What makes an aggressive dog, and how you can spot one

What makes an aggressive dog, and how you can spot one
Study suggests it's not so much the breed as the gender, training, origin and owner's age.

(HealthDay)—You see a Rottweiler standing next to a poodle and a Chihuahua. Which dog is most likely to bite you?

To answer that question, don't look at the dog, British researchers say. Instead, look at the owner standing beside it.

A dog's breed is only one of many factors that influence its capacity for , according to a new study published recently in the journal Applied Animal Behaviour Science.

More telling clues to aggression might be the age of the owner, the training the dog has received, the place the dog was obtained and the gender of the dog, the researchers found.

In addition, that are aggressive in one situation likely will not be aggressive in other situations. For example, a dog that might lash out on the street could be perfectly peaceful in its own back yard.

"Aggression is incredibly complex. It's going to be both situation-dependent and dependent on the history of both the people and the dog," said Stephen Zawistowski, science adviser to the American Society for the Prevention of Cruelty to Animals (ASPCA). "You can't just pick the breed of the dog and say somehow that will be predictive of whether the dog will be aggressive."

Zawistowski, who is also an adjunct professor of anthrozoology at Canisius College in Buffalo, N.Y., was not involved with the new study.

For the study, Rachel Casey, of the University of Bristol's School of Veterinary Sciences, and colleagues distributed about 15,000 questionnaires to dog owners regarding dog aggression toward people. About 4,000 were returned.

The researchers found that owners reported dog aggression toward unfamiliar people more often than aggression to family members.

Nearly 7 percent of owners said their dog barked, lunged, growled or actually bit unfamiliar people who came to their house. Meanwhile, 5 percent reported these aggressive behaviors when meeting people while out on walks. By comparison, only 3 percent of owners reported aggression toward family members.

The results showed that a majority of dogs were aggressive only in one of these three situations. A dog that would lunge at a strange person on the street was not likely to lunge when a strange person approached their house.

In breaking down factors associated with dog aggression, the researchers found much more than the dog's breed at work. For instance:

  • Dogs owned by people younger than 25 were nearly twice as likely to be aggressive than those owned by people older than 40.
  • Neutered male dogs were twice as likely to be aggressive as neutered female dogs. However, there was no significant difference in aggression risk between neutered and non-neutered males.
  • Dogs who attended puppy-training classes were about one and a half times less likely to be aggressive to strangers.
  • Dogs trained using punishment and negative reinforcement, however, were twice as likely to be aggressive to strangers and three times as likely to be aggressive to family members.
  • Dogs obtained from animal rescue and other sources were much more likely to be aggressive than those bought from a breeder.

"The origin of the dog was a significant factor in aggression toward family members," said Mary Burch, Canine Good Citizen director for the American Kennel Club. "There was a 2.6 times increased risk in dogs obtained from rescue centers, and a 1.8 times increased risk from a combined category of 'other' sources, including pet shops and Internet sites, as compared to those obtained directly from breeders."

A lot of dog aggression is spurred by fear and anxiety, Zawistowski said. To avoid having an aggressive dog, he said, owners should properly socialize their pups by doing the following:

  • Leaving puppies with their litter until 8 weeks old, so they learn how to be social with other dogs.
  • Taking them to puppy kindergarten classes before 16 weeks old, so they become comfortable with other people and dogs.
  • Engaging them in positive-reinforcement training that teaches them things such as not jumping on people or pulling on a leash.

Older dogs that suddenly become aggressive might be experiencing pain due to an ailment. "If you're looking at a 6- or 7-year-old dog that's starting to be aggressive, you might want to look at whether the dog is starting to have some arthritis," Zawistowski said.

If you're worried that an unfamiliar dog might become aggressive toward you, you should pay attention to its body language, Burch said.

"Some pre-aggression behaviors are a direct stare, stiff posture, hackles up, ears or lips pulled back, baring teeth, growling, barking, lunging and snapping," she said. "Barking alone should not always be defined as aggressive behavior."

Burch criticized the British study for including barking as an .

