Animus (law)

In criminal law, animus nocendi ("intention to harm"^[1]) refers to an accused's guilty state of mind with respect to the actus reus of the crime. It is thus analogous to mens rea, a more commonly used term in common law countries. The term dates back to Roman understandings of censorship, where it referred to an author's impermissible intention in writing a literary work.^[2]

In Scots law, the term animus malus ("evil intention"^[1]) is sometimes used.^[3]

In family law, animus deserendi refers to one spouse's firm intention to leave the matrimonial home—and hence the marriage.^[4] When combined with the "factum of separation," it "constitute[s]" desertion.^[5] Proof of desertion, in turn, has been grounds for divorce in some legal systems.^[6][7]

In property law, animus possidendi ("intent to possess") refers to a person's manifest intention to control an object, and is one of the two elements—along with factum possidendi (the "fact of possession")—required to establish property in an object by first possession.^[8]

In both civil and common law, animus revertendi ("intent to return") distinguishes an animal in which a person may have a property right from a wild animal (which one cannot own) by reference to the animal's habitual return to a person who cares for it.^[9] For example, if a housecat regularly goes outdoors, but returns home each day, the cat's owner does not stop owning the cat during the time the cat is in a neighbor's garden. Blackstone describes the doctrine as follows:

The law therefore extends … possession farther than the mere manual occupation; for my tame hawk that is pursuing his quarry in my presence, though he is at liberty to go where he pleases, is nevertheless my property; for he hath animum revertendi. So are my pigeons, that are flying at a distance from their home … and likewise the deer that is chafed out of my park or forest, and is instantly pursued by the keeper or forester: all which remain still in my possession, and I still preserve my qualified property in them. But if they stray without my knowledge, and do not return in the usual manne[r], it is then lawful for any stranger to take them.^[10]