How to Train Your Dog: A Size-Appropriate Guide

There are many benefits to owning a dog. Dogs provide companionship for the owner and encourage social interaction with other like-minded dog owners. But most people don’t consider the ease or difficulty of training a dog when they choose their dog. Many people ignore this important factor -- and when they do so, it can lead to owner dissatisfaction.

In 2025 an ELTE study of 5,000 dogs explored whether a dog’s ability to be trained was correlated with physical characteristics of the breed of the dog such as height, weight, and skull shape. The study asked owners of 48 different breeds of dogs about the physical and behavioral characteristics of their dog.

This study found that the size of the dog was one of the strongest predictors of a dog’s behavior. More specifically:

1. Undesirable behaviors become more common or pronounced as the size of the dog decreases.
2. As height increases, so does the dog’s trainability.
3. Long-skulled dogs (think Dachshunds or Italian Greyhounds) have higher rates of stranger-directed fear, barking persistently, and stealing food behaviors as the height and weight decrease.
4. Lighter dogs are especially likely to be reported as excitable, energetic, and hyperactive.
5. Urination/defecation when left alone, separation problems, attachment/attention-seeking, and begging are more prevalent in shorter breeds.

There are clear biological reasons for some of these findings. Small dogs are usually more fearful and excitable because everyone else in their environment seems to be 30 feet tall. This can create a default setting of fearfulness. And if you’re always in fight or flight mode, it can be difficult to learn to sit and stay like a good boy (or girl). Similarly, smaller dogs often have higher baseline arousal, which means that their default setting is…well, basically kinda anxious: alert, jumpy, quick to react, and easily startled.

The scientific reason for this?

Smaller dogs may be more difficult to train due to their excitability.

Source: Hillary Halliwell / Pexels

With smaller dogs, their size allows nerve impulses to travel shorter distances, potentially enabling faster reaction times compared to larger dogs. Smaller dogs also have faster metabolisms that contribute to higher levels of energy. Finally, smaller dogs have smaller bladders, which can mean more accidents while house training.

But, this study questioned if these findings were based solely on the physical characteristics of the dog themselves or if there were other factors that contributed to these findings.

Research has found that owners of small dogs often train their pets less consistently. The study posited that people may be more tolerant of undesirable behavior among small dogs and may therefore be more relaxed or inconsistent when managing these behaviors. After all, in many ways, it is easier to clean up after small dogs when they have an accident in the home.

Also, owners of larger dogs have more of a fear of something going wrong, such as their dog attacking another dog or a human. But, with dogs of any size, less consistency and less follow through leads to poorer training outcomes.

The study also questioned whether people tend to over-indulge or over-protect smaller dogs, might this contribute to higher rates of behavioral problems in small dogs. Large dogs often have more structured routines because their size demands it. Research has found that owners of large dogs are more likely to start training dogs earlier, set boundaries, and use leashes on regularly scheduled walks.

If you can’t resist the adorable face of a smaller breed or your home simply can’t accommodate a larger breed, remember these tips to help counterbalance the biological factors that cause smaller dogs to be less trainable:

• Start training your dog at a young age, focusing on positive reinforcement of good behavior. Think yummy dog treats and belly rubs.
• Be consistent with the training process. Continue to reinforce positive behaviors and redirect for behaviors that you want to decrease.
• Set up structured routines. The more predictable the dog’s routine is, the lower their arousal will be which can lead to fewer reactive, in-the-moment behavioral abnormalities.
• Avoid stepping in too quickly or too often in an attempt to shield your dog from challenge or frustration. There is no need to console your dog at the first sign of fear or barking.
• Allow dogs to play with other dogs safely and independently.

Remember, all dogs are trainable with the right owner attitude. Smaller dogs may simply require a different approach to training since they are naturally inclined to be more fearful and more excitable.