"It can be problematic for barking to be considered 'aggression' because barking can have multiple functions," she said, noting that dogs also bark to alert owners or to signal that they need something. "In my opinion, this overly broad definition, which includes barking, skews the data to show that there is an aggression problem in the U.K."

Explore further

How common is aggression in UK dogs?

More information: For more about dog aggression, visit the ASPCA.
Journal information: Applied Animal Behaviour Science

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Citation: What makes an aggressive dog, and how you can spot one (2014, February 28) retrieved 14 October 2019 from https://phys.org/news/2014-02-aggressive-dog.html
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User comments

Mar 02, 2014
1) Which dog is un-muzzled ?

2) Does the dog still have a tail ?

3) Ask, 'Is your dog a good sniffer ?'

Mar 04, 2014
"Dogs trained using punishment and negative reinforcement, however, were twice as likely to be aggressive to strangers and three times as likely to be aggressive to family members."

Might be interesting to do such a study on people as well ...

Mar 04, 2014
Garbage data. Yes, owners impact how dogs act. No, there is absolutely no relevance between breeders and safety, compared to shelter animals. It's 100% how the animal is trained, raised, and treated. What a joke to pin it on where the animal is acquired. Breeder organizations likely behind this study.

Mar 04, 2014
@hiddenbrad, I don't think it's fair to say the study is garbage. You say 'It's 100% how the animal is trainged, raised and treated,' and you're right. But the catch is, that training and treatment starts from day 1. Shelter/rescue dogs aren't 'bad dogs,' but they are more likely to have experienced some form of mistreatment or neglect. Which doesn't mean they shouldn't be adopted, but it means that adoptive pet owners will likely need to work a bit harder to properly train and socialise their dogs. And unfortunately, many dog owners don't know how to do that.

Mar 04, 2014
@alrmac, you are exactly right. And not only direct abuse, or abusive neglect, but the sort of benign neglect caused by people who don't know, or don't care about early and consistent handling and socialization. It's not that random source dogs are "bad dogs", but overcoming that lack of adequate early handling and socialization often presents significant challenges, especially to the sort of young, idealistic, inexperienced new dog owners for whom "rescue" is now a pseudo religion. The same sort of folks tend to believe that random source dogs must be more "grateful" and "loving" than purpose-bred dogs, and they often can't understand why their "adopted" dog isn't a canine model of excellent decorum, so they excuse these behaviors by crying that he or she "must have been abused", or "used as a bait dog".
It's not junk data. It's absolutely apparent, excessive idealism meeting lack of preparation meeting the absurd new culture of demonizing the people who do things right from day one.

Mar 04, 2014
IOW, @hiddenbrad also has it exactly right that "It's 100% how the animal is trained, raised, and treated", and that dogs brought into the world accidentally or mindlessly by people who don't care how the dog is "trained, raised, and treated" are the overwhelming majority of dogs who end up at shelters. Mostly because they were purchased by people who also didn't care how they were trained, raised, and treated, then dumped them on the shelter system as adolescents. Overcoming that lack of foundational handling is, or should be, a serious consideration when choosing especially a first dog. It's truly unfortunate that we have allowed that issue to be swept under the rug by the anti-breeder brigade.

Mar 10, 2014
@hiddenbrad - you are right (except the part about it being funded by breeders). The author does acknowledge contributions by Blue Cross, Dogs Trust, Kennel Club and RSPCA. The review posted by Mr. Thompson is very misleading, and in some cases flat out wrong. After reading the actual study from the Applied Animal Behaviour Science journal, the study identified some common characteristics of owners and dogs that were risk factors for aggression. Protective factors were: early socialization, continued socialization, and positive treatment. Aggressive behaviors were situation specific, indicating they were likely learned not breed specific. This statement: "Dogs obtained from animal rescue and other sources were much more likely to be aggressive than those bought from a breeder" is flat our wrong and was not stated in the study. The statistics were presented as odds ratios, so Mr. Thompson may have misunderstood how to interpret odds ratios or was getting info second hand.

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