A dog harness is often considered better for dogs than a collar for several reasons, though the choice between the two largely depends on the individual dog's size, behavior, and specific needs. Here are some reasons why a dog harness might be preferable:

1. Reduced Neck Strain: Unlike collars, which are worn around the neck, harnesses distribute pressure across the chest and shoulders. This can be especially important for dogs that tend to pull on the leash, as a collar can strain the neck and potentially lead to discomfort or injury.

2. Better Control: Harnesses provide more control over your dog's movements, particularly if your dog is strong, large, or prone to pulling. Harnesses with front-clip attachments can discourage pulling by redirecting your dog's attention back towards you.

3. Safety: For dogs with delicate throats or breathing issues, such as brachycephalic breeds (short-nosed dogs like Bulldogs and Pugs), a harness is a safer option. Collars can put pressure on their windpipes and exacerbate breathing problems.

4. Escape Prevention: Some dogs are skilled at slipping out of collars, especially if they're anxious or excited. A properly fitted harness reduces the risk of your dog escaping.

5. Training Assistance: If you're working on leash training, a harness can offer more leverage and control during the training process. Some harnesses are designed to discourage pulling behaviors, which can make training more effective.

6. Even Distribution of Pressure: Collars can concentrate pressure on a small area, potentially leading to discomfort or choking. A harness evenly distributes pressure across a larger area, reducing the risk of injury.

7. Health Considerations: Dogs with certain health conditions, such as tracheal collapse or neck injuries, may benefit from using a harness instead of a collar.

8. Reduced Risk of Eye Injury: Some dogs, especially those with protruding eyes (like Pugs and Boston Terriers), are at a higher risk of eye injury when pressure is applied to their necks. A harness eliminates this risk.

9. Puppies and Small Dogs: Puppies and smaller breeds can be more delicate and susceptible to injury from collar-related pressure. A harness can provide a more comfortable and secure option for them.

It's important to note that there are different types of harnesses available, including back-clip, front-clip, and dual-clip options. Each type has its own advantages and disadvantages, so it's a good idea to consider your dog's specific needs and behavior when choosing the right harness.