What the leash changes
A leash takes away options. Off leash, a dog can choose how to approach, curve around, retreat, sniff, or play. On leash, they are tied to you, and they cannot move the way dogs like to. A head-on approach is rude in dog language, and a tight leash adds pressure on the neck and tension through the body.
Several things stack up:
- Frustration: the dog wants to say hello and cannot. Leash frustration looks like aggression but is a different feeling.
- Fear: the dog cannot flee. When fleeing is not possible, barking and lunging become the tool. Read about fight, flight, freeze and fawn.
- Tension through the leash: dogs read our bodies. Tightening up, shortening the leash and holding breath tells the dog something is wrong.
- Learning: lunging and barking often make the other dog go away. The dog learns it works.
Not every dog who is fine off leash is truly fine. A dog who seems to play may be overexcited, pushy or rude, and some dogs who tolerate dog parks are only coping. Our leash reactivity and distance article explains why this is not about obedience.