The trio of accomplished horses and riders profiled on NATURE’s Horse and Rider have one thing in common: they know how to communicate. Indeed, when it comes to “cutting” a cow from a thundering herd, chasing down a polo ball at breakneck speed, or developing the discipline necessary to perform the ballet of dressage, horse and rider need to know exactly what the other is thinking. Misunderstandings could literally be fatal.

Such clear communication, however, takes time for both horse and rider to learn. Luckily, a growing number of experienced “horse whisperers” — men and women who have developed a special knack for getting their point across to their mounts — are sharing their secrets with riders, through everything from books and videos to conferences and workshops.

One of these teachers is Mark Rashid, an Estes, Colorado-based cowboy who has written three books on horsemanship (he’s at work on a fourth), and holds dozens of clinics with riders every years. His Web site, Considering the Horse, has become a popular watering hole for riders seeking to develop stronger relationships with their mounts. It offers heaps of practical advice, honed by decades of experience working on cattle and dude ranches, investigating cases of abused horses, and teaching greenhorns and veteran trailriders alike.

NATURE recently caught up with Mark early one morning in Washington State, just before setting out to work with a waiting group of equine and human students.

NATURE: When did you first take to horseback?

Mark Rashid: I’ve been working with horses since I was about 6 years old. I wasn’t raised on a ranch, but there was one about 3 miles from where I lived in Wisconsin. I spent all my days there for 4 or 5 years.

How did you come by training?

It was by accident. In the 1980s, I was up in the Colorado mountains doing a lot of ranch work on cattle ranches, dude ranches. I was working with hundreds of horses, including problem horses that had a large variety of [problem behaviors such as bucking, not stopping, etc.]. I also worked with a lot of people, trying to teach them how to have a good ride. But I wasn’t very good at it, because I hadn’t learned to communicate. But I realized that working with people was a lot like working with horses: they need to understand what they are expected to do before they can have a good ride.

Later, I was a horse abuse investigator for the state of Colorado, and that gave me some experience communicating with people [who were having trouble caring for their horses]. Then, someone called me to come work with a problem horse. Next, their neighbor called. It just kind of grew from there. Soon, I was working with whole groups of people and horses. Now I hold clinics around the world.

What’s your philosophy?

Basically, I try to help folks get along better with their horses by finding some common ground so they can accomplish what they want to accomplish. I have two main messages — Don’t fight; and be clear. If you can do those two things, it opens the door for pretty much everything else.

The vast majority of horse training is designed to find the bad stuff horses are doing, so we can fix it. I try to find the good behavior, so we can build on it. That doesn’t mean we ignore the bad, but we don’t hit it head on. You try to work around it.

Mark Rashid teaches riders how to communicate with their horses.

Can you give an example?

Well, a lot of people will come to the clinics and say, “My horse doesn’t stop when I want it to.” So, I’ll ask the rider what constitutes a good stop? How many steps do they want the horse to take before it stops? Well, often they don’t know — they haven’t thought about it. They get an idea in their head as to what they want to do, but don’t give a lot of thought as to how they are going to get there.

So the first step is to break things down. Before the horse can know what it is supposed to do, the rider needs to know exactly what he or she wants. Then, you can start making some progress, such as working on how much pressure [the rider can put on the reins] to make the horse stop.

What do you mean by “don’t fight?”

Horses are usually happy to do whatever we want them to do — if they know what we want. But if you come in with the attitude that the horse is [intentionally disobeying], you set yourself up for a confrontational situation, and it all goes downhill from there. But if you say, “I’m not going to fight with you,” you open lots of doors.

Then, people often realize the problem is that they are applying cues that the horse doesn’t understand. It’s a basic misunderstanding from the get-go. It would be like going to Germany and speaking English to everyone and assuming they would understand. It isn’t going to work.

So you help people think about why they are having problems with their horses?

Yes. I really urge everyone to look at all kinds of possible explanations [for problem behavior]. Sometimes, it’s not really a training issue. You have to make sure the saddle fits properly, that the horse doesn’t have some kind of a chiropractic issue. Horses can be stiff or sore. We see a lot of teeth and feet problems. Basic horse care can solve a lot of problems.

What techniques do you use to get your ideas across?

