Dogs’ ears come in many shapes and sizes — long and short,
floppy and erect, and all variations in between. Dogs’ ears are surprisingly
mobile. More than eighteen muscles control the pinna, or earflap, alone, which
allows the nuanced movements that make dogs’ ears so expressive and so good at
picking up sounds. Dogs move their ears to communicate how they are feeling.
They also move their ears to facilitate hearing. Every dog owner will recognize
the “pricked ears” of a dog who is suddenly attentive. The up and open ears
allow dogs to best capture sound. The ear muscles also allow dogs to turn their
ears like a periscope to follow the direction of a sound. If we watch a dog’s
ears for cues, we can likely gather information about our surroundings that we would
have missed. Marc used to watch his dogs’ ears when hiking around their
mountain home, which they of course shared with all sorts of wild animals. When
there were cougars, black bears, or other potential predators around, the dogs’
ears perked up and their noses often tilted upward. Marc took these responses
as signals that it was time for all to head home immediately to avoid a
possible confrontation.
Dogs have far more sensitive hearing than humans and can
detect much quieter sounds. Their sense of hearing is about four times as
sensitive as ours, so what we hear at twenty feet, a dog can hear at about
eighty feet.1 They also hear a lot of things
we don’t because they can hear higher-frequency sounds. From available data,
scientists suggest that dogs hear in frequencies as high as 67,000
cycles per second (also called hertz), while humans hear frequencies up
to 64,000
cycles per second.2 This
means there are some sounds that are inaudible to us but quite available to our
dogs. For example, they can hear the high-pitched chirping of mice running
around inside the walls or in the woodpile. Also, some of the electronics in
our homes emit constant high-frequency sounds we don’t notice but which can be
distressing to dogs.
Relatively little systematic research has been done on how dogs
use sound and hearing in their interactions with the world and in their
encounters with people and other dogs. We know that dogs make a lot of
different sounds, including growls, barks, whines, whimpers, howls, and pants,
but scientists don’t fully understand how these different vocalizations function
in interactions with others. And we also don’t know which aspects of vocal
communication have evolved specifically to facilitate social interactions with
humans. For instance, dogs are the only canid species to bark frequently, but perhaps
surprisingly, we still don’t know all that much about what dogs are trying to
say with their barks. Preliminary data also suggest that dogs seem to “laugh.”
During play, dogs will emit a kind of forced exhalation called the “play pant,”
which seems to be used to initiate play and to signal during play “this is
still play, and not a fight.”3 It
will be fascinating to see how research into canine vocal communication
evolves.
Many people use verbal commands or vocal signals to communicate
with their dog. As we mention in the section on sight, dogs may pay more
attention to gestures than they do to spoken commands, and they may get
confused when our visual and auditory signals don’t align. Researchers have also
found that dogs listen not only for certain words but to tone of voice, and
intonation may be more important in how dogs read a signal than the actual word
spoken. Using fMRI techniques, researchers at a dog cognition lab in Hungary scanned
the brains of dogs as the dogs listened to recordings of their trainers’
voices. The trainers used praise words (such as “well done”) and neutral words
(such as “however”) and spoke them in a high-pitched “good dog” voice and in a
neutral voice. The results of this study showed that dogs used their left
hemisphere to process the words, and their right hemisphere to process the
intonation, or emotional content, of the words, which is how human brains
process speech. When praise words were spoken with a praising intonation, the
reward center of the brain was activated, but not when praise words were spoken
with neutral intonation. In other words, dogs listen to the words and the
emotional content of our speech, and the emotional content has more salience.4
Unlike other senses — particularly smell and taste — where
pet dogs often suffer from a lack of sensory stimulation, hearing can entail
the opposite problem. Dogs often suffer from too much noise or from exposure to
sounds that they find aversive or frightening, which constitute serious freedom
inhibitors. Of course, we should try to give our dogs the freedom to hear and
communicate with sounds, but we also need to think about the overall soundscape
and protect dogs from noises they don’t like.
BARKS
AND GROWLS: THE LANGUAGE OF DOGS
Barks and growls are two of the most common dog
vocalizations, and they are used to communicate with both other dogs and
humans. Vocal communication in dogs is extremely complex and not very well
understood. In her analysis of dog vocalizations, German ethologist Dorit
Feddersen-Petersen notes that even the meaning and function of barking is
controversial. Some scientists consider barking a highly sophisticated acoustic
form of expression, while others think barking is “noncommunicative.”5 Dog barking is difficult to
study for a whole variety of reasons, including the fact that dogs come in a
huge variety of shapes and sizes. There are big differences in the length of
the vocal tract and thus in the sound quality of vocalizations. Just think of
the difference between the bark of a Great Dane and of a Yorkie. Are they even
speaking the same language?
