Criteria for domestication: influences and favorable
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).
- Some argue that tameability also encompasses
many of the other criteria and should therefore be given more weight.
- ability to exist in the environment.
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
of juvenile features - such as floppy ears and barking in
farm-foxes and a lack of wild or
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
- Diet -
Animals that are very
picky or expensive to feed may die during hard times or be less
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
or pack instinct - Certain animals do not adhere to a
hierarchy and therefore cannot humans as their pack leader or alpha
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.
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.