One thing I do at the beginning of some clinics is that I split the people up into “horses” and “riders.” Then, the “riders” have to go back and teach their “horse” a task — such as walkng in a figure eight, then jumping a fence, and then sitting in a chair. But they can only use the words “good” and “no.” Yesterday, we did it with 10 people, and only one of the “horses” understood exactly what it was that their “rider” taught them. The vast majority of the time people can’t get it done. So they realize how important communication is.

Then, I have my students pick a task for me to teach a “horse.” And they come up with some weird things. Once, I had to [teach the "horse"] to write my name backwards in the sand with his foot. But I did it. You just have to keep up a steady stream of “goods” and “nos,” and not just communicate once every so often. You have to be clear about what you want.

Diana monkeys are some of the most clever monkeys when it comes to language.

We all know the expression monkey see, monkey do. But should the saying really go monkey hear, monkey do? Recent studies are finding that the language abilities of some monkeys are more sophisticated than previously believed. Much more sophisticated.

Monkeys live together in social groups. All members contribute by helping to defend food sources, raise young, and watch for predators. But it is impossible to live in a social group without some form of communication. Group members need ways to influence and inform each other. This is what drives language. Monkeys have evolved many ways of communicating, including visual cues, auditory calls, and even some olfactory signals. Some of their visual signals are quite beautiful, like the long, curled tongue of the emperor tamarin, signaling to her mate when she wants to offload her babies. But visual signals only work if they can be seen. In the dense forest and underbrush that most primates live in, auditory cues are a much more powerful tool. Calls and vocalizations can also be modified in pitch, loudness, and duration, which means a vast array of messages can be transmitted. Alarm calls, territorial calls, food calls, personal identification calls, dominance calls — these are the basic messages that primates need to successfully live in groups. But some developed more complex and specialized forms of auditory communication. Some developed language.

No animals have all the aspects of human language, but several species have some. Diana monkeys, seen in Clever Monkeys, are some of the most clever monkeys when it comes to language. They combine calls to make sentence-like messages. This requires grammar. The meaning of the “sentence” depends on what sounds are included and in what order. Added sounds convey more information, like “maybe,” or “not urgent.” Each predator has an assigned call. The eagle call differs from the jaguar call, meaning Diana monkey language includes semantics: signals convey meaning and refer to features in the real world. And what’s more impressive is that the Diana monkeys can understand other species of monkeys. Putty-nosed guenons also combine calls, and their messages can be understood by the Diana monkeys. A remarkable example of multilingual primates is seen in Clever Monkeys, with eight different monkey species living together and listening to each other. With eight times as many eyes on the lookout, it’s much harder for predators to go unnoticed. Each of the eight species has at least 15 distinct calls — that’s 120 different sounds to remember. There aren’t many humans that speak eight different languages.

One of the most interesting aspects of human language is the ability to deceive. Some primates are capable of displacement, or the use of language to refer to things that are not present. Monkeys use both spatial displacement, referring to objects that are not present in that space, and temporal displacement, referring to objects that are not present at that time. The white-faced capuchin in Clever Monkeys that uses displacement to deceive his troop had to think abstractly about invisible objects. And he had to predict how others would respond. It takes impressive intelligence to tell a monkey lie.

It also takes impressive intelligence to live in very large groups of up to 800 individuals like the geladas of Ethiopia. Within the larger band, gelada males are chosen by females, and they live within harems of females. But staying on top of the social order takes a lot of maneuvering. Most importantly, being a dominant gelada requires a high level of social intelligence and an ability to use visual and auditory signals to communicate. Geladas have over thirty distinct vocalizations. These vocalizations can indicate social status, identity, alarm, friendliness, or submission. Grooming strengthens bonds between group members and brings overall stability to the family unit, but geladas spend most of their day shuffling from spot to spot, picking grass with their thumbs and index fingers. With little time to groom, “chatting” has become a substitute way to relieve tension. This is perhaps what our origins resembled, learning language as we moved across the plains.

Photo by Trisha Shears, Creative Commons license.

by Irene Tejaratchi

Dolphins use sound to detect the size, shape, and speed of objects hundreds of yards away. Fascinating and complex, the dolphin’s natural sonar, called echolocation, is so precise it can determine the difference between a golf ball and a ping-pong ball based solely on density. Although humans have researched these intelligent marine mammals for decades, much of their acoustical world remains a mystery.