Feddersen-Petersen believes that barks have definite
communicative significance, and dogs use them to convey information about
motivation and intention. Dog barks have a mixture of what scientists call “regular”
(or harmonic) and “irregular” (or noisy) acoustic components. While wolves
vocalize using noisy components only, dogs use a whole range of harmonic and
noisy forms in various mixtures. Different breeds of dogs seem to have evolved
unique vocal repertoires, ones based on the human environments in which they
have lived. Assessing the meaning of a bark — or more accurately, a string of
barks, since barks are rarely singular — is challenging and requires looking at
the context and whether the bark elicits a response from a social partner
(either a dog or human). It may be that barking and other vocalizations have
evolved particularly to facilitate dog-human social interactions.
One way to get to know your dog better is to make an ethogram
focused solely on the various barks, growls, and other sounds they use in your
company and in the company of other dogs. Can you distinguish between different
kinds of barks — such as sharp and high-pitched; low-pitched; coming in a
steady stream or in short bursts, and so on — and can you identify what may
have triggered the bark? For example, was it the postal delivery person walking
by, another dog barking in the distance, or impatience because you are slow getting
your shoes on for the morning walk? After studying the vocal sounds of your own
dog, watch other dogs in your neighborhood or at a dog park.
Barking is a key part of the natural behavioral repertoire of
dogs and is likely an important means of communication. Letting our dogs be
dogs means letting them talk with one another, which means letting them
vocalize. Of course, barking is often treated as a problem, and “excessive”
barking — which is always defined by humans — can become a very serious issue
for dog owners. A barking dog can be incredibly annoying to us and perhaps to
other dogs and animals. Excessive barking is a common reason for dogs being
relinquished to shelters, and it can be one of the more frustrating aspects of
dog ownership. While some barking is normal, too much barking can be a sign of
boredom, frustration, or stress. Trainers and dog psychologists can often help
identify underlying issues that might drive excessive barking. If dog barking really
bothers you, it’s probably best not to get a dog.
Sometimes people deal with a dog who barks too much by
having the dog’s voice box surgically removed. In one particularly shocking
case of “problem barking,” a couple in Oregon was ordered by a court to have
the voice boxes of their six dogs removed because they had failed to control
the dogs’ barking over ten years.6 “Debarking”
— or “bark softening,” as some euphemistically (and offensively) call it —
involves severing the vocal cords and is, simply put, seriously harmful to
dogs. The procedure permanently eliminates one of the dog’s main means of
communication, which qualifies as a severe freedom inhibitor. Severing the
vocal cords is never the best response to barking behavior, and a dog who has
been subjected to this horrific procedure can no longer really function comfortably
as a dog.
In addition to barking, dogs often growl. Whereas barks are
often used to communicate at a distance, growls are generally low volume and
used in close communication. Different kinds of growls carry distinct meanings
and have different emotional content. For example, during play, including during
tug-of-war between dogs or between a dog and a human, a dog may growl quite
loudly, without showing any teeth, but this is usually meant as part of play
and not to signal genuine anger or aggression. Growls produced as serious
warnings will likely be low-pitched and come either from the chest or mouth,
with varying levels of bared teeth. Research has shown that dogs growl “honestly”
in serious encounters (the “size” of the growl accurately reflecting the size
and aggression-level of the dog), but they show more variability in their
growling when they play. Even when dogs growl during play, it almost never
leads to fighting (less than 2 percent of the time).7 Dogs can reliably distinguish
between a prerecorded “food growl” and a “stranger growl” and respond appropriately.8
Whatever else growling may mean, it clearly can be used as a
serious warning or signal of potential aggression, so we need to pay very close
attention to the rest of a dog’s body language when a dog growls. Humans are
not always very skilled at reading the intention of dog growls, though people
with more experience around dogs are better at distinguishing between playful
and aggressive growls, and women appear to do better than men.9 As with all the senses, it’s
important to become dog literate and learn as much as you can about your dog’s
growls. Along with a “bark ethogram,” consider also making a “growl ethogram”
for your dog.
WHINING
AND WHIMPERING: A CALL FOR HELP
Two other common types of vocalization are whimpering and whining.
These are distinct vocal communication patterns, although they are sometimes
hard to distinguish and many people lump them together as “crying.” Whining
tends to be louder and higher-pitched, while whimpering is quieter and lower.
