Do Dogs Get More Aggressive as they Age?

Dogs are considered man’s best friend for good reason. They are loyal, intelligent and make great companions.

But as dogs age, they can become more aggressive. This is often due to a decline in cognitive function and can be a difficult phase for both the dog and his owner.

There are ways to help manage an ageing dog’s aggression, but it is important to understand the root of the problem and take steps to address it.

Causes of aggression in older dogs

As dogs age, they can become aggressive for a number of reasons

Physical changes

Dogs may become more irritable as they age due to physical changes such as hearing and vision loss. Dogs with these conditions often become more anxious and are more likely to be aggressive towards other dogs.  In dogs with hearing loss, the dog may hear or see things that cause anxiety such as someone walking down the street and react in fear to it. Dogs with visual impairment may see things or people that cause anxiety.  In either case, the dog becomes more likely to act aggressively in response to these fears.

Mental Changes

As dogs age, they may become confused or forgetful, leading to frustration and potential aggression. Also, the dog may become stressed just from seeing other people.

Changes in the Environment

Dogs can become aggressive for a number of reasons, including changes in their environment. For example, a new dog in the neighborhood may cause a dog to become territorial and aggressive. Dogs that live with young children may become more aggressive as the number of children in the house increases.

Lack of Socialisation

Dogs are social animals and without proper socialisation they can become aggressive. Dogs do not naturally become more aggressive as they age, but rather, their aggression can be brought on by a lack of socialisation or improper training. It is important to ensure that your dog has plenty of opportunities to interact with other dogs and people, as this will help to prevent any unwanted behaviours from developing.


Older dogs can become aggressive due to medication. The medication, while effective in treating other conditions, can trigger aggressions in older dogs. This is a particular problem because many dog owners believe that their elderly pet is just “getting grumpy” and may not realize that the source of the problem is the medication.

If an older dog starts displaying signs of aggression, it is important to take him or her to the veterinarian to rule out any medical issues as potential causes. If it is determined that the aggressions are being caused by medication, then there may be ways to alter the dosage or switch to a different medication that does not produce the same side effects.

Cushing’s Syndrome

As dogs age, they can sometimes become more aggressive. This is often due to a condition called Cushing’s Syndrome, which is caused by an overproduction of the hormone cortisol. Dogs with Cushing’s Syndrome may become more irritable, restless, and aggressive. There is no cure for Cushing’s Syndrome, but there are treatments available that can help manage the condition. If your dog begins to exhibit signs of aggression, it is important to take him to the vet for an evaluation.

Types of Aggressive Behavior Your Elderly Dog May Exhibit

There are several different types of aggression that dogs can exhibit. As your elderly dog enters their golden years, you may begin to notice changes in their behavior.

Social Aggression

Aggression can manifest itself in several ways, such as growling at people or other dogs, snapping, or even biting. It’s important to be aware of the different types of aggression and how to handle them should they occur. 

Territorial Aggression

One type of aggression is territorial aggression. This often happens when a dog perceives that someone or something is encroaching on their territory. They may bark and snap at people or other animals who enter their space. It’s important to remember that this type of aggression is usually motivated by fear, so you should avoid yelling or scaring the dog. Instead, try calmly asserting your dominance and keeping them away from the object or person they’re guarding. 

Possessive Aggression

Another type of aggression is possessive aggression. Possessive aggression is a type of aggression that is seen in older dogs. It is marked by the dog’s unwillingness to share objects or food with others, and can result in serious fights.

Dogs who are prone to possessive aggression may become agitated when someone comes near them while they are eating or playing with a toy. If left unchecked, this type of aggression can lead to serious behavioral problems in the dog.

How to treat an aggressive dog

Dogs that are aggressive can be a handful and present a danger to both themselves and others. If you have an aggressive dog, it’s important to create and implement a treatment plan as soon as possible. The following tips will help you get started:

  1. Start by assessing the cause of the aggression. Dogs can become aggressive for many reasons, such as fear, territoriality, or dominance. Once you know what’s causing the behavior, you can start working on a treatment plan that targets that issue.
  2. Try to keep your dog calm and relaxed. This may involve using obedience commands or treats to reward good behavior. If your dog is anxious or stressed, it will be more difficult to treat the aggression.
  3. Be firm and consistent. This will help with the dog’s confidence and trust in you, which is vital to the treatment process.
  4. Ensure that your dog is safe from any potential threats.

In Emergency Situations

If you are faced with an aggressive dog, there are several things you can do to diffuse the situation.

First, try to remain calm and avoid eye contact with the dog. Do not run or scream, as this may provoke the dog further. Instead, back away slowly and allow the dog plenty of space. If possible, try to put an object between you and the dog (a backpack or a fence, for example).

If the aggression continues, speak in a loud, firm voice and firmly tell the dog to “stop.” If all else fails and you feel that your safety is in danger, use whatever means necessary to protect yourself.

Closing Thoughts

While all dogs can become aggressive at any age, there is some evidence that dogs may become more aggressive as they age. However, there are many other factors that contribute to canine aggression, so it is important to take all of these into account to help reduce the causes and severity of aggression in your ageing dog.

If you are really concerned, you should consult a dog trainer who will be able to help reduce the aggression in your elderly dog.

An image showing Shonoff, a once fearful and aggressive rescued dog, now radiating happiness

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