Social enhancement for caged macaques: 15-26

Adult/infant pairs (photos15-26)

Photo 15*: Housing rhesus in pairs is a relatively safe alternative to group-housing.

"To enhance the life-style of a primate, one of the most effective, but often over-looked improvements is pair housing" [Rosenberg & Kesel, 1994].

"Little risk and no extra financial burdens are involved in enriching the barren environment of singly caged rhesus monkeys by carefully socializing them with each other or with surplus infants from breeding troops" [Reinhardt, 1987].


Photo 16: Adults - both females and males - are normally inhibited to show overt aggression against young animals who are not older than 18 months. This makes it possibly to introduce naturally weaned, surplus infants to individually caged adults without undue risk [Reinhardt et al., 1987b; cf. Redican & Mitchell, 1973].
Here, 12-year old George protectively holding his 13-month old companion Billy shortly after pair formation [Reinhardt, 1991b].

In a study with 13 adult male/infant pairs, partners were compatible in 92% of cases throughout a one-year follow-up period [Reinhardt, 1994a].

Partners devote much of their time grooming each other and playing with each other [Reinhardt & Dodsworth, 1989].




Photos 17 & 18: Adult rhesus males have a particularly bad reputation for being unpredictably vicious [Wickings & Nieschlag, 1980]. The idea of pairing them with infants originated from the observation that males of breeding troops never injure infants but rather don't hesitate to cradle them (photo 17: 13-year old male with infant) and carry them around (photo 18: 5-year old male with infant) in a remarkably gentle manner [cf. Capitanio & Taub, 1992].



Photo 19: Gina, an adult female rhesus huddling with her companion Gregg shortly after pair formation [Reinhardt, 1987].

In a study with 65 adult female/infant pairs, partners were compatible in 94% of cases throughout a one-year follow-up period [Reinhardt, 1994a].



Photos 20 & 21*: Pair-housing and active research
(photo 20: remote infusion-and-blood-collection-study requiring the tethering of the adult partner;  photo 21: young partner with headcap implant for neureophysiological studies) do not exclude each other [Reinhardt et al., 1989a; Reinhardt, 1991b].



Photo 22*: The presence of the compatible partner in a "companion cage" has a reassuring, protective effect under stress [Bovard, 1959; Mason, 1960; Coe et al., 1982; Gonzalez et al., 1982; Miller et al. 1986; Reinhardt et al., 1989a; Coelho et al., 1991; Cohen et al., 1992; Gust et al., 1994].
This is particularly valuable in the laboratory setting, where the animals are often subjected to disturbing husbandry and frightening experimental procedures – such as chair
 restraint in this photo – which may trigger fear and stress reactions, thereby introducing  uncontrolled variables into research data [Line et al., 1991a; Reinhardt, 1992a; cf. Brockway et al., 1993].

Adult-infant pair compatibility is long-lasting



Photos 23 & 24: Ulla with her infant companion Uta on the day of pair formation (photo 23), and three years later when Uta is five months pregnant (photo 24). Sharing food (photo 24) is a reliable sign of partner compatibility.





Photos 25 & 26: Bruce with his infant companion Bill a few days after pair formation (photo 25), and three years later when Bill is four years old (photo 26).

  Pair formation of adults (photos 27-35)

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