Transcript:

[0:00]

We're going to start this podcast with using your imagination again. So just imagine a small band of horses in the American West, to the foothills of California. And under a large oak tree sits a male cougar. He’s seasoned — he's lived in the wild for a few years, knows what he can catch and what he can't catch. His golden coat blends in with the light soil, the shadows hiding him. And he hears something, and his ears prick up, and he sees a small band of wild horses grazing nearby, eating some of the dry scrub grass, getting whatever nutrients they can out of it. And he normally wouldn't bother — they're so tough to catch, they're too fast, too big for some of them. But he sees a young foal, maybe three months old. So he quietly rolls up on his haunches and stretches out his claws a little bit, and watches in interest. Could he? Maybe… he's probably thinking, “Hmm, that might be a nice meal.”

[1:10]

Now imagine the foal's mom. She's sniffing around, her nose is down near the ground, inhaling the plant's aroma. She can't see it, but she can feel it with her lips, her whiskers brushing past the long stalks. The smell’s right, so she takes a nibble. Tastes right — chews and swallows. In her peripheral vision she can see almost all around her, and she's always scanning for threats. Then suddenly — a crack. It's soft, but enough for her to hear the sound waves traveling. She catches it with her ear, and she turns her head, focuses her ears. Her brain's telling her to look in that direction of a possible threat, and she narrows her eyes. Now, the tree's a yellowish-gray hue… just maybe there's something there.

[2:09]

And she watches for a few minutes, swishing her tail. Then, as the wind shifts, she catches that pungent aroma — it's a predator. Instant alarm call. All the horses are up and they're gone in a split second, thundering down the hillside. Cougar lays back down, opportunity lost, but it's time to catch some sleep. That scenario plays out day in, day out, around the world for many of our wild equids. It's played out that way for millions of years. They have evolved to be survivors and to detect the slightest indication that there might be a predator nearby — and that is why they have survived this long. And this is how they do it.

[3:01]

[Archival horse racing and documentary audio:] “And Secretariat being led… he is number… the horse, and the horse is the best thing in the world, isn’t it? I've always loved them, really, ever since I was a little girl. Everybody’s in line… and there’s Secretariat away very well, has good position…” “The love — I never thought owning a horse could mean so much to me.” “Secretariat now taking the lead — the madness!” “What kind of a horse is that? I’ve never seen a horse like that before!” “…is tying now! He is moving like a tremendous machine!” “Their story — Mustangs are more involved in the early development of this breed than I thought they were…” “…but they were…” “Car has opened the 202—” “…he is going to be the Triple Crown…” “Welcome to Ma—”

[3:52]

[Music] Horses. In this episode, we're going to cover just the basic senses and how horses navigate their environment: sight, sound, smell, taste, and feel. How do they do this compared to, say, us — and how we navigate our own lives? It’s such an important aspect of understanding our equid companions. When you understand how they navigate their environments day in, day out, that plays a key role in how we handle them, how we train them, how we ride them, and how we take care of them. And it's so important to understand how they see the world, so then we can be a part of it — and still keep that tight companionship that we have with them.

[4:49]

Now, I opened up this podcast with just telling a brief scenario of what wild horses in the Americas might experience with cougars. Our zebras in Africa deal with this day in, day out, with some of the top predators — lions. Our wild donkeys deal with it. Our domestic animals deal with it — domestic horses in the Americas with bears and wolves in Canada, in the northern United States. In Asia, the plains have plenty of predators. So horses, as we've discussed their history in these many podcasts, these millions of years, have really sharpened their senses to survive.

[5:32]

And think about it — some of the most hostile environments on our planet: rain, sleet, snow. And then you go to the deserts — the high deserts, the low deserts. Our equids are true survivors, and they have optimized their bodies to survive against these terrifying predators — and also to find food, find water, water to raise their young, to form strong social bonds. All of this plays such a key role in understanding them. So that is why this is such an important podcast for any horse enthusiast, because it is so important to understand this, and it just rolls into so much more of their physiology and behavior. And I will just say — knowing their senses is knowing them. And that's the whole reason we're doing this podcast — to make the world better for the horses, and the donkeys, and the mules, and you. That is the entire point of this.

