Harness or collar, for the dog that pulls

Neither one stops a dog pulling. They decide only where the force lands.

A collar gathers the pressure of a pull into the front of the throat. A harness spreads it across the chest and shoulders. For a dog who lunges at pigeons, that difference is the whole argument.

When a collar is enough

A dog who walks loosely on a slack line is well served by a collar. There is very little force to distribute, and the neck carries nothing that it does not carry already.

When a harness earns its place

Traffic, livestock, other dogs, and any dog who has learned that pulling brings them closer. A harness does not teach a dog to stop pulling. It removes the injury risk while you teach the rest.

The fit that matters

Two fingers under every strap, no strapping behind the front legs, and no gap at the shoulder that a leg can slip through. A harness that shifts sideways under load will rub, however soft the mesh.

The collar still belongs on the dog, carrying the tag. The harness carries the lead. One is identity and one is load, and separating them keeps both honest.