Why is President Biden’s dog attacking Secret Service personnel? There could be many reasons, specialists say.

Following reports that President Joe Biden’s dog Commander bit Secret Service personnel at least 10 times over a four-month span, dog experts say there are a multitude of reasons why a German shepherd might exhibit such aggressive behavior.

Laney Nee, an animal behavior manager for the Animal Rescue League of Boston and a certified professional dog trainer, said biting is generally a means of communication for dogs.

“Dogs don’t necessarily want to become aggressive,” she said. “There will be a real good reason for it.”

So when a dog bites someone, what are they trying to convey?

“They can’t speak, like you and I can,” Nee said. “So you want to get to the source of it. Every situation is different, as is every dog.”

Aggressive behavior in dogs “is like a ladder,” Nee said. Their level of aggression can ramp up “if they’re put in situations where they’re not being listened to.”

In a stressful situation, a dog might pull its ears back. Then it might bark and back off. Or it might bark and move forward. Then it might show its teeth or snap at the air, she said.

All are signs that the dog is uncomfortable, she said.

“It could be anything from fear to stress,” she said.

Exposing the dog to different training methods from different people can lead to confusion, which may also cause aggressive behavior.

The bottom line is that owners and handlers need to be aware of the dog’s body language and try to determine what it means.

For example, if a dog is afraid of living in a city and being around a lot of people, it might make sense to move the pet to a more suitable place.

“If it’s too much, it’s too much,” she said.

For an animal bred to be territorial and protective, it’s easy to see how the bustling atmosphere of the White House could be difficult, said Dr. Terri Bright, who leads the behavior services department at the MSPCA’s Angell Animal Medical Center.

“It sounds like a chaotic existence, where there’s always someone coming around a corner who you don’t know,” Bright said. “That kind of unpredictable environment is tough on a dog.”

Secret Service agents are assigned to protect the president, but the dog has territorial instincts and may exhibit aggressive behavior toward strangers who appear in “places they deem to be their territory,” Bright said.

“They may be Secret Service, but the dog says, ‘Nuh-uh, this is my territory,’” Bright said.

One way to prevent negative encounters is to introduce the dog to people away from its normal territory, Bright said.

If that doesn’t work, or isn’t an option, the dog should be placed in a different area with toys and treats, and maybe a white noise machine, Bright said.

“If there’s any risk at all, the dog should be segregated,” she said. “If the dog won’t settle, or if they’re targeting a person, before anyone comes over, the dog should be in another room.”

Bright cited one media report of a time when Commander was standing on the landing of a staircase and barked at a Secret Service officer. The officer grabbed a chair and held it up in a protective manner, which “exacerbated” the situation, she said.

In an ideal world, the pet might have separate living quarters and have strangers “stay out of there,” Bright said. “But I bet that’s not possible there.”

Have questions about your pet’s behavior? The Animal Rescue League of Boston offers a free pet behavior helpline — for any species of animal — that can be reached at 617-226-5666.