[6:41]

Going through this, trying to describe this in an audio podcast setting, it's going to take a little bit of your imagination. And again, that's why when I talk about the spoken word and how it has shaped who we are through our history, I think that's why podcasting is so big today — and will continue to be big for quite a long time. But using your imagination through this process, and imagining how the horses see the world — and we're going to start with sight.

[7:10]

It is really thought as one of the most important senses for the horse. And for anybody that's visually impaired out there — I was really thinking about this point in the podcast, and I have a lot of admiration for you. But when we do talk about our horses, sight is so important. Now, there are blind horses — I've worked with horses that have had one eye removed. It does impact their behavior, it does impact how you work around them. You have to be very careful, especially on their blind sides. And then I've seen one horse that was completely blind, and that was when I was visiting Michigan State many years ago. They had a horse that was very sensitive to sound, vibrations on the ground, and the veterinary school there was learning how to care for a blind horse. But for most horses in the world that do have their eyesight, it is so important.

[8:04]

And just to kind of talk about how eyes work — and how, you know, the horse's eyes particularly — but also us, and other… almost every species on Earth has eyesight. To give you the quick version on how eyes work, because it still blows me away — physiology — that’s why I've dedicated my life to studying physiology in animals, and particularly horses. The way the eyes work is they pick up patterns of light and it transfers these signals to the brain and turns them into images.

[8:50]

Now, just a quick step-by-step about how this might work, and especially how this works for a horse: light rays — let's say the sun — bounce off the grass, and then the horse's eyes pick up that light. The outer portion of the eye has the cornea — it's the window, and it helps focus the light to the pupil, which is the dark part of the horse's eye (dark part of our eyes). The color on the outside of the pupil — mine are brown, other people have blue, green — is the iris. Horses, their irises are usually brown, but we do have blue-eyed horses — seen plenty of those. But even some rare horses have hazel, green, or amber-colored eyes. They're beautiful — they're absolutely beautiful. And it's actually the rarest eye color in horses. They usually find them in pearl or cream-colored horses, but they're pretty uncommon.

[9:38]

Now, what the iris does is control the pupil. So in bright light, it narrows, and in low light, it widens. It takes a while for our lens to adjust — and it actually takes horses a little bit longer. When we talk about night vision, when they go from light to dark, it actually takes them quite much longer than it does for us. Behind the pupil is a lens, and that is what allows us and horses to see depth, far and close up. In the back of the eyeball is the retina, which in us is about 130 million tiny cells that convert these light signals to electrical signals to our brain.

[10:25]

So that's the quick description of the eyeball, and ophthalmologists and people who study this in veterinary medicine — you have eye specialists now. When I opened this podcast talking about the mountain lion, the cougar, predators — our eyes are set in front of our faces, where we have really good binocular vision. You know, if you think of a set of binoculars, we hold them up to our eyes and we can see great distances, we can magnify things. We have really good bino vision where we can really zoom in and read letters and things like that. Horses — they don't have great binocular vision, but they have really good monocular vision.

[11:05]

Okay, so if we imagine, as you're driving, as you're listening to this podcast — when you look out, you can probably, you know, put your arms out (if you're not driving, please), but if you can imagine putting your arms out, in your peripheral vision when you're looking straight ahead, there's a point where you can't see your hands anymore. And that's generally about 150 degrees. We have about a 150-degree view of the world. So we can use our binocular vision to focus in and see things, and then our peripheral vision.

[11:48]

Horses have a 350-degree view around them. So again, if you're not driving, you can put your hands all the way behind you, almost straight back, and there's only about 10 degrees behind you where a horse couldn't see — but they can see all of that view. Three hundred fifty out of 360 degrees, the horse has vision. Now, most of that vision is monocular. So, binocular — we see with two eyes. Monocular is just one eye. You can't really focus in on the fine details, but you can see out, or the horse can see out, behind them and to their sides and to their fronts with monocular vision, because their eyes are set laterally on the sides of their heads.

[12:46]

Cattle, sheep, zebras, gazelles, elephants — all of these large herbivores — their eyes are set to the sides of their faces, so they have really good monocular vision and can see almost behind them. Now, their binocular vision — they don't see details as much as us. They actually have to be 50% closer to see similar detail that we would, or a predator with binocular vision would.