One of the keys to dolphin echolocation is water’s superb conduction of sound. Sound waves travel 4.5 times faster in water than they do in the air. Dolphins use this to their advantage, in ways that would make a superhero envious. Using nasal sacs in their heads, dolphins send out rapid clicks that pass through their bulbous forehead, or “melon.” The sound is focused, then beamed out in front of the dolphin. The sound wave speeds through the water, bounces off the object under investigation, and is reflected back to the dolphin. Fat-filled cavities in the dolphin’s lower jaw receive this information and auditory nerves conduct it to the middle ear and brain, where an acoustic picture is created.

Scientists say that dolphins may also use clicking to communicate with one another. Although dolphins do not possess vocal cords, they still “speak” using sounds such as whistles, squeaks, and trills. A mother dolphin may whistle to her newborn for days, apparently to imprint a signature whistle upon her baby that will enable it to recognize her. It is believed that dolphins use whistles to identify one another and possibly for other functions, such as communicating strategic alerts while hunting in a group, but scientists have yet to crack the code. Many doubt, however, that dolphins have a formal language akin to that of humans.

In the 1950s, researcher John C. Lilly helped pioneer the systematic study of dolphin vocalization. A strong advocate of interspecies communication, Lilly wrote several books about dolphins, inspired the film Day of the Dolphin (1973), and was a supporter of the Marine Mammal Protection Act of 1972. Another pioneer of dolphin research, Kenneth S. Norris, first obtained evidence of dolphin echolocation by blindfolding a bottlenose to test its ability to locate an object underwater.

Since the 1960s, American military scientists have studied dolphins, and have trained them to perform such tasks as attaching explosives and eavesdropping devices to enemy ships or submarines. In the mid-1980s, the U.S. Navy began training dolphins to search for mines using their echolocation. In 2003, dolphins were deployed for the first time in a real war situation to probe the seafloor for mines near the Iraqi port of Umm Qasr. For decades, animal activists have opposed the use of dolphins for entertainment or military activities, citing questionable training methods and the stress-related illnesses, such as ulcers, that the animals can manifest in such situations.

Dolphin advocates also object to the navy’s use of manmade sonar, which is used to scan and investigate the ocean depths, claiming that it is harming dolphins and other marine mammals. They point to incidents such as the beaching of four different whale species off the coast of the Bahamas in March 2000, following navy sonar exercises in the area. Marine mammals strand themselves for a variety of reasons, but investigations confirmed that navy sonar caused the Bahamas stranding. Researchers are not exactly sure how manmade sonar affects marine mammals. Some believe the intense sounds may scare or disorient them and cause them to rapidly flee to the water’s surface, resulting in a sort of decompression sickness that damages sensory organs and causes internal bleeding.

If technological sonar can be implicated in the death of dolphins, it would be a tragic irony, considering that the sonar is based in part upon nature and dolphins’ superior echolocation capability. Efforts to replicate dolphin echolocation continue to fall short, as humans have yet to achieve the complexity and precision that 50 million years of evolution has bestowed upon dolphins. Perhaps if scientists could understand dolphin-speak they’d have more luck, but for now the true nature of dolphin communication remains mysterious.

As we learn in NATURE’s Murder in the Troop, life for a chacma baboon is defined by strict hierarchical structure. Among the most highly socialized of animal species, chacmas rely on a complex and varied communication system in order to candidly express themselves to family, friend, and even foe. The following are some examples of the visual signals, vocal gestures, and body language they use to get their message across.

Chacma baboons draw upon a rich repertoire of vocal signals to express themselves. Adult males may assert their dominance in a troop by emitting relatively soft, but threatening “uh huh” sounds that are referred to by primatologists as “grunts.” Grunting commonly precedes a “two-phase bark,” which is a deep, loud “wa-hoo” call, emitted at intervals of 2 to 5 seconds. This call is frequently directed in aggression toward other males or an approaching predator.

But antagonism on the part of a male may evoke the equally powerful vocal response known as “screeching.” In a series of high-pitched screams, male and female baboons of all ages use this vocal tactic in their defense, as it appears to inhibit the hostile behavior of the aggressor.

When retreating from a threatening animal, subadult and adult baboons may emit a short, sharp “yakking” call, while infants and juveniles produce a chirplike “clicking.” These sounds are often coupled with a “fear-grimace” in which the animal retracts its lips and exposes its clenched teeth. This display serves as a pacifying gesture and is used to avert an aggressive encounter. Infants in distress may also emit a cry known as an “ick-ooer,” a two-phased call made through pursed lips.

