When the garbage truck drives up to my house every week, my three little dogs can barely contain their excitement. They bark and race from one window to the next. At one point, my chihuahua mix will throw back her head and release a dramatic howl.

It seems ridiculous to howl at a garbage collector. However, animal behavior researchers have learned howling is a vital form of communication among wolf packs. This behavior lingers among some domesticated dogs, and scientists are learning that dogs howl for many reasons. 

Why Do Wolves Howl?   

Wolves have many reasons for howling, and researchers have observed wolf packs happily howling in each other’s faces as a way to reinforce their group membership. In this sense, howling as a group is a team-building exercise.

Wolves howl daily. They might do it to demonstrate their attachment to others. Or they might howl while hunting as a pack. If a wolf is separated from their pack, it will howl and listen for the return howls to locate and reconnect with the others. When reunited, they typically howl again.

Howling is a contagious behavior; when a pack member starts, the others usually join in. Sometimes, researchers suspect these howls are to warn other wolves to keep out of their territory.

Howling is one of the many vocalizations that wolf pups learn within the first few weeks of life. Domesticated dogs are similar in that their puppies also learn vocalizations at just a few weeks of age. For some dogs, this can involve learning what it means to howl. 

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Do All Dogs Howl?

Scientists have found that not all dogs are into howling. In a 2023 study in Communications Biology, researchers observed 68 purebred dogs as they listened to recordings of wolf howls. The dogs were from 28 breeds, including 17 “ancient breeds” such as Alaskan malamute, Akita inu, Pekinese, Shiba Inu, Shih Tzu and Siberian husky. 

Along with their human, the participating dogs each walked into a room where cameras were set up to record. The researchers played a series of howling sounds from a speaker, followed by silence. They analyzed the video recordings for behavioral responses.

About 58 percent of the dogs responded to the recordings with some sort of vocalization. Dogs from ancient breeds were more likely to vocalize or howl than domestic dog breeds. Dogs from more modern breeds were more likely to bark. The authors hypothesized there was a lingering genetic relationship between the ancient breeds and wolves when it came to howling.

Older dogs in the study were more likely to howl than younger dogs. The authors noted a similarity with wolves as they tend to be more aggressive in defending their territory as they age.

However, the researchers questioned why all of these doggie participants — who came from a different social structure than wolves — would respond to wolf howling with their own howl. The researchers suspected the howling may have resulted from domesticated dogs’ working relationships with humans. Dogs have long pulled sleds, guarded property, hunted and herded. If they lost contact with their humans, these dogs might have turned to howling to reconnect. Thus, the social structure changed and gave new use for the behavior.

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Why Do Dogs Howl?

For some dogs, howling is a vocalization they turn to when left alone. They miss their pack and howl as if their humans might hear their cry, leave their full shopping cart, and hurry home.

In a 2013 study in the Journal of Veterinary Behavior, researchers found that dogs clinically diagnosed with anxiety were more likely to vocalize when left home alone than dogs without separation issues. The researchers recruited 30 dogs from a veterinary clinic who were not known to have anxiety and then set up video cameras in their homes. The humans were asked to turn on the recorders and leave for 90 minutes.

All but five of the dogs were given free roam of their house. Most spent their time doing “passive behaviors.” Some dogs showed signs of stress, and about 10 percent howled.

In a related study, 23 dogs with known anxiety issues were also recorded when left home alone. About 22 percent had some sort of vocalization, including howling, which typically occurred within 10 minutes of the owner leaving the house. The authors concluded that for some dogs, howling is a stress-related behavior that occurs when they find themselves home alone.   

Read More: What To Do If Your Pet Is Struggling With Anxiety

Is Howling Genetic?

For some dogs, it can be an inherited trait. In a 2022 study in Science, researchers compared doggy genetics with owner surveys about their behavior. People with certain breeds like beagles, bloodhounds and huskies were more likely to report their dog was a howler. The scientists saw breed type as a predictor of whether a dog was likely to howl.

But my chocolate-brown chihuahua (mixed with some dachshund) isn’t an “ancient breed” or a breed type known for howling. So why is she howling at the garbage collector each week?

The Science study found that dogs are unique individuals, and breed types can only explain so much. Researchers aren’t currently able to get down to the chromosomal level to see which behaviors are shared among dogs with specific genes.

My chihuahua apparently inherited some sort of howling gene, and with two other dogs in the house, she just might be working with her pack to make her territory known and protect her turf from… the garbage collector.

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