Vol. 17, No. 03 – Nov 1 – Nov 14, 2023 – The Pet Page

by Coco Lederhouse

Augusto DeOliveira “The Dog Daddy”, has gone viral on social media for his ability to control dogs. However, numerous behavioral science organizations, including the American College of Veterinary Behaviorists (ACVB), are warning owners that aversive training methods can be dangerous.

His dog training practices have caught the attention of concerned animal welfare groups, trainers, veterinary behaviorists, and pet owners. On September 13, the American College of Veterinary Behaviorists (ACVB) issued a statement expressing serious concerns regarding DeOliveira’s training practices and warning of the damaging effects that his methods could have on dogs.

“The training methods we see in the videos are using physical force or correction,” said Dr. Kelly Ballantyne, president of the ACVB and medical director at Insight Animal Behavior Services in Chicago. While aversive techniques may appear to stop a “bad” behavior, she explained that the effectiveness of the intervention isn’t determined by what happens in the moment, but if the behavior is changed over time. The American Veterinary Society of Animal Behavior issued a position statement in 2021 on humane dog training that advises against aversive training methods.

Several other organizations, including the Animal Behaviour and Training Council and the Royal Society for the Prevention of Cruelty to Animals raised concerns about DeOliveira’s group training sessions in London earlier this summer.

Similarly, the Association of Professional Dog Trainers and the Pet Professional Guild Australia issued a statement in response to DeOliveira’s training techniques.

Both George and Dr. Ballantyne warned of trainers who use outdated language like “dominance” or “alpha.” Dominance theory, based on the perceived dynamics of a wolfpack, has been debunked even in wolves,

”How do cats purr? New finding challenges long-held assumptions.

Fibrous “pads” in the vocal cords allow cats to make low-frequency sounds, which they don’t seem to consciously control.

One of the most delightful sounds to a cat lover is their feline friend’s rumbling noise when they get a little scritch behind the ears. Yet how cats produce their contented purrs has long been a mystery.

A new study may finally have the answer. Domestic cats possess “pads” embedded within their vocal cords, which add an extra layer of fatty tissue that allows them to vibrate at low frequencies, scientists report today in Current Biology. What’s more, the larynx of these animals doesn’t appear to need any input from the brain to produce such purring.

“Purring has historically had a complex, nonscientific explanation,” says Bonnie Beaver, a veterinary scientist at Texas A&M University who wasn’t involved in the study. Nonscientific, she says, because although scientists had devised various theories to resolve the mystery, few were ever tested. The new study, Beaver says, is a good step forward.

Domestic cats are small, with most weighing about 4.5 kilograms, and researchers had puzzled over how these animals manage to generate the low-frequency vocalizations—typically between 20 and 30 hertz (Hz)—involved in purring. Such frequencies are usually only observed in much larger animals, such as elephants, which have far longer vocal cords. And whereas big cats such as lions and tigers are capable of loud roars, domestic cats are only able to produce low-frequency purring.

Most mammal vocalizations, including other cat noises such as meowing and hissing, are produced in a similar way—a signal from the brain causes the vocal cords to press together, and the flow of air through the larynx causes the cords to knock against each other hundreds of times per second, producing sound. This process, known as flow-induced self-sustained oscillation, is a passive phenomenon: Once the vocal cords start to vibrate, no further neural input is required to keep them going.

But in the 1970s, scientists proposed that purring was different. The so-called active muscle contraction hypothesis holds that domestic cats actively contract and relax their laryngeal muscles about 30 times per second in order to purr. The idea, based on measurements of electrical activity in the laryngeal muscles in purring cats, caught on and has been a common explanation for cat purring ever since.

The new study challenges this.

The team was able to produce purring in all of the larynxes—a “great surprise,” says lead author Christian Herbst, a voice scientist who holds dual appointments at the University of Vienna and Shenandoah University. Without any active neural control, all eight larynges produced self-sustaining oscillations at frequencies between 25 and 30 Hz—suggesting purring doesn’t necessarily require active muscle contractions.

Looking at the anatomy more closely, Herbst and colleagues turned to unusual masses of fibrous tissue embedded in the cats’ vocal cords. Anatomists had noticed these masses before, but nobody knew what their function might be. It’s possible, Herbst says, that these “pads” increase the density of the vocal cords, causing them to vibrate more slowly and making it possible for cats to produce low-frequency sounds despite their relatively small size. Anatomically, he says, the process works similarly to “vocal fry”—a droning vibrato sometimes added to the ends of words—in human speech.

The new experiment instead suggests that purring, like meowing and hissing, is a passive phenomenon that plays out automatically after cats’ brains provide the initial signal to purr, the researchers conclude. That explanation “is much more in line with what we know about how vocalizations are produced in other vertebrates,” says Karen McComb, an expert in animal behavior and cognition at the University of Sussex who wasn’t involved in the study.

However, David Rice, a biomechanical engineer at Tulane University who has conducted research into the mechanics of cat purring, isn’t fully convinced. He says there’s no guarantee that living cats’ vocal cords behave the same way as the surgically removed cords from the study. Just looking at excised larynges, he says, is “akin to removing the mouthpiece from a wind instrument and analyzing its sounds in isolation.”

Every morning, weather permitting, a little before 8am, local senior citizen, Bobby, arrives with his folding chair and a pocket full of Milk Bone Soft and Chewies.  He knows each dog by name and they know they will each get one treat and a heartfelt pet for saying hello.  Each knowing dog will bound out of their “guardian’s”  (as Bobby calls them)  vehicle and race to their friend in the folding chair where they can greet each other eye-to-eye. Bobby truly enjoys starting each morning with dozens of “kisses”.  It is a joy to watch. 

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