Whimpering usually means that a dog isn’t feeling well and is sick, nervous, or
in pain. The communicative function of whining is not as clear.
A 2017 study on the relationship between dog
vocalizations and separation-related anxiety is a good example of the kind of
research we need to better understand and help our dogs. Excessive barking is
typically considered one of the main symptoms of separation-related disorder
(SRD) in family dogs, but in this study, Peter Pongracz and his colleagues wanted
to confirm whether dogs with separation anxiety vocalize their distress through
barking, through whining, or by using both vocalizations. Pongracz’s team
found, contrary to popular belief, that dogs with separation anxiety were more likely
to whine than to bark, particularly at the departure of their human, and that “early
onset and abundance of whining may serve as a reliable tool for diagnosing SRD.”
Whines and barks likely reflect different inner states. Another interesting finding
from Pongracz’s study was that a dog’s age was the most influential factor in
determining onset and abundance of barks during a short separation. Younger
dogs barked sooner and more than older dogs.10
One common myth about “crying” in dogs is that dogs always
whimper when they are in pain. While it is true that dogs in pain will
sometimes whimper, they don’t always vocalize their distress. A lack of
whimpering does not mean a dog isn’t in pain, since sometimes dogs only whimper
when pain has progressed to an intolerable level. At that point, just as in
humans, the cause of the pain has often progressed to a point where it is more
difficult to treat. With any injury or medical problem, the ideal is to notice
pain early and address the cause quickly with appropriate care or medications. There
are two lessons here: 1) If your dog is whimpering, it’s possible that
something is seriously wrong, so please seek the advice of a veterinarian; and 2)
don’t rely on vocalizations alone to determine whether your dog is
uncomfortable. Be sensitive to other behavioral cues, such as body posture and mobility,
and investigate any suspected problems right away.
BABY
TALK AND YOUR DOG
Nearly everyone has either done it or seen it done with a
dog. Someone kneels down, vigorously rubs a dog’s face and head, and starts
cooing and babbling: “What a sweet boy! Aren’t you a sweet boy? Look at those
sweet little paws! Who loves their baby, huh?” Dogs often feel like furry,
excitable children, and so we use “baby talk” with them, or as scientists call
it, “infant-directed speech . . . characterized by higher and more variable
pitch, slower tempo and clearer articulation of vowels than in speech addressed
to adults.”11
Is this a problem? Do dogs like it or care, or do they
simply tolerate it because they have no choice? And why exactly do we engage in
this bizarre behavior?
A study published in 2017 tried to shed some light on
pet-directed speech. The researchers learned that although people are more
likely to use baby talk with young puppies, they also consistently use this
speech pattern with older dogs. For their part, young puppies were more drawn
to baby talk than normal human speech, while older dogs seemed to ignore it.12
Thus, with dogs, it seems like we sometimes prefer to treat
them like children, no matter how old and mature they are. Does baby talk harm
dogs? Probably not in itself. Since it nearly always expresses our affection,
many dogs probably enjoy it to one degree or another. Then again, older and
other dogs may find it grating and confusing, much like human adults would if
spoken to that way. Observe your own dog to see what their reaction is, if
anything, to this type of speech.
However, animal ethicists aren’t so keen on baby talk
because they say it may reinforce a tendency to “infantilize” dogs and ignore
their intelligence and agency as individual beings with specific, dog-related
needs, such as the need to run free with other dogs. Similar to when people
dress up dogs in pink tutus or tartan sweaters, baby talk may encourage people
to treat dogs like toys or dolls, as unaware objects to play with, rather than
as subjective, sentient individuals.
TURN
DOWN THE VOLUME: PROTECT YOUR DOG’S HEARING
With the senses of smell and taste, we’ve discussed how
sensory deprivation can be a serious freedom inhibitor. The opposite is more
often true with hearing. Our world can at times be very loud and noisy, and
certain sounds can be very distressing to our canine companions, so an
important freedom enhancer is to respect a dog’s need for quiet and to avoid
auditory overload. We might like to turn AC/DC or Spinal Tap up to eleven, but
it is likely that screeching, feedback-filled rock music is actually painful to
a dog’s ear. If you like to play loud music — or if you do anything that
creates very loud, high-pitched noise, like running a vacuum cleaner or using power
tools — always make sure your dog has a place to go that is protected from the
sound.
