Domesticated animals, explained
Domestic animals such as dogs, cats, and cattle have been genetically adapted over generations to live alongside humans.
Domesticated animals are animals that have been selectively bred and genetically adapted over generations to live alongside humans. They are genetically distinct from their wild ancestors or cousins.
Animal domestication falls into three main groupings: domestication for companionship (dogs and cats), animals farmed for food (sheep, cows, pigs, turkeys, etc.), and working or draft animals (horses, donkeys, camels).
Animals that make good candidates for domestication typically share certain traits:
- They grow and mature quickly, making them efficient to farm.
- They breed easily in captivity and can undergo multiple periods of fertility in a single year.
- They eat plant-based diets, which makes them inexpensive to feed.
- They’re hardy and easily adapt to changing conditions.
- They live in herds or had ancestors that lived in herds, making them easy for humans to control.
The domestication process
Domestication happens through selective breeding. Individuals that exhibit desirable traits are selected to be bred, and these desirable traits are then passed along to future generations.
Wolves were the first animal to be domesticated, sometime between 33,000 and 11,000 years ago. After domesticated dogs came the domestication of livestock animals, which coincided with a widespread shift from foraging to farming among many cultures.
Because most major acts of domestication began before recorded history, we don’t know much about the exact process behind the generations-long journey from wild animal to domesticated pet or livestock. What is clear is that the ancestors of domesticated animals must have already exhibited traits that made them somehow useful to humans—traits that may have ranged from tasty meat to warm coats to a natural affinity for people.
A 2017 study found evidence that early dog-like wolves were indeed genetically disposed to be friendly. That friendliness may have triggered the first mutually beneficial relationships between humans and dogs, in which people gave dogs food or shelter in exchange for the animals’ service as guards or hunting companions. Other genetic evidence has been discovered to support a similar “self-domestication” theory for cats.
From such early human-animal relationships came many generations of breeding in which people bred animals with the most beneficial traits and discarded the undersized, truculent, or otherwise undesirable creatures.
Often, domestic animals, in contrast to their wild counterparts, exhibit a feature known as neoteny—the retention of juvenile traits like soft fur, floppy ears, and bigger heads relative to their body size. One memorable study begun in the Soviet Union in the 1950s found foxes that were bred for domesticable traits began exhibiting neoteny within just a few generations. It remains unclear why this happens, though it does often make domesticated animals “cuter” to humans. People also often intentionally select for these juvenile traits in the course of breeding, giving us the pugs, ragdoll cats, and dwarf rabbits of today.
Domestic vs. tame
Domestication is not the same as taming. A domestic animal is genetically determined to be tolerant of humans. An individual wild animal, or wild animal born in captivity, may be tamed—their behavior can be conditioned so they grow accustomed to living alongside humans—but they are not truly domesticated and remain genetically wild.
Captive Asian elephants, for example, are often misinterpreted as domesticated, because they have been kept by humans for thousands of years. However, the majority have historically been captured from the wild and tamed for use by humans. Although then can breed in captivity, like big cats and other wild animals, they are not selectively bred, largely because of their long reproductive cycle. For this reason, there are no domesticated breeds of Asian elephants: They remain wild animals.
Other animals that have modern wild counterparts, such as rabbits, face the opposite challenge: Domestic rabbits are genetically distinct from wild rabbits, but because the populations coexist, lack of understanding about their differences may lead to the assumption that domestic rabbits can survive in the wild. Unlike other feral animals (domestic animals that live in the wild), domestic rabbits lack predator instincts that may aid their survival without human care. Shelters report high numbers of domestic rabbits being abandoned outdoors.