In the case of immediate danger, all members in a troop, with the exception of the adult males, engage in a “shrill bark” — an explosive, single, sharp cry of alarm that alerts troop-mates to flee. Higher in pitch than the shrill bark is the “doglike bark,” sent out by subadult and adult baboons when members are thought to be separated from the troop.

But not all calls are designed to communicate aggression, fear, or danger. The animals articulate friendly intentions through low, soft “rhythmic grunts,” interpreted as an amiable greeting when one individual approaches another. Juveniles at play are often heard emitting nasal “chattering,” which involves rapid murmurs that signal, at least for the moment, all is well in their world.

Whether on the giving or the receiving end of a glance, nod, smile, or stare, we can all appreciate the power of visual communication. A look, as they say, is worth a thousand words. Adult male chacmas have earned a “tough guy” reputation. And while violent fights do occur, they can be costly. Injuries sustained during conflict may lead to infection and the inability to forage or travel, and could leave the troop more vulnerable to predators or rivals. Therefore, it is in the baboons’ best interest to avoid coming to blows. Visually assertive displays may serve to get a message across before the situation escalates into a physical brawl.

“Staring” sends a crystal-clear warning. In this penetrating glare, the baboon raises his eyebrows while keeping his eyes trained on his subject. To enhance the menacing effect, he will move his ears back so that the skin on his face and scalp is stretched taut, revealing a differently colored fur beneath his eyes. It is a signal that the recipient would be wise to heed.

A “canine display” is sometimes presented by a lower-ranking male to test a male of higher rank who is consorting with a female. A quick flash of the teeth serves as a threat and is often accompanied by “eyebrow raising,” which is viewed as an antagonistic gesture in itself. In order to avoid a scrap, a baboon on the receiving end of these visual cues may respond by “rapid glancing,” turning his head in the opposite direction and shifting his eyes to ease the tension of the situation. Another means to avert an aggressive encounter is through a “fear grimace,” in which the baboon retracts its lips and exposes its clenched teeth. This expression is usually accepted by the aggressor as a pacifying gesture.

But hostile displays aren’t only directed at troop-mates; they are also useful in defending the group. When a predator or rival troop approaches, an adult male is often effective in repelling them by opening his mouth widely in a “tension yawn,” fully revealing his formidable canine teeth.

Nonaggressive visual cues are also highly important in chacma society. “Social presenting” is a submissive act in which a female or juvenile exhibits their hindquarters to a higher-ranking male. A female may also present to a mother with an infant as a gesture of respect. She often embellishes this act by “lip smacking” to signal her affiliation with the troop. In this display of reassurance, the baboon protrudes and smacks its lips together repeatedly. Along with “teeth chattering,” this is also performed by a dominant male when a female or juvenile is presenting to him.

Perhaps no form of communication sends a more vivid and direct message than that of touch. Whether used to extend a friendly greeting, to soothe or support, or even to intimidate, it is difficult to misinterpret the meaning of a tactile signal.

Like all primates, chacma baboons spend a significant amount of time expressing themselves through physical contact, from reassuring touches and pats to antagonistic bites and swats.

When two individuals meet, they will cordially touch muzzles and acknowledge each other in an amiable “nose-to-nose greeting.” Chacmas also engage in “social mounting,” which is generally a response to social presenting. Though it resembles a sexual mount, the baboon has no real intention to mate. In most instances, social mounting signals friendly reassurance, but it has been noted by primatologists to occur during aggressive encounters as well.

But the one form of physical expression held sacrosanct in chacma society is “social grooming.” In addition to the hygenic benefit of removing parasites, dead skin, and debris from the fur, grooming is also thought to reinforce social bonds between animals. For the baboon being groomed, the experience of having its hair pulled is highly pleasurable, as it releases endorphins that produce a natural high. This helps to alleviate stress and build trust among members of the troop. In fact, studies have proven that the levels of stress hormones, called “glucocorticoids,” drop significantly in chacmas after they engage in grooming behavior. 

After years observing elephants in the wild, filmmaker Martyn Colbeck has learned how vast –  and how mysterious — the realm of elephant communication is. Elephants rely on a complex communication system to sustain their clan-based society. At the root of it is a common language.

