Ecology, Conservation and Management of Wild Pigs and Peccaries

Chapter 4: A history of pig domestication

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Five distinct categories of animals have previously been
described for the purpose of domestication studies (Mayer
& Brisbin 1991; Price 2002) that, for pigs, correspond to the
following groups: wild boar – primarily subject to natural selec-
tion; captive wild boar – affected by a relaxation of this natural
selection due to the captive environment; domestic pig –
primarily subject to artificial selection, in addition to the
relaxation of natural selection linked with captivity and man-
agement; cross-breeds of wild and domestic parents; and feral

pigs – corresponding to domesticates that have returned to a

wild state.

Domestication has created completely new dental and cra-

nial morphologies. On average wild boar have larger centroid

sizes of teeth (Cucchi et al. 2011b; Evin et al. 2013, 2015a) and

crania (Owen et al. 2014), although an overlap in size usually

exists in all geometric (GMM) and traditional morphometric

data. In all studies, wild boar and domestic pigs also differ in the

shape of their molars and crania, and in their allometric patterns

Figure 4.1 The outline of the

tooth (A, left) is decomposed into

two periodic functions of X and Y

deviation from the first point

of the outline (A, right). Fourier

decomposition into seven harmonics

enables a good description of the

original form: first harmonics depict

general geometry when latest would

describe more subtle geometry (B).

Figure 4.2 Representation of a

Generalized Procustes Superimposition

using two third lower molars of pig as

an example. This superimposition is

performed by (A) translating,

(B) scaling, and (C) rotating the

objects.

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