Criminal prosecution of animals

In the Middle Ages animals were tried in local courts for crimes ranging from theft and vandalism, to homicide and sexual perversion: after which they were often executed...

Medieval pigs were widely persecuted by prosecutions due to an unlucky biblical association with demonic possession [Matt. 8:28–34]. They lived close to humans, roaming freely and often sleeping in the same rooms where they would sometimes indelicately snack on small children...

It was illegal to execute without trial... Trials seem to have been entirely sincere, following all the form and ritual of human trials, and trials were expensive...

Animals received the same punishments as people. If convicted of murder, pigs, cows, horses and dogs could be burnt at the stake, hanged, or buried alive. To hang a horse or bull was not a simple matter. Usually the hangman used tree limbs, but occasionally they would build a huge gallows. Sometimes the animals were dressed in human clothes.

Found at Suite 101/Medieval History, via Sloth Unleashed.  There is a book on this subject: The Criminal Prosecution and Capital Punishment of Animals.  Image via Round The Water Trough, where there is additional discussion.