Pleasure and Animal Welfare | 415 It allows animals to react adaptively to their environments Being able to detect water movements helps fish orient themselves in murky streams or on migration routes, and to detect the movements of other nearby animals, including potential predators But for group-living species especially, the pleasure of touch acts as a social lubricant, strengthening friendships and defusing tensions For chimpanzees, macaques, and other primates, grooming occupies up to a fifth of their waking time The release of painrelieving endorphins has been shown in grooming primates Few investigators have addressed the pleasure of touch In some cases, animals’ liking of tactile contact may reveal itself by accident For example, in a study in which dolphins could request rewards by pressing plastic symbols on a keyboard with the tips of their beaks, some animals favored getting a rub to getting a fish When human researchers experimentally groomed Camargue horses, the animals’ heart rates slowed significantly more, an indication of pleasurable relaxation, when the touch was directed at areas of the neck that horses prefer when grooming each other Young rats show a mirthful response to the touch of a trusted human Trained to expect a friendly tickle when the human hand is introduced to their space, these rats pursue the hand No food reward is provided; touch is the reward Tickled rats run to the hand about four times as quickly as control rats trained to expect a gentle stroke on the neck Tickled rats also make about seven times more high-pitched chirps during play and other presumably fun activities Brain imaging reveals that a tickled rat shows similar brain activity patterns to those of a human who is enjoying a good laugh The Well-being of a Pleasure-Seeker Animal pleasure has weighty moral implications Being a pleasure-seeker adds considerably more to one’s interests than if one were merely a pain-avoider Being able to feel good means being able to enjoy life There is more at stake, more to be gained, and lost Philosophers for centuries have recognized the significance of pleasure to ethics Utilitarianism, originating in the 18th century, favors actions that optimize pleasurable outcomes while minimizing negative ones Its founder, Jeremy Bentham, regarded animals as serious objects of moral concern, based on their capacity for both pain and pleasure Peter Singer argues that sentient animals have interests, and that those interests involve not just avoiding physical pain and/or psychological suffering but also the experience of pleasure Tom Regan emphasizes the intrinsic value of sentient organisms An individual who can experience good feelings has a life that is of value to that individual, independent of any value it could have to another, such as a source of entertainment or revenue American veterinarian Franklin McMillan adds that such an individual has a quality of life Regarding the human-animal relationship, it is the denial of pleasure, not its bestowal, that has moral weight One has no obligation to provide pleasures to another, be they another animal or a fellow human Bringing flowers to a friend is an act of kindness, but it is not an injustice if I decide to keep them for myself If, however, my friend has flowers and I take them away, then I am violating my friend’s interests, albeit rather trivial ones in this example The pleasures we deny animals are more serious When we keep animals in factory farms, laboratory