A Rescue Centre's Plan to Mix Two Macaque Species
A rescue centre near Thrissur holds eight bonnet macaques (one adult male, four adult females, two juveniles and one infant) and three lion-tailed macaques (one adult male and two adult females). The centre has lost a grant and proposes to combine all eleven animals in one 6 m × 4 m outdoor cage with a single feeding platform to save staff time. The cage has a concrete floor, a rope swing and no visual barrier. The lion-tailed macaques are arboreal and the bonnets are already habituated to visitors. A volunteer reports that the bonnets crowd the door at feeding time and that one juvenile has a healing bite. The centre director argues that 'all macaques are social' and that mixing will reduce loneliness. A school group is due in three weeks. The student is asked to write a short advisory note before the move.
1. Compare the social organisation and feeding ecology of bonnet and lion-tailed macaques and use this to predict three risks of combining them.
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Bonnet macaques are flexible, semi-terrestrial macaques that often live in multi-male, multi-female groups and tolerate close human presence; lion-tailed macaques are rainforest specialists, largely arboreal and frugivorous, and are far less tolerant of crowding and disturbance. Three risks follow. First, cross-species aggression: the bonnets, especially the adult male, may dominate the single feeding platform and injure the smaller lion-tailed group. Second, dietary mismatch: lion-tailed macaques need fruit and browse, not the bonnets' provisioned diet, and a single platform prevents species-specific feeding. Third, stress and disease: a concrete 6 m × 4 m cage with no visual barrier gives no escape, and the healing bite shows aggression is already present. Visitor traffic in three weeks adds another stressor. The statement that all macaques are social is true but irrelevant; sociality is species-specific.
2. Design a counter-proposal that uses the same 6 m × 4 m space and no extra money.
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Use the same footprint as two adjoining but visually separated enclosures, not one. Split the 6 m × 4 m with a solid or opaque barrier and a mesh gap, giving each species its own feeding and water points. If the structure cannot be split, rotate access: bonnets out while lion-tailed macaques use the space, and vice versa, with separate holding areas. Add vertical space and browse for the lion-tailed macaques; use puzzle feeders and rope for the bonnets to reduce door-crowding. Move the feeding platform away from the door and scatter feed. Postpone the school visit until behaviour settles. This costs staff time, not new construction, and addresses the director's loneliness argument by improving within-species social housing rather than cross-species mixing.
3. What behavioural indicators would you record to decide whether the move was a failure?
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Record: first, aggression and displacement at feeding, with counts of bites, chases and avoidances; second, feeding and drinking by species, including whether lion-tailed macaques get access; third, stress indicators such as hiding, stereotypy, over-grooming, appetite and faecal consistency; fourth, use of vertical space and retreat; fifth, injuries and veterinary visits. A failure would be rising bite wounds, one species unable to feed, or persistent hiding. Baseline these for one week before any move. Without a baseline, a change cannot be attributed to mixing rather than to the school visit or the new cage.