Coprophagy, regurgitation, and reingestion are common in captive apes (Fritz and others 1992b; Howell and others 1997; Morgan and others 1993) and to some degree in wild chimpanzees (Goodall 1968, 1986). It appears that these practices are more frequent when animals are insufficiently occupied, yet providing forage in deep bedding has been implicated as a contributing cause of coprophagy in some animals (Fritz and others 1992). These practices are difficult to eliminate, but the best recommendation possible at present is to provide the animals with a rich social and physical environment and keep indoor areas as free as possible of feces.
Despite the sometimes solitary nature of wild orangutans, all great apes profit from social companionship. Proper social stimulation is crucial for normal development of infant and juvenile animals (Fritz and Howell 1993a; Mason 1965, 1991; Mason and others 1962, 1963), and the adverse consequences of early social restriction are only somewhat ameliorated by later rehabilitation efforts (Davenport and Rogers 1970; Davenport and others 1973; Fritz 1986, 1989; Rogers and Davenport 1970). The advice on early rearing given in Chapter 3 also applies in the case of the apes. Mother-reared female apes generally become competent breeders and mothers and will provide adequate care for their infants in the presence of their usual companions, including their adult male partners. Sometimes the appearance that a mother is not attentive, or is abusive, to her infant stimulates caregivers to intervene. Often, however, these attentions are unneeded or even harmful, and personnel trying to protect infants from the attention of other group members (or from lack of attention from the mother) might do more harm than good by interfering in such situations. One common instance of this is when newborn chimpanzees are not observed to nurse for the first 48 hours or more. If the infant is well hydrated and reasonably active it probably means that it is nursing at night or at other unobserved times, and intervention is not warranted.
Males reared in social groups containing cycling females, infants, and adolescents usually develop normal copulatory skills and paternal behaviors. Socially restricted or nursery-reared males, however, often are inadequate breeders and parents (Fritz 1986). Adult male gorillas display remarkable gentleness in wrestling and play-fighting with older infants and young juveniles.
An issue of concern in today's biomedical chimpanzee colonies is how to sustain male copulatory skills without producing offspring. Owing to the burgeoning biomedical chimpanzee population (NRC 1997b), most chimpanzee-colony managers are attempting different strategies to accomplish this goal, including the use of Norplant® in females, vasectomizing some males that can serve as role models for prepubertal males, and separation of the sexes. It is probably too early to recommend one strategy over the others, for each has merits