April 2, 2026, 10:48 am | Read time: 4 minutes

We Misinterpret Signals

“In the rarest cases does a dog actually bite out of nowhere,” says dog trainer Katharina Marioth. From her perspective, most incidents are preceded by a series of signals—only these are often not recognized or misinterpreted by people.

At the same time, she warns not to underestimate possible medical causes. Hormonal disorders such as thyroid problems, certain heart diseases, or even pain in the musculoskeletal system can cause dogs to suddenly react aggressively. “Especially if behavior seems to change abruptly, it should definitely be checked by a veterinarian,” says Marioth.

It’s Often About Resources

Apart from such medical reasons, the cause of many conflicts lies in everyday life itself. Especially in direct cohabitation, misunderstandings occur. “We often pay too little attention to the needs and communication style of our dogs,” explains the trainer.

Critical situations often arise around so-called resources—such as food, toys, or even the dog’s resting place. Even caregivers can represent a resource from the dog’s perspective. It’s no coincidence that many incidents happen in or near the basket.

Typical Warning Signs Before a Dog Bites

Dogs often send clear warning signals—only these are not always recognized as such. A classic example: The dog is lying in its basket, someone approaches, and the animal turns onto its back. What many interpret as an invitation to pet is actually a calming signal, explains Marioth.

If the desired distance is not maintained, further signs follow: The dog briefly closes its mouth, smacks its lips, looks away, or lays its ears back. The so-called “whale eye,” where a white triangle in the eye becomes visible, can also indicate that the dog feels uncomfortable.

It’s especially important to take growling seriously. “It’s basically the yellow light of the traffic signal,” says Marioth. It used to be common to train dogs not to growl—a fatal mistake. Because this removes an important warning stage. “Then it can happen that the dog jumps directly from green to red,” meaning it bites without warning.

More on the topic

Dog Trainer Explains Why Many Dogs Allegedly Bite Suddenly

Dog Trainer Explains When Dogs “Play”–What Really Lies Behind Wild Running and Chasing

Why Dogs Seem to Bite “Out of Nowhere”

Still, there are situations where an attack seems completely surprising to people. According to Marioth, this is often because dogs have already gone through several strategies unsuccessfully. Basically, they have various ways to deal with stress: avoid, calm, freeze—and only attack as a last resort.

If a dog has no escape option, such as being cornered or pressured in its basket, and its previous signals are ignored, it eventually has only the last option left. “From its perspective, it has already tried everything else,” says the trainer.

How to Act After a Bite

If a bite or even a snap occurs, the situation is usually already resolved for the dog. Because typically, the person automatically backs away—exactly what the dog wanted to achieve. Scolding doesn’t help at this moment, emphasizes Marioth. It’s more sensible to calmly analyze the situation afterward: Where was the dog? Was it defending something? Was it pressured? Was there an opportunity to avoid?

Based on this, professional support should be sought as quickly as possible. “This is not a case to solve alone,” says Marioth. It’s not just about training but also about rebuilding trust between humans and dogs. Because such an incident often leaves marks—many owners feel insecure or tense in their own homes afterward.

The good news: In many cases, behavior can be effectively addressed. However, the prerequisite is understanding the causes—and recognizing the often subtle signals of dogs early on.