I once read about a medieval case where a sow and her piglets attacked and killed a random villager. The medieval court sentenced the mother to death but concluded that the offspring were too young to know right from wrong and were acting under the influence of their mother, ruling them innocent.
There's an old book from about 1906 where the author goes through a bunch of old European cases of animals being tried in court for crimes. It's an interesting and bizarre read.
It also is one of the (potential) bases for laws regarding self-driving vehicles/robots/drones.
Because law builds on precedent. And it can be argued that self-driving vehicles are a bit like an animal (has a "mind" of its own, but has a human owner responsible for it).
