Domestication effects on foraging strategies in pigs (Sus scrofa)

It has been suggested that domestic animals have lost the ability to respon d to environmental changes in an adaptive fashion. Others have suggested th at during domestication, a shift may have occurred towards less costly fora ging strategies. Eight domestic pigs (Sus scrofa) and eight crossbred pigs (Holland Landrace x Wild boar) were allowed to forage alone in a maze for 3 0 min on four successive days. The maze contained six gradually depleting f ood patches and corridors between them. Pigs obtained the food by manipulat ing the bucket with the snouts. On every second test the cost of moving bet ween patches was increased by inserting 36.5-38.5 cm high wooden barriers b etween each food patch. Both breeds adapted their foraging pattern to the d epletion of the patches and spent shorter time in each patch on successive visits. Domestic pigs spent longer average time in each patch. Both breeds spent longer time in patches when the maze contained barriers. The ingested amount of feed was reduced in both breeds when barriers were introduced. T he domestic pigs passed totally a lower number of barriers compared with th e crossbred pigs. Both domesticated and crossbred pigs visited fewer patche s in the maze with barriers compared with the maze without. Weight of the p igs was not a major factor affecting the results. We conclude that both cro ssbred pigs and domestic pigs in general responded as expected from optimal foraging theory. Hence, domestic pigs still posses the ability to adapt th eir foraging behaviour in an adaptive fashion to the prevailing conditions. Crossbred pigs seemed to use a more costly foraging strategy than domestic pigs. (C) 1999 Elsevier Science B.V. All rights reserved.