830 has a distinct odor profile telling your dog what it is, where it is, 41 00:02:15,083 --> 00:02:18,230 and which direction it's moving in. 42 00:02:18,977 --> 00:02:21,161 Besides being much more powerful than ours, 43 00:02:21,161 --> 00:02:26,042 a dog's sense of smell can pick up things that can't even be seen at all. 44 00:02:26,042 --> 00:02:27,967 A whole separate olfactory system, 45 00:02:27,967 --> 00:02:31,506 called the vomeronasal organ, above the roof of the mouth, 46 00:02:31,506 --> 00:02:36,033 detects the hormones all animals, Including humans, naturally release. 47 00:02:36,033 --> 00:02:38,310 It lets dogs identify potential mates, 48 00:02:38,031 --> 00:02:41,055 or distinguish between friendly and hostile animals. 49 00:02:41,055 --> 00:02:43,062 It alerts them to our various emotional states, 50 00:02:44,025 --> 00:02:48,171 and it can even tell them when someone is pregnant or sick. 51 00:02:48,396 --> 00:02:51,117 Because olfaction is more primal than other senses, 52 00:02:51,117 --> 00:02:54,400 bypassing the thalamus to connect directly to the brain structures 53 00:02:54,004 --> 00:02:56,597 involving emotion and instinct, 54 00:02:56,993 --> 00:03:01,625 we might even say a dog's perception is more immediate and visceral than ours. 55 00:03:01,625 --> 00:03:03,679 But the most amazing thing about your dog's nose 56 00:03:04,165 --> 00:03:06,343 is that it can traverse time. 57 00:03:06,343 --> 00:03:09,340 The past appears in tracks left by passersby, 58 00:03:09,034 --> 00:03:11,671 and by the warmth of a recently parked car 59 00:03:11,977 --> 00:03:16,068 where the residue of where you've been and what you've done recently. 60 00:03:16,887 --> 00:03:17,979 Landmarks like fire hydrants and trees 61 00:03:18,807 --> 00:03:21,884 are aromatic bulletin boards carrying messages of who's been by, 62 00:03:21,884 --> 00:03:23,330 what they've been eating, 63 00:03:23,033 --> 00:03:24,901 and how they're feeling. 64 00:03:25,198 --> 00:03:26,771 And the future is in the breeze, 65 00:03:26,771 --> 00:03:31,386 alerting them to something or someone approaching long before you see them. 66 00:03:31,386 --> 00:03:33,841 Where we see and hear something at a single moment, 67 00:03:33,841 --> 00:03:38,092 a dog smells an entire story from start to finish. 68 00:03:38,092 --> 00:03:41,075 In some of the best examples of canine-human collaboration, 69 00:03:41,075 --> 00:03:44,414 dogs help us by sharing and reacting to those stories. 70 00:03:44,414 --> 00:03:47,368 They can respond with kindness to people in distress, 71 00:03:47,368 --> 00:03:49,131 or with aggression to threats 72 00:03:49,131 --> 00:03:51,928 because stress and anger manifest as a cloud of hormones 73 00:03:51,928 --> 00:03:54,507 recognizable to the dog's nose. 74 00:03:54,507 --> 00:03:55,792 With the proper training, 75 00:03:55,792 --> 00:03:58,196 they can even alert us to invisible threats 76 00:03:58,196 --> 00:04:00,925 ranging from bombs to cancer. 77 00:04:00,925 --> 00:04:03,180 As it turns out, humanity's best friend 78 00:04:03,018 --> 00:04:06,366 is not one who experiences the same things we do, 79 00:04:06,528 --> 00:04:11,762 but one whose incredible nose reveals a whole other world beyond our eyes.