02/09/2026
Food for thought: Chihuahua: It Scores High for Aggression in Behaviour Studies, and the Explanation Is Not in the Dog
On canine behaviour scales, the Chihuahua scores above average for aggression, both towards people and towards other dogs. The data is real. The way we usually read it is wrong.
Start with size. An adult Chihuahua stands 15 to 23 centimetres tall and weighs between 1.8 and 3 kilos. It lives in a world where absolutely everything is bigger than it is: a chair, a child, a cat, a stranger who suddenly crouches down to pet it. What would be a neutral situation for a German Shepherd is a constant threat for him.
Then add what we do.
Chihuahuas are rarely socialised. They are not taken to the park to meet other dogs because "he's so small, he could get hurt". They are not trained because "he can't bite hard anyway". They are carried in arms instead of being allowed to walk, which strips them of their natural way of reading a situation and deciding whether to approach or retreat.
And when they growl, we laugh and film it.
That is the exact point. If a thirty-kilo dog growls at a visitor, everyone understands the behaviour needs work. If the one growling weighs two kilos, it becomes a funny video. The behaviour is identical. The difference is that one frightens us and the other strikes us as cute. Nobody teaches a Chihuahua anything, because nobody thinks it is necessary.
Its history says something too. The Chihuahua most likely descends from the techichi, a companion dog of the Toltec civilisation. Figures of similar dogs have been found at the Cholula archaeological site, and the oldest records date to the ninth century. It is one of the oldest breeds on the American continent, and the Fédération Cynologique Internationale made its Spanish name official in 1911.
That dog, with more than a thousand years of history, ended up in the early 2000s as a celebrity accessory, poking out of handbags on red carpets. And when the fashion passed, what always happens happened: the shelters.
This is not a nervous dog. It is a small dog we never let be a dog.