Definition
In law, any living creature other than a human being, endowed with the power of voluntary motion. The term is broader than its everyday use suggests: it encompasses not only mammals and common livestock but all non-human animate beings capable of self-movement, including birds, fish, reptiles, and insects, depending on the legal context in which the question arises.
The legal significance of the term turns less on what an animal is than on what kind of animal it is. Historical and modern law alike sort animals into categories that determine ownership rights, liability rules, and regulatory treatment.
---
Common Language
Modern common usage (Wiktionary): Any multicellular organism of the kingdom Animalia — mobile, lacking rigid cell walls, deriving energy from consuming other organisms. Colloquially, often restricted to non-human animals, and still more colloquially to mammals or "beasts."
Historical common usage (Webster's 1913): An organized living being with sensation and voluntary motion, taking food into an internal stomach for digestion; distinguished from plants. Commonly used to mean a lower animal, brute, or beast, as distinct from a human.
The legal gap here is primarily one of precision, not contradiction. Common speech treats "animal" as a broad biological category and sometimes excludes humans by implication. Law formalizes that exclusion explicitly and then further subdivides the category in ways ordinary usage does not. Whether a honeybee, an oyster, or a circus elephant counts as an "animal" for purposes of a specific statute or common-law rule is a legal question the dictionary definition alone cannot answer.
---
Recognized Forms
/SUBTYPES
The classical tripartite division, carried through every major historical law dictionary, remains the backbone of common-law analysis:
DOMITAE NATURAE (tamed/domestic by nature): Animals that have been tamed by man or are by nature gentle and accustomed to human society — horses, cattle, dogs, cats, poultry. At common law, a person may hold absolute property in animals of this class. They are treated as personal property in the fullest sense.
FERAE NATURAE (wild by nature): Animals that retain a wild nature and cannot be fully domesticated — deer, foxes, wild birds, fish in open water. Property rights in ferae naturae are qualified: they belong to the possessor only while in actual possession or confinement. Escape generally ends ownership. This category carries the most significant strict-liability implications in tort.
MANSUETAE NATURAE (gentle or tame by nature): A subset recognized in some authorities, covering animals that are tame by disposition even if not traditionally domesticated — sheep, cows in some framings, certain companion animals. The category overlaps with domitae naturae and is not uniformly distinguished in modern law.
A fourth functional category appears in modern regulatory and tort contexts: ANIMALS WITH KNOWN DANGEROUS PROPENSITIES. This is not a species classification but a legal status: a domestic animal whose owner knows or should know of its dangerous tendencies is treated more like a wild animal for liability purposes. This is the foundation of the "one bite rule" and its modern statutory modifications.
---
Why It Matters in Research
The classification of an animal as wild or domestic is not merely taxonomic — it is often the dispositive legal question. In tort research, the distinction between ferae naturae and domitae naturae determines whether strict liability or negligence governs an injury claim, and which encyclopedia entries apply. Researchers moving between those bodies of law should not assume the same animal is categorized identically across jurisdictions or across time.
Statutory definitions frequently deviate from common law. Animal cruelty statutes, veterinary licensing laws, wildlife regulations, and zoning ordinances each define "animal" independently, sometimes excluding fish, sometimes excluding insects, sometimes including only vertebrates. When researching a statutory context, the common-law classification provides background but should never be assumed to control.
Historical corpus traps: Pre-twentieth-century sources treat property rights in animals as the central legal issue. Tort liability for animal attacks appears, but the regulatory and welfare dimensions of modern animal law are almost entirely absent from the historical dictionaries. A researcher using Bouvier or Black's First Edition to understand modern animal law will find the property framework intact but the welfare, endangered species, and agricultural regulatory frameworks entirely missing.
Anderson's entry is unreliable. The text in the corpus appears corrupted or misdirected — it conflates "animal" with other headwords and introduces irrelevant material. Researchers should not rely on it and should cross-check any proposition attributed to Anderson against another source.
The phrase "animals of a base nature" appears in Black's but not in modern usage. It referred historically to animals in which property rights were recognized but which were considered of low or inferior value — relevant to older pleading contexts but rarely encountered today.
---
Historical Dictionary Support
Black's (both editions) and Bouvier's are closely aligned and mutually reinforcing: both lead with the voluntary-motion definition, both reproduce the domitae/ferae/mansuetae trichotomy, and both link the classification directly to property rights. Rapalje & Lawrence adds the explicit Latin etymology and notes the game laws as a distinct statutory overlay on the common-law framework — a useful reminder that even wild animals could be subject to separate regulatory regimes. Burrill is the most Romanist of the group, grounding the definition in Digest citations and emphasizing the philosophical distinction between animate self-moving things and inanimate movables. This Roman-law foundation explains why the ferae naturae doctrine is so durable: it traces directly to Justinian's Institutes.
What the historical dictionaries collectively miss: the welfare dimension, the modern regulatory state's treatment of animals as subjects of protection rather than purely objects of property, and the emergence of "dangerous animal" as a legal status independent of species. They also predate zoning conflicts over exotic animal ownership, agricultural confinement regulations, and the Endangered Species Act framework — all of which have generated substantial modern law that cannot be mapped onto the classical tripartite scheme without adjustment.
---
Jurisdictional Note
The common-law classification of animals as wild or domestic is broadly consistent across American jurisdictions, but statutory modifications vary substantially. Several states have abolished or modified the common-law "one bite rule" for domestic animals by statute, imposing strict liability for first bites. Wildlife ownership and confinement laws are primarily state law. Researchers should always check whether the relevant jurisdiction has codified or displaced the common-law baseline.
---
Encyclopedia Cross-Reference
Strict Liability and Abnormally Dangerous Activities — Wild Animal Liability (torts_139)
Strict Liability and Abnormally Dangerous Activities — Domestic Animal Liability (Known Dangerous Propensity) (torts_140)
Animal Attack Liability Beyond Strict Liability (Negligence-Based) (torts_211)
The Law Mind Torts & Personal Injury Encyclopedia
---