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Wiki;
Pigs have panoramic vision of approximately 310° and binocular vision of 35° to 50°. It is thought they have no eye accommodation;[36] other animals that have no accommodation, e.g. sheep, lift their heads to see distant objects.[37] The extent to which pigs have colour vision is still a source of some debate, however, the presence of cone cells in the retina with two distinct wavelength sensitivities (blue and green) suggests that at least some colour vision is present.[38] Pigs are inquisitive and this should be remembered when moving them. If they are not hurried and can explore as they go along, they can be driven with much less effort.
Pigs have a well-developed sense of smell and use is made of this in Europe where they are trained to locate underground truffles. Olfactory rather than visual stimuli are used in the identification of conspecifics.[39] Hearing is also well developed and localisation of sounds is made by moving the head. Auditory stimuli are used extensively by pigs as a means of communication in all social activities.[40] Alarm or aversive stimuli are transmitted to conspecifics not only by auditory cues but also by pheromones.[41] Similarly, recognition between the sow and her piglets is by olfactory and vocal cues.[42]
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