[13:16]

The other thing to remember about their binocular vision in the front of their face is they have a large blind spot anywhere up to four feet away in front of their nose — they can't see. So anytime you're around horses, you’ve got to be really careful. That's why we always try to say come at them from the side, because they can see you coming. The blind spot in front of their nose — you’ve got to be very careful. That's why when you touch, sometimes when you reach out, they can't see your hand or arm. Horses will shy away because they can't see that, and suddenly they have something touching their nose they didn’t expect. So you have to be very, very careful — they have that blind spot right in front of their face.

[13:58]

Another one to be very, very careful about is that 10 degrees behind them, where if a horse is looking straight ahead they cannot see directly behind their tail. So that is why we are always cautious approaching horses from the rear. Something I've always taught students — riding, teaching riding, handling, saddling — be very careful behind a horse, because if they can't see you and it spooks, they can reach out and kick and hurt you severely. So always be careful with that.

[14:35]

Again, the two blind spots: directly in front of their face, and right behind them. But if you are coming from the rear or behind and you make noise and let them know you're there, you'll see they will turn their head to the right or the left, and they'll be able to see you with their monocular vision — and then that helps them relax.

[14:54]

The other thing is horses are very acute at picking up slight movements that might be invisible to us. So, you know, the flickering wings of a butterfly… that mountain lion… if there's any movement, the horse will see it — and instantly, they could be gone. That's how they've been able to develop these senses. They are super senses compared to us.

[15:18]

They have excellent night vision. It's been said if there's a partial moon or just really bright stars, horses can almost see as well as we do in the day. But like I said, it takes them longer to adjust to the darkness. So going from outside, say, into a dark barn or through a doorway that's dark — the horse has a really difficult time seeing in there, and it takes them anywhere from 15 to 30 minutes for their eyes to fully adjust. So it's really good to understand that it takes them time to go in these different light conditions, because that affects their behavior.

[15:57]

If a horse is scared or worried about survival, they'll go into that fight-or-flight mode — and that's not what you want. The wonderful thing is, horses have developed so much trust with us and their handlers, and it took hundreds of years, as we talked about in domestication, to get them to these calm and trusting behaviors. But again, if they feel like they're in danger — and anybody that's trained horses to enter a trailer — that is a difficult process, because you're going from a light to a dark area that they can't quite see well in.

[16:36]

The other aspect of this is how horses see color. They are not color blind — they are what is called dichromatic. We are trichromatic — so we see reds, blues, and greens. Horses, with dichromatic vision, can only see two wavelengths of light, or two colors of different light. So they see blue and green colors, but they cannot distinguish red. Researchers call it like red-green color blindness that we see in people. So any red colors are going to appear more green or yellow to them — it's not going to be these bright, vibrant colors that we see.

[17:18]

That means, for anybody that does show jumping, the colors of the jumps matter, because the horse is going to have a more difficult time seeing some of these colors or color patterns. It's always good to keep that in mind.

[17:28]

Now, when it comes to shadows, horses have problems with depth and shadows. So their sharper contrast — the way they see the world — darker spots appear to be deeper than lighter spots. So things like cattle guards that you see around the world — those little slats — seem like really deep troughs to cows and other animals. They have trouble navigating the world like that. For a horse, shadows across the ground can look like deep pits.

[18:11]

It really got me thinking — it just gives me a deeper appreciation for our equid companions: the amount of trust they give us, the amount of love, the amount of dedication. But just riding, and riding through shadows, and that trust that the horse has with us, with the rider. So anybody that show jumps — the deep love you have for your animals, I understand it, because it takes so much trust. As that horse approaches the jump, they lose sight of it — they can't see it — but they're trusting you to guide them. Shadows across the ground — anytime you trail ride, anytime you're galloping along, cantering, or trotting — that horse trusts you. These animals give us everything. I mean… wow. This is why we're doing this podcast, right? And that's why you're listening. They are just that incredible.

[19:14]

Now, as I leave sight — because it is probably one of the more important senses — like I said, there is a very good horse vision simulator. It's a little dated, the technology, and maybe something better will come along. I think it's French that put it out, but it's a horse vision simulation that's on YouTube. I'll put the link in the show notes, but it gives you an idea of how the horse, compared to the rider, navigates the world. It's a quick two-minute video, and I really urge everybody to watch that — it gives you a really good idea of how they see everything.