Above all, pay attention to a dog’s behavior for signs that an
environment is too painfully noisy for them, for whatever reason. For instance,
Jessica once attended a summer Gin Blossoms concert at an outdoor venue in Fort
Collins, Colorado. In theory, it was an ideal venue to bring a dog, and people
were spread out on blankets and folding chairs in the grass. However, perhaps
because the concert was outdoors, the sound was turned up so loud that the
music was actually distorted, and Jessica had to cover her ears with her hands and
leave early because the sound was physically painful. She wasn’t alone. About
fifteen feet away from her was a couple with their dog, who was clearly
agitated, with his ears pulled back, tail down, and panting. His owners seemed
totally oblivious to the dog’s discomfort and showed no intentions of leaving.
Just as with people, it’s also likely that dogs can suffer permanent
damage and hearing loss from long-term exposure to extremely loud noises. There
has been no research into noise-related canine hearing loss, but plenty of
research confirms the effects on human hearing, and there’s no reason to think
that a dog’s ears are any less sensitive to damage. It’s well known that
hunting dogs can experience noise-induced hearing loss. Even the sound of a
single gunshot or explosion, if it occurs too close to a dog, can rupture the
eardrum or damage the inner ear. Further, ear infections can also cause permanent
hearing loss if not treated properly.
We owe it to our dogs to pay close attention to all the sounds
we expose them to and to do what we can to protect their long-term health.
However, perhaps the easiest hearing-related freedom enhancer you can provide
for your dog is to silence their dog tag. If dogs could talk, that might be
their number-one noise complaint. The constant jingling of the tag on their
collar gets in the way of listening to the world around them, particularly when
they are walking, running, or playing, and this keeps them from fully using
their acute sense of hearing to experience their surroundings. Tag silencers —
little neoprene covers that hold the tags together — are a cheap intervention
that will be greatly appreciated by your dog.
BE
SENSITIVE TO NOISE PHOBIAS
Many dog guardians know that certain sounds send their
canine companion into a tizzy fit. Some of the common culprits are fireworks,
gun sounds, and thunder. Indeed, studies suggest that nearly half, and perhaps
as many as three-fourths, of all family dogs are afraid of certain noises and
will show at least one behavioral sign of fear when exposed to them.13 These behavioral signs
include trembling, shaking, panting, salivating, hiding, and peeing or pooping
in the house. These fear responses are often called noise phobias, particularly
when the fear is related to a specific stimulus (such as a thunderstorm) and
when the behavioral response is extreme, such as scratching through a wooden
door trying to escape.
People may chuckle when they pop Bubble Wrap and their dog
trembles in fright, but noise phobias are no laughing matter. The trembling is
a sign of acute stress, and stress, as we know, is bad for your health. When
people get genuinely scared, they sometimes joke that it “just took a year off
my life!” Well, there is some truth to this, and we should take these fears
seriously. Our dogs deserve it.
To help reduce the chance that noise phobias will develop, we
can avoid exposing puppies to frightening sounds, and we can socialize puppies to
a wide variety of sounds. There’s some evidence that early exposure to a
frightening sound increases the risk of developing a related phobia, so as much
as possible, protect puppies from sudden or loud noises. Then, some people also
find that gradual desensitization to a scary sound can help prevent phobias
and, in some cases, help a dog move past their fears. As part of their puppy
socialization classes, the Humane Society of Boulder Valley (Colorado) includes
a gradual exposure to the sound of fireworks. A very soft recording of
fireworks popping is played in the background while the puppies are given a
constant stream of treats and praise. Each week the volume is increased just a
bit. The puppies don’t even notice the fireworks because they are so interested
in getting treats and playing with the other puppies.
Despite these efforts, dogs may still develop aversions to
certain sounds, and we must do our best to protect our friends from them. In
addition, noise sensitivity can be an indicator of pain, so when dogs show fear
or anxiety with loud noises, a visit to the veterinarian may be in order.14 In extreme cases, dogs with
noise phobias may need to see a behavioral specialist. Prescription medications
may help relieve anxiety in some dogs, and they could be used prophylactically
in situations where people cannot control the source of a noise, such as
thunderstorms and July Fourth fireworks.15
DOGS
NEED YOU, NOT THE RADIO
Sometimes
when a dog must be left alone for long periods of time, people turn on the TV
or radio, hoping that this will comfort or “entertain” the dog the way it might
a person. However, this may not actually be doing a dog any favors. It’s unlikely
that television images — even of jumping squirrels — music, or an audiobook
will be inherently interesting to them. If anything, the noise of a TV or radio
might interfere with a dog’s ability to hear outside sounds, which might be more
important. Most dogs consider it a vital part of their job to protect their
family and their home, so they may prefer to spend their day listening to “natural”
sounds from outside, which are likely more interesting, stimulating, and
enriching.
