A technique measuring leukocyte (neutrophil) activity was used to examine differences between stress levels in a breeding colony of rhesus macaques housed in either a traditional caging system or open-rooms. The leukocyte activation test measured the degree to which blood from the two treatment groups could launch a further neutrophil response (superoxide production) to an in vitro challenge. Animals housed in a traditional caging system produced a significantly lower leukocyte response than animals housed in open-rooms, indicating that there was a higher level of stress associated with caged housing than open-room housing. This was not influenced by whether animals were physically restrained or trained to stand for a sedating injection. No differences were found between treatment groups in leukocyte numbers or composition. This study validates the use of the leukocyte activation test to assess physiological stress levels in non-human primates and demonstrates the animal welfare benefits of open-room housing over traditional laboratory caging systems.

Captive primates rarely have to spend as much time searching for, obtaining and processing food as do their wild counterparts. Enrichment techniques designed to encourage captive primates to spend more species-appropriate amounts of time in foraging behaviours have been successful. The present study measured the behavioural effects of four feeding enhancements: two devices (mats and puzzles) and two foods (produce and frozen juice), on four cohorts (n = 63) of single-caged, yearling rhesus macaques (Macaca mulatta). Devices required considerable manipulation to retrieve rewards, whereas enrichment foods required additional processing. Analyses compared periods when one of the enhancements was available to interim periods when no enhancements were available. Planned comparisons revealed that subjects spent more time feeding, and less time inactive, self-grooming, exploring and behaving socially when feeding enrichment was available. Significantly more time was spent feeding when enrichment foods were provided, but more time was spent playing and using enrichment when devices were in the cage. More time was spent self-grooming and exploring with the acrylic puzzle than with the artificial turf mat. Subjects spent significantly more time feeding when produce was available than when frozen juice was available. Feeding enhancements resulted in more species-typical patterns of activity for single-caged, yearling rhesus. Since feeding devices were used in species-typical activities in addition to feeding, devices may be more valuable than foods. Feeding enrichment programmes which combine stimulating devices with foods that are novel and require processing can positively affect the behaviour of captive primates.

Large animal species are prone to local extirpation, but ecologists cannot yet predict how the loss of megaherbivores affects ecosystem processes such as seed dispersal. Few studies have compared the quantity and quality of seed dispersal by megaherbivores versus alternative frugivores in the wild, particularly for plant species with fruit easily consumed by many frugivorous species. In a disturbed tropical moist forest in India, we examine whether megaherbivores are a major frugivore of two tree species with easily edible, mammal-dispersed fruit. We quantify the relative fruit removal rates of Artocarpus chaplasha and Careya arborea, by the Asian elephant (Elephas maximus) and alternative dispersers. Through focal watches and camera trapping, we found the elephant to be amongst the top three frugivores for each tree species. Furthermore, seed transects under A. chaplasha show that arboreal frugivores discard seeds only a short distance from the parental tree, underscoring the elephant's role as a long-distance disperser. Our data provide unprecedented support for an old notion: megaherbivores may be key dispersers for a broad set of mammal-dispersed fruiting species, and not just fruit inaccessible to smaller frugivores. As such, the elephant may be particularly important for the functional ecology of the disturbed forests it still inhabits across tropical Asia.

None of the few animal models proposed for the study of human quartan malaria nephritic syndrome have shown complete pathological findings that are similar to those seen in humans. This study investigated the histopathological changes in kidneys in 10 Plasmodium inui infected Macaca mulatta monkeys by light and electron microscopy in order to develop a suitable animal model for human quartan malaria. Ten healthy adult rhesus monkeