Written by Dr. Marcelle Landestoy, DVM

The Cavalier King Charles Spaniel is an adorable toy breed with charming eyes and a friendly personality.
However, small dogs sometimes get a bad reputation for being overly aggressive, which might make you wonder if the Cav’s looks are deceiving and if the breed isn’t as friendly as it seems after all.
Cavalier King Charles Spaniels typically do not showcase aggressive behavior. They were bred as companion animals, so they’re very affectionate and crave attention. When socialized well, they don’t exhibit signs of aggression. They only bite if they’re looking for attention or feel stressed.
Let’s take a deeper look into this lovely breed and see if there’s any cause to worry when it comes to aggression.
Are They Aggressive to Humans?
Cavalier King Charles Spaniels are not aggressive to humans. These dogs were bred for companionship, so they’re typically kind, playful, and sociable. Dog parents don’t have to worry about aggression in this breed. They only get aggressive if threatened or want to grab your attention.
The Cavalier King Charles Spaniel is a suitable breed for a family since we have bred them to be great companions and kind dogs that love to cuddle.
If they haven’t been abused and have been socialized correctly, they will get along great with humans.
Let’s see how well they’ll get along with the people around you.
Family Members
As affectionate dogs, Cavs can get on well with anyone in the family.
Their playful nature and love of cuddling make them excellent pets for all family members.
They can also thrive in the city and the countryside, so they’re a great choice if you have to move often.
Here’s how well they get on with specific family members.
Babies
As clever and loving dogs, Cavs typically do not exhibit aggression toward babies.
Of course, as a playful breed, there isn’t much they can do with babies, but you can be sure they’ll be nice to them.

Toddlers
Cavs can get along great with toddlers. Their playful energy will probably match the toddler’s, and they can become great playmates.
They won’t get aggressive, but you must explain the boundaries to your toddler and prevent them from stressing or hurting the dog so they don’t bite in self-defense.
Older Kids
Older kids can also be good friends with the breed. They’re not likely to put the dog in a stressful situation and will still retain a lot of energy needed to keep up with one.
If both parties like walks and cuddles, there will be no problems whatsoever.
Adults
Cavaliers are also great companions for adults. However, they require an active adult with enough time to dedicate to their dogs.
Otherwise, the dog may get bored and frustrated, which may cause them to bite their parents to get attention.
Strangers
If you’re a parent of a Cavalier, you don’t need to worry about them getting aggressive with strangers.
They are more likely to come and greet strangers, especially if you’re around. Let’s see how they’ll deal with them.
In Your Home
Guests
Your Cav will most likely want to get to know your guests and become friends.
They’re not likely to get aggressive, and they’re more likely to beg for cuddles and scratches.
However, sometimes, they can get overly friendly and get in your guest’s way.

Intruders
When faced with an intruder, Cavs can get aggressive to protect their territory, babies, and parents.
However, you shouldn’t rely on them as guard dogs due to their friendliness, which might make them see intruders as potential friends.
Outside Your Home
A well-trained Cavalier will retain their good manners even outside your home.
They’ll be kind to strangers and just as affectionate as usual.
Unless something stresses them out, they’ll be well-behaved and happy to meet new people and dogs.
Are They Aggressive to Other Animals?
Cavalier King Charles Spaniels are not aggressive to other animals. They’re tolerant and will get along nicely with your other pets. Very small pets may be an exception, as the dogs might see them as potential prey, so you should not leave them unsupervised with pets like rodents or lizards.
As a parent of a Cavalier King Charles Spaniel, you don’t have to worry about them getting aggressive with other animals.
Let’s examine how they will get along with your other pets and animals they might encounter outside.
Other Animals in Your Household
As very tolerant dogs, Cavs will be happy to be friends with your other pets, especially when it comes to common pets, such as cats or other dogs.
If they get to know your other pets early, they will grow friendly and won’t cause problems.
However, you might encounter some problems if you introduce them to your other pets at an older age.
Still, they can overcome their issues with time and persistence.
Things might be slightly different when it comes to small pets, such as hamsters, mice, rats, lizards, and similarly small animals.
They were bred not only as companions but also as sporting dogs.
This might make them see your small pets as prey rather than other pets, so you must be careful if you’re also a parent to such animals.
Animals They Encounter Outside

Cavaliers tend to be curious and friendly when faced with other animals outside.
They’re much more likely to come and say hi to other animals than to get aggressive.
This can only change if the other animal gets aggressive first, and the Cavalier has to go into self-defense mode.
Are Female or Male Cavalier King Charles Spaniels More Aggressive?
Male King Charles Spaniels tend to be more aggressive than their female counterparts. Females tend to be more independent and bond with and protect only their parents, while males are more family-oriented. Females are also a bit easier to train and better around kids.
Even though the breed is not generally aggressive, males tend to exhibit more aggression than females.
Males are also more stubborn, harder to train, and clumsier around kids.
Therefore, get a female if you’re looking for a dog that’ll be a better companion to your kids.
On the other hand, females are more independent and less clingy than males.
Therefore, males can make better lap dogs.
What Can Cause Aggressive Behavior?
Triggers that cause aggressive behavior in Cavalier King Charles Spaniels include: medical issues, self-defense, feeling stressed or anxious, and trying to get their parent’s attention.
If your Cav suddenly becomes aggressive, and you can’t pinpoint a reason, the behavior might point to underlying health problems.
This is usually followed by other symptoms, such as:
- Hair loss
- Weight gain
- Weight loss
- Lethargy
- Mood swings
In that case, it’s best to take your pet to the vet.

This can prevent these problems from escalating and getting more dangerous for your dog since there might be a serious problem, such as:
- Hypothyroidism
- Tumors
- Hydrocephalus
- Trauma
Apart from that, your Cav may bite you if they lack attention and can’t get it any other way.
You can easily prevent this by scheduling enough time for active play with your dog.
They can also get aggressive if they feel anxious or think there’s a threat to their puppies, parents, or territory.
In that case, you must find their anxiety’s root cause and remove it.
It’s essential to be there and reassure your dog that nothing will happen to them, and have patience if they seem scared and aggressive because of it.
For example, if your dog’s aggression seems to be triggered by the sound of a specific device, such as a vacuum cleaner, don’t use the device around your dog, or swap it for one that seems less triggering.
Or, if your dog feels anxious because you’ve moved recently, and they don’t like your new home, give them time to explore, get to know, and accept it as their territory.
Moving is stressful for humans and even more so for animals, as they might have a tough time understanding what’s going on.
If your Cavalier has puppies, be careful around them.
If your dog gets protective around them, it’s best to avoid touching them until they’ve grown a bit or until your pet brings them to you.
Otherwise, your Cavalier might see you as a threat and get aggressive.
Is Your Cavalier King Charles Spaniel Being Aggressive or Protective?
To determine whether your Cavalier King Charles Spaniel is being aggressive or protective, examine their body language. The behavior is protective if your Cavalier is defending their puppies or you. Regular aggression tends to be triggered by far more trivial causes.
Learn To Recognize the Signs That Your Dog Is About To Get Aggressive

There are a few signs that signal oncoming aggression in dogs:
- Low growling
- Preparing to lunge
- Keeping ears and tail upright
- Posturing
- Snapping jaws
There are a few types of dog aggressiveness, but the two most common types come in the form of dominance aggression and fear aggression.
A dominant-aggressive dog will produce a low growl while maintaining eye contact and preparing to lunge at the perceived threat.
Their ears will also be upright, and they might stiffen their tails and move them left to right.
If you see this behavior in your Cavalier, it’s important to restrain them and prevent them from attacking.
On the other hand, a dog who’s aggressive out of fear will exhibit completely different signs.
They’ll avoid eye contact and keep their head, and body low with their tail tucked between their legs.
In that scenario, touching them or taking something away from them might cause them to snap or attack.
In that case, it’s good to try and separate them from the other dog to de-escalate.
What To Do During an Aggressive Episode
If you see your Cavalier getting aggressive, the best course of action is to remove them from the situation.

Thankfully, they’re relatively small, so it’s not difficult to drag them away.
It’s even easier to pull off when the dog is on a leash.
Pull persistently and start walking, prompting your dog to follow you.
Picking them up and carrying them away is also an option, but it’s not the safest one since they might bite you if they’re particularly stressed.
The smartest thing to do is prevent this behavior. You can do this by:
- Encouraging and rewarding restraint and calmness.
- Avoiding overly arousing situations.
- Getting your Cavalier to meet mature dogs.
- Spaying/neutering your cavalier.
- Letting your dog socialize with other dogs.
- Treating them with kindness and respect.
When To Get Professional Help
If your Cavalier growls, barks, and snaps seemingly out of nowhere only on rare occasions while otherwise being affectionate and well-behaved, there is no cause for alarm.
Showing some signs of aggression from time to time is normal, even if we find it annoying.
The problem arises when your Cavalier consistently behaves aggressively without an apparent reason.
It’s especially alarming if some health problems are coupled with this, even if they’re minor.
In that situation, you must schedule an appointment with your veterinarian and let them have a look at your dog.
Chances are, there’s an underlying medical issue that frustrates your dog, and there’s no other way for them to get rid of the frustration.
In that situation, there’s no other way to get rid of aggression but to eliminate the underlying problem.

If the vet has examined your Cavalier and found no medical issues, then it’s best to visit a dog behavior expert.
They’ll examine your dog and try to grasp the root of the problem, after which your dog may enter a rehabilitation process to (re)socialize and learn how to manage stress, fear, and anxiety without aggression.
The rehabilitation process usually lasts a couple of weeks. It often requires that the dog spend some time at the rehabilitation center.
This allows the specialists to examine them, find the cause of their behavior, and start with the right training.
They will also work with you to equip you with the right tools so that you can continue the training at home.
Conclusion
Cavalier King Charles Spaniels are not an aggressive breed.
They’re generally friendly and crave human attention.
In the rare cases when they do get aggressive, it’s because of medical issues, stress, or a self-defense response.

References
- Sit Means Sit: How to Tell if a Dog is Being Aggressive
- Bubbly Pet: Male Vs. Female Cavalier King Charles Spaniel: Which Is Better?
- Spaniel King: Are Cavalier King Charles Spaniels Aggressive?
- Pumpkin: 15 Best Dog Breeds for Kids
- Canine Perspective Chicago: Cavalier King Charles Spaniel Training Profile
- Pet Plan: Cavalier King Charles Spaniel Facts & Advice
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Marcelle Landestoy Veterinary Hospital Director at UCE Dr. Marcelle is a general veterinarian with a Small Animal Medicine Specialty | Director of the UCE School of Veterinary Medicine | Certified by the International Veterinary Acupuncture Society |