Leaving
a radio on all day won’t hurt a dog (unless the volume is too loud), and
indeed, some dog trainers and veterinarians report that certain kinds of music
and recorded sounds can have a calming effect and may have some application in
treating separation anxiety and noise phobias.16
But all in all, TV,
radio, and music aren’t substitutes for human interaction. The best treatment
for separation anxiety, loneliness, and boredom is to not leave a dog alone for
long periods of time.
by Marc Bekoff and Jessica Pierce.
Note
1.
Beth McCormick, “Fido Can Hear You, but Is He Really Listening?” Starkey
Hearing Technologies, November 1, 2017, https://www.starkey.com/blog/2017/11/can-my-dog-understand-me.
2.
George M. Strain, “How Well Do Dogs and Other Animals Hear?” Deafness in Dogs
& Cats (Louisiana State University), last updated April 10, 2017, https://www.lsu.edu/deafness/hearingrange.html.
3.
P. R. Simonet, M. Murphy, and A. Lance, “Laughing Dog: Vocalizations of
Domestic Dogs during Play Encounters,” paper presented at the meeting of the
Animal Behavior Society, Corvallis, OR, 2001.
4.
A. Andics et al., “Neural Mechanisms for Lexical Processing in Dogs,” Science
353
(September 2016):
1030–32, http://science.sciencemag.org/content/353/6303/1030.
5.
Dorit Feddersen-Petersen, “Communication — Vocal: Communication in Dogs and
Wolves,” in Encyclopedia of Animal Behavior, ed. Marc Bekoff
(Westport, CT: Greenwood Press, 2004), 385–94.
6.
Aimee Green, “Owners Must Surgically ‘Debark’ Loud Dogs, Court Rules,” Oregonian,
August 31,
2017,
http://www.oregonlive.com/pacific-northwest-news/index.ssf/2017/08/owners_must_surgically_debark.html.
7.
Bekoff, “A Dog Companion’s Guide,” chap. 9 in Canine Confidential.
8.
Tamás Faragó, “Dog (Canis familiaris) Growls as
Communicative Signals” (PhD thesis, Eötvös Loránd University, Budapest, 2011), http://teo.elte.hu/minosites/ertekezes2011/farago_t.pdf.
9.
Tamás Farago et al., “Dog Growls Express Various Contextual and Affective
Content for Human Listeners,” Royal Society Open Science 4 (May 17, 2017): 170134, doi: 10.1098/rsos.170134.
10.
Peter Pongracz et al., “Should I Whine or Should I Bark?: Qualitative and
Quantitative Differences between the Vocalizations of Dogs with and without
Separation-Related Symptoms,” Applied Animal Behaviour Science 196 (November 2017): 61–68, doi: 10.1016/j.applanim.2017.07.002.
11.
Tobey Ben-Aderet et al., “Dog-Directed Speech: Why Do We Use It and Do Dogs Pay
Attention to It?” Proceedings of the Royal Society B 284 (January 11, 2017), http://rspb.royalsocietypublishing.org/content/284/1846/20162429.
12.
Ibid.
13.
Emily Blackwell, John Bradshaw, and Rachel Casey, “Fear Responses to Noises in
Domestic Dogs: Prevalence, Risk Factors, and Cooccurrence with Other Fear
Related Behaviour,” Applied Animal Behaviour Science 145 (2013): 15–25, https://www.appliedanimalbehaviour.com/article/s0168-1591(12)00367-x/abstract.
See also Katriina Tiira, Sini Sulkama, and Hannes Lohi, “Prevalence, Comorbidity,
and Behavioral Variation in Canine Anxiety,” Journal of Veterinary Behavior 16 (2016): 36–44, https://pdfs.semanticscholar.org/a3de/432e01cbfbc60c17a662219d6262344b2451.pdf.
14.
“Dogs with Noise Sensitivity Should Be Routinely Assessed for Pain by Vets,”
Phys-Org, March 20,
2018,
https://phys.org/news/2018-03-dogs-noise-sensitivity-routinely-pain.html.
15.
M. Korpivaara et al., “Dexmedetomidine Oromucosal Gel for Noise-Associated
Acute Anxiety and Fear in Dogs: A Randomised, Double-Blind, Placebo-Controlled
Clinical Study,” Veterinary Record 180, no. 14 (April 8, 2017), https://www.ncbi.nlm.nih.gov/pubmed/28213531.
16.
“Research,” iCalmPet, accessed September 8, 2018, https://icalmpet.com/about/music/research.