[19:59]

Now, moving on — because we spend so much time on sight, and maybe it's something in the future we can revisit, eye problems and all of that — it's such an important part of horses. The next one I wanted to really talk about — sense — is hearing. Because anybody that's worked with horses, or you learn from a young age (and I've always taught this), that the horse's ears are the barometers of their mood. It is going to tell you everything — mostly everything — about that horse, how they're feeling. And it gives you warning signs if you push them too hard or too far.

[20:40]

So, one of the things is when the ears are pricked forward, it means they're generally interested — or they could be in alarm. Standing tall, head up, eyes wide, smelling, looking around, looking for threats. Or they can just be interested in, “Oh, who's that? Oh, here comes my owner! Oh, it's feeding time!” They get really excited. When the ears are more relaxed or to the side, that usually means they're either in a good mood or they're relaxed — they're not in that fight-or-flight mode. And then, when those ears are pinned straight back, that usually means they're angry, distressed, and they're in fight-or-flight mode.

[21:16]

We're going to talk way more about behavior because it's such a fascinating aspect of these animals, but that's one thing to always keep in mind when looking at the ears of a horse.

[21:22]

Now, the way ears work — and horses and donkeys… donkeys have much bigger ears than horses, and we'll talk about why here in a minute — is they're used to collect sound waves. So, listening to my voice on your phone, in your car, on your computer, your tablets — wherever you're listening to this — it is producing sound waves that you're picking up in your ears. Horses, with sound waves, that sound is funneled down into the ear canal. When it reaches the eardrum — and we call it the drum because it vibrates — the sound waves will make it vibrate.

[22:08]

Right behind the eardrum are some bones called ossicles, and in the horse it's the hammer, anvil, and stirrup that vibrate. Those vibrating bones then vibrate the fluid-filled cochlea, which is right behind there, and it ripples and creates waves. Then, hair cells inside the cochlea ride the waves, and they move, and they send out electrical signals. These hair cells are what can detect different frequencies. They're then transferred to the auditory nerve, to the brain, to interpret the sounds.

[22:45]

Now, that's the very quick, fascinating look into physiology. It is just… when you start to study physiology and biology, it blows you away at every turn about how everything works. It just is amazing — and the horses do this very, very well. They actually have greater acute hearing than we do. And you would think they would need to — surviving for millions of years, they need to develop really good hearing to hear that soft crack of a branch or a twig, or something moving in the bushes, to survive.

[23:28]

So, for us humans, we can perceive sound in the frequency range of 20 hertz to as high as 20,000 hertz. Where horses — they go anywhere from 55 to 33,500 hertz, and they're very, very sensitive to low-pitched and higher-pitched sounds. The large ears on horses and donkeys make it easier for them to locate sound and amplify it. Also, both of them — all equids — can rotate their ears almost 180 degrees. And there are 10 different muscles, by the way, that control their ears.

[24:06]

When you watch them and watch their behavior, you watch those ears constantly scanning like radar, going back and forth. Or if there's a sound over here, they'll rotate and hold it for a second — listen in — “Okay, not interesting,” they'll go back down to being relaxed. It's fascinating to watch, and their ears are very, very sensitive, and it is one of their acute senses.

[24:30]

Now, donkeys have longer ears because — think about where they've evolved. We've talked about this: our domestic donkeys are from African wild asses. The African wild asses live near the Sahara Desert, or in the Sahara Desert, so very arid regions. The longer ears help them hear better from far away — up to 60 miles, which is nearly 100 kilometers — so they can communicate with other donkeys. And also, it helps them thermoregulate, because with more surface area, they're able to dissipate heat better. So there's a reason their ears are longer.

[25:13]

Now, the other aspect of hearing is sometimes you might hear people say that horses can “hear through their bones,” and that's either low-frequency or an ultrasonic type of sense. Some people think they can hear through their hooves on the ground, or even pick it up on their muzzles when they're grazing. There has been a lot of research done in elephants — that elephants communicate through ultra-low-frequency sounds, low grumbles and grunts, that we can't hear.

[25:46]

To explain this: a low-frequency sound has really low waves — they're not high-pitched. High-pitched is like “bing, bing,” goes really high on the scale. Low frequency, or low waves, can travel further along the ground. High pitch dissipates really quickly. Elephants communicate over 100 miles through these low-frequency sounds that they pick up in their feet and their trunks. As they go, they'll keep their trunks on the ground and they can pick that up.

