The captive diet of any animal should cover, besides the nutrient requirements of the species and the individual, a series of needs that are not directly related to nutrients, but with the food and feeding practice: the non-nutritive requirements. The physical properties of food (texture, consistency, shape, and sensitive properties -smell, taste and color), and the behaviors that the animal carry out to get the food in the wild (for instance bowsing or hunting behaviors), have an important function for the animal. The first are often involved with the diet selection in captivity, and can even be related directly with the health of certain animal structures. For example particle size is related with food selection in many birds, or sweet taste is very palatable for primates. Carnivores fed a soft diet (without bones) develop oral infections. Many times not enough attention is given to feeding behavior. However, it plays an important role on animal welfare. It is described on the literature that there are some behaviors that the animal "needs" to do. For instance, despite of the fact an animal has food available, it may still need to carry out several of the feeding behaviors it would perform in the wild to get that food. Hens need to peck on the floor and pigglets need to root even if they have free access to food. When hens are kept in wire floor cages and pigs are housed on concrete floors without any suitable substrate to root, the energy meant to be used for pecking and rooting respectively is redirected towards other activities, often not desired, like pecking the cage mate or bitting a sibling's ear. In captivity, many behaviors defined as abnormal like stereotypic behaviors, aggression and selfmutilation, among others, may actually be redirected behaviours that indicate the animal's needs are not completely covered. To satisfy the non-nutritive requirements related to feeding, it is essential to know all the natural behavioral paterns that the animals carry out before, during and after food intake. Many of these aspects are contemplated into enrichment programs, but ideally, the diet should also take them into account. Many studies demonstrate the beneficial effects that enrichment programs have on non-desired behaviors, and on enhancing natural ones. Therefore, even if an animal has a well balanced diet according to is nutrient requirements, if it does not cover the non-nutritive requirements as well, the animal may develop behavioral disorders and other diseases.
		A soft diet can lead to terrible consequences on the teeth health of a feline
		Basket with hay to hide part of the diet and stimulate foraging behavior
		Life prey greatly stimulates most of feeding behaviors in faunivores
		Offering arabic gum to the apropriate callitrichid species can stimulate several natural behaviors