Adaptive Value

Criteria for domestication: influences and favorable characteristics

Different researchers have different criteria for domestication, but nearly all agree that there are some criteria that affect the ability of a species to be domesticated. Some animals have barriers to domestication that cannot be overcome. This is easily seen in a comparison of domesticated animals and their closely related non-domesticated cousins.  (List adapted from Fox, 1978).

  • Tameability -  Some argue that tameability also encompasses many of the other criteria and should therefore be given more weight.
  • Adaptability - ability to exist in the environment.
  • Economic viability - includes high fertility, efficient nutrient use, and fast growth. Elephants are an example of a species that have never become truly domesticated because their life span and fertility cycles are so long
  • Able to be bred in captivity - Certain animals (pandas, cheetahs) can be almost impossible to breed outside of the wild and therefore represent a problem in species perpetuation and economic return.
  • Retention of juvenile features - such as floppy ears and barking in dogs and farm-foxes and a lack of wild or aggressive characteristics
  • Not dangerous to humans - Zebras, for example, are particularly nasty to zookeepers and have been killing their handlers over the centuries as first Africans and later European colonialists tried to tame them. 
  • Diet - Animals that are very picky or expensive to feed may die during hard times or be less affordable
  • Mating strategy - domestication requires the controlled breeding of small fractions of the populations. Species that are amenable to directed matings with many animals are easiest to domesticate and breed after domestication
  • Herding or pack instinct - Certain animals do not adhere to a dominance hierarchy and therefore cannot humans as their pack leader or alpha individual.
  • Parental care - species in which the young are given a lot of parental care are easier to domesticate because the young mimic their parents actions and information can be passed between generations genetically and non-genetically.                                                                                                Cartoon by Timothy Harries.         

Adaptive value

In cases of directed selection, many traits that influence selection (see above list) or evolve along with the process of domestication (the traits such as floppy ears and rolled tails seen in the farm-foxes and in modern dogs) may have neutral or even decreased adaptive  value in the wild.  These traits do, however, serve as markers for domestication and may be selected for by humans as proxies of other traits and in this way confer advantage on those animals who have them. In a process of undirected or natural selection, such traits may allow animals to better take advantage of new situations and resource opportunities (the food scraps left by humans) than others without these attributes.