[26:16]

Scientists think horses can do this — we just haven't been able to prove it yet with science. But it would make sense. Think of a cattle stampede, or a stampeding herd of horses — you can pick that up. To me, that would be like, “Oh, danger, something's chasing them.” Or, if I'm a wild horse out in the plains, or a zebra in Africa today — other animals are stampeding, I can pick that up through my hooves, turn, look — “Oh yeah, here we go” — and gone. So that's another way they can, quote-unquote, “hear” these low sounds.

[26:52]

So we've talked about sight, we've talked about hearing — two very, very important senses. Then the next one, probably for horses, that's pretty critical — and I would say touch is probably one of the most critical too — but is smell.

[27:08]

So, to talk about how we and horses smell: smells are chemicals. Think perfume, cologne — very strong — those are chemicals that are inhaled through the nose. And we have olfactory receptors, and horses have them too. So, at the top of their nasal cavity, they have many receptors, and they connect to the brain to interpret smell. Horses have a very, very keen sense of smell, which — again — a stinky predator has been eating some carrion, stinky breath, whatever — they can detect it.

[27:43]

That's why, when they smell, smell is such an important thing for them. They can identify friends, they can identify foes, they can smell medicine in their feeds and sort it out. Anybody that's tried to feed horses something they didn't want to eat — it can be frustrating, because their senses are so acutely tuned to any changes in their environment. And smell is important for them for eating, which we'll talk about.

[28:12]

So, a lot of things that we do — whenever I meet a horse I don't know, I put my hand out. They see it, they can smell me — I'm not a threat — and then they'll allow me to touch them. When we go to tack up a horse, we let them smell the equipment, smell the tack — it's not a threat, and they relax.

[28:32]

The other aspect of this smell is the Flehmen behavior. This is, you know, when horses make that funny face — they will pick up a smell, roll their upper lip back to get a deep inhalation, and they have this vomeronasal organ that detects pheromones and different odors, very, very strong odors. They breathe in these strong odors, the vomeronasal organ expands and contracts, and sends the aroma to the brain. And that's where they will display this Flehmen response.

[29:08]

You see this a lot with stallions. Anybody that's handled stallions — you know when you're either teasing mares or teasing the stallion — they usually will go and… to see if the mare's in heat. If she's got estrogen in her urine, he will detect that, get excited, and that's how they mate. You see it in other species too — you see it in tigers, and predators, and other animals.

[29:32]

One final piece of this is horses only breathe through their nose — they cannot breathe through their mouths like we can. They can't pant like dogs, inhale through their throats — it only is through their nose. So that's very important for anybody that owns horses — that you never obstruct their nose with anything that can inhibit their ability to breathe. Very, very important to remember that.

[29:57]

All right, before we get to touch, taste real quick. How does taste work? Again, through chemicals — taste buds on the tongue. Most are on the first two-thirds of the horse's tongue and the roof of their mouth, but many of their taste buds don't have what we call gustatory function — or that's what we consider taste. A lot of these taste buds they use for texture and feel. Horses also have a lot of taste buds in the back of their throat, so it really helps them detect if something tastes good or is poisonous.

[30:30]

They do have the ability for sweets, which we know — we used to feed a lot of sweet feed in the day. We still flavor some of our feeds with molasses, peppermint snacks, things like that, that horses seem to enjoy. They also can taste salt, so we add salt to feeds to make it a little bit tastier for them. They also can taste really bitter plants, which helps them learn to avoid weeds and other noxious plants that can cause them harm or kill them. There are plants out there that, if a horse eats enough of it, can kill them. And again, feeding them medicines that are bitter — they can taste that.

[31:12]

I did a trial with arginine — an amino acid — back in the day. It was so difficult to get horses to eat it. We tried to mask it with applesauce and other things — they just have a good sense of taste. So it does play a big role, but also smell does too. When they go to those plants, they'll smell it — “Oh, it smells good.” Taste — “Taste is okay.” They'll chew it and swallow it. If it doesn't taste good, they will refuse their feed, or they'll sort their feed and find the good parts that they like, or they'll just avoid it altogether. Life of a horse owner, right?