Long-lived and large-brained, elephants are not only capable of expressing complex thoughts using this common language of intricate acoustics, they have a great deal of social and ecological knowledge to share.

Elephants have a wide range of calls and signals for different purposes — to secure their defense, warn others of danger, coordinate group movements, reconcile differences, attract mates, reinforce family bonds, and announce their needs and desires. Researchers like Joyce Poole have been trying to crack the code of the elephant communication for years. Poole has found that the elephants use more than 70 kinds of vocal sounds and 160 different visual and tactile signals, expressions, and gestures in their day-to-day interactions.

Vocal calls

Vocal calls are likely the most common way elephants confer. Calls are used for everything from caring for calves, reconciling differences during disagreements and coordinating the group’s next move. At the end of a meal, when it’s time to move on, one member of a family moves to the edge of the group, typically lifts one leg and flaps her ears. She repeats a “let’s go” rumble, which eventually rouses the whole family, who then hit the road. An elephant can recognize the calls of hundreds of other elephants from a half-mile away.

That famous shrill trumpet call is the one we most often associate with elephants but the creatures can also squeal, cry, scream, roar, snort, rumble, and groan to get their point across. Whatever form the call takes, it can be soft, abrasive, low-pitched or shrilling. There’s even a place for jackhammer-like ear splitting blasts as a danger or alarm call to signal others to form a protective circle around the younger members of the family group.

But of the motley assortment of calls in the elephant repertoire, deep growling or rumbling noises are, by far, the most common. Some researchers even postulate that each individual has its signature growl.

A recent discovery is that much of elephant language exists in a range that humans can’t even hear. The deepest sounds we can hear, the grunts or rumbles, are the mild overtones of low frequency sound from 1 and 20 Hz, which is below the level of human hearing. Such sounds are so low and powerful they travel unhampered for miles through forest, allowing elephants to send messages and warnings over long distances. These powerful, distant-traveling sounds are critical in helping males find females for breeding. Researchers say the infrasonic calls also enable elephants to reunite with friends and family members. One rumble means “Hello, I’m here,” another “Help, I’m lost” — important messages for helping separated family groups find each other.

Breeding herds also use low-frequency vocalizations to warn of predators. Adult bulls and cows have no enemies, except for humans, but young elephants are susceptible to attacks by lions and hyenas. When a predator appears, older members of the herd emit intense warning calls that prompt the rest of the herd to clump together for protection and then, if necessary, flee the scene.

One call researchers have just deciphered is the “contact call.” This call helps elephants locate distant family members. The elephant seeking to make contact lets out a powerful reverberating sound, after which it lifts its head to listen for a response. If it receives one, it emits an explosive sound. The pattern is repeated, possibly for hours, until the elephant successfully rejoins her family. Any reunion of elephants is met with an exuberant greeting. The greeting ceremony, as it’s called, is marked by trumpeting, screaming and rumbling.

Because males and females dwell in separate social worlds, different methods of communication exist for both. Researchers have found that females have the most extensive vocal repertoire. Seventy percent of all known calls are made by adult females, juveniles and calves, leaving only thirty percent for adult males.

Vocalizations are essential for the mating ritual. Males, with their solitary life, rely on calls to announce their sexual state, identity and rank. A bull in musth (or in breeding state) signals that he desires sexual activity by displaying specific courtship behavior, which includes the emission of scent, discharge of bodily fluids and broadcasting of infrasound calls. Such low, powerful calls carry more than 2 miles in the air. The infrasound call signals to other bulls to keep away, as bulls in musth are aggressive and dangerous. The cow has her own set of mating behaviors and calls. A female can broadcast her receptive state to bulls miles away, also through infrasound calls. After mating, the female rumbles out the post-copulatory sequence, a group of six grunts with strong overtones. She repeats this sequence several times, continuing for up to half an hour.

Non-vocal communication

Touching, caressing and smelling each other with their trunks also helps elephants maintain their social bonds. Tactile sensations are very important to communication in elephant society. Trunks are essential to their tactile sense. They use their trunks to caress each other or explore other objects. For instance, elephants communicate their interest in death when they touch and smell bones of dead elephants with their trunks. Members of groups passing one another in the brush will pause to exchange touches, while courting bulls will intertwine their trunks with the trunks of cows. Researchers have found that elephants also appear to communicate by sensing seismic vibrations through the soft skin on the pads of their feet. Elephants may also lay their trunks on the ground to detect vibrations in the earth.