[31:48]

The final sense that's important — and this one we’re definitely going to have another podcast on, especially when we talk about training — is touch. The skin is the largest organ on the body of any mammal. For us, for horses, it is an organ. The outer layer is the epidermis — this is what protects us from the hostile environment we live in, of bacteria and viruses and things like that. The second layer of the skin is the dermis — this has the sweat glands and receptors. The receptors in the dermis are what detect pain, pressure, and temperature, and feed all those signals back to the brain through the nervous system. The hypodermis is the last layer that helps regulate temperature and hair growth.

[32:47]

The other aspect that's important for horses to know is their whiskers. That's why you no longer see many people shave a horse's whiskers, because those are so important for them navigating their environment. It's become less fashionable to shave those because, again, they have that blind spot in front of them, so they use the touch of their mouth and their whiskers to navigate the environment while they graze. People have said it's like the horse using our fingertips — that's how sensitive they are. And that carries through the rest of their body — very, very sensitive to touch.

[33:22]

That's why they can feel a fly — and you see it. You just watch a horse: a little fly lands on them, and they've got that muscular control in the skin and they can shake it and the fly flies off, or they'll turn to bite it, or they'll use their tail to whack at it. Very, very sensitive skin — and that's important when it comes to training a horse, grooming a horse — not scraping really tough with some of those brushes. Their skin, their hides, are sensitive. We just have to be cognizant of that.

[33:50]

This is also a breed difference too — some Thoroughbreds have really sensitive skin because it's thinner than, say, a draft horse, where they have thicker skin and might not be as sensitive — like a Clydesdale versus a Thoroughbred. Other things to keep in mind when it comes to touch as sensitive areas — any areas with bone can be really sensitive because there's no fat or muscle on there to relieve some of that pressure: around the head and face region, lower legs, shoulders. Just be sensitive to that.

[34:29]

Horses are sensitive along their backs, their sides — places where we ride and deal with them quite a bit. Their ears, their mouth, and their nose are sensitive too. That's why when you touch — and kindly touch — a horse and scratch them a little bit, they quite enjoy that because it is sensitive. When it comes to pressure, just so you know, horses will want to move away from it to get away from that stimulus. That's a big thing when it comes to training a horse. But if you're ever handling them or touching them — obviously, there's bonding — a lot of bonding goes on along grooming with horses. It's important as they touch each other. But sometimes, if that touch isn't something that they really enjoy, they will move away or try to escape from it.

[35:27]

So keep those things in mind. It's just such an important thing for how horses interact with us and other animals. So, just to tie this all up: we talked about eyesight, we talked about how horses hear, we talked about how they smell the world, how they taste their food and other objects, and then how they touch. It is such an important aspect of horse care that I encourage everybody to jump in a little bit more, read some articles about how horses navigate the world — because it has such an impact on your relationship with them.

[36:15]

[Music] Welcome back — just some housekeeping again. Such an important topic — it is such an important topic. I could probably do a podcast on each and every one of those, and we may in the future. We may jump into it a little bit more. It’d be really interesting to pull out some of the scientific literature too and see some of the research studies that have been done. But I always feel it's important to do the broad topics up front, and then we can drill down later in a year or two on some of these topics.

[36:46]

Please let us know if you want to learn more about anything specific — you can email me at podcast@madbarn.com. Also, just a reminder, if you don't mind subscribing to the podcast — Spotify, iTunes, whatever you're using — if you don't mind, just click subscribe, keep up with the episodes. We're going to be pushing these out as fast as we can get them done. We're really trying to get as much information out there as we can.

[37:14]

Another great resource is to go to madbarn.com, look under the Learn tab, and you'll see we do have a link to videos, the podcast, but also articles — over 400 articles written by PhDs, DVMs, equine enthusiasts with master's degrees that have been working so long in the equine industry. Such a wealth of knowledge — so many topics: signs your horse is happy, hoof problems in horses, skin diseases, colic causes… anything that you're thinking of, it should be in there. We're kicking out articles every single day for the website. We want to be a depository of knowledge and your one-stop shop for everything.

[37:58]

So let us know if there's any topics that we haven't covered that you really want us to learn more about. You can interact with us too on social media — Instagram, Facebook — look for Mad Barn, and you can contact me there too. Thank you for listening. Stay tuned — we’ve got more episodes planned. We're going to keep going and going and going — and making the world a better place for horses and for you. Thank you.