One distinct behavior of elephants in the wild is synchronized freezing. Remaining motionless helps elephants focus their keen senses of smell and hearing on unfamiliar noises and odors in the air. Smell is their most developed sense. With their long trunks, elephants can keep track of odors on the ground as they walk head up, and they routinely touch and smell each other’s bodies with their trunks.

Elephants rely on their varied and sophisticated means of communication not only to orient themselves properly in the world, but also to recognize, honor and somehow carry on the world of the past. Understanding how elephants exchange information and what they seek to express teaches us so much about their fascinating world.

For centuries, biologists believed giraffes were the mute giants of Africa’s plains and forests — silent sentinels gazing to the horizon. In recent years, however, new techniques and technologies have allowed scientists to listen more carefully — and realize that giraffes may be talking after all. Just not in a way that we can hear.

Over the last few decades, biologists using special microphones, recording equipment, and computer analysis programs have realized that whales, elephants, and some other animals were using extremely low-frequency sounds — far below the range of human ears — to communicate.

These low-pitched sounds are known as “infrasound,” and they have at least one remarkable property: they can travel farther than higher-pitched noises through the air and earth. Such long-distance communication is a must for animals, such as giraffes or elephants, that can be spread over vast territories. Elephants, for instance, may be able to communicate with other animals up to several miles away.

Studying infrasound, however, is difficult. In part, that’s because so many things produce infrasound, from rumbling earthquakes and thunder storms to trains and cars. Sorting out wild sounds from the background noise can be nearly impossible. But by doing studies in zoos, where researchers can partly control experiments, scientists have been able to document the existence of infrasound and show that animals appear to be using it to communicate.

TALL BLONDES documents the work of one of these sound scientists. In 1998, Elizabeth von Muggenthaler of the Fauna Communications Research Institute in North Carolina and a group of colleagues announced that they had found evidence that giraffes use infrasound to communicate. In part, Muggenthaler had taken on the study — done on 11 giraffes at 2 zoos in North and South Carolina — because she had studied the use of infrasound by the Okapi, a relative of the giraffe. It would be natural, she thought, for the giraffe, which shares many behaviors with the Okapi, to also share the use of low sounds.

In their zoo study, the researchers noticed that the low sounds picked up by their microphones seemed to coincide with two behaviors: the “neck stretch,” where giraffes throw their head and necks back over their bodies; and the “head throw,” in which the animals lower and then quickly raise their chins. How exactly giraffes make the low, huffing noises is unclear, however. The researchers think the answer lies in studying how air moves through the giraffe’s long neck.

In a recent interview, Muggenthaler discussed her work trying to listen to the unhearable:

NATURE: Sounds like you’ve got a tough job.

Elizabeth von Muggenthaler: It is a such a hard thing to do. You can’t hear infrasound, so you are relying totally on your microphones and computerized analysis systems to detect it. Then, there are so many other things that create infrasound — from water and wind to cars and trains — that you have to be able to eliminate what you don’t want. The environment has to be very good where you are recording. It’s hard to do in the field.

NATURE: What tipped you off that giraffes might be using infrasound?

EVM: Well, here is an animal that is very social, they hide in forests [making visual communication difficult], and they hide their young during the day while foraging. They are hunted by other animals. But they were considered mute. Right there is your clue — there are no animals [that have such behaviors] that are mute. They wouldn’t survive if they couldn’t communicate.

Also, if you look at giraffes’ ears, you know something is going on. Their ears are like parabolas and they have [features] that suggest they can tune in on sounds.

NATURE: What would it take to study the giraffe’s use of infrasound in the wild?

EVM: Well, you would really need an array of microphones, so you’d be able to detect if it’s the giraffe or not. It would be a very expensive study.

NATURE: How did you get interested in infrasound?

EVM: It’s just that we humans are so limited. I knew I wanted to study animal communication [in college] and I liked the elephant [infrasound] studies [that other scientists had done]. So I tried to replicate that and ended up at NASA, renting equipment. It was while I was recording the elephants that I got the rhinos. [Editor's note: In 1992, Muggenthaler documented the use of infrasound by rhinos.] It’s just that there is this world of crazy stuff going on with sound. There is this unseen world out there, and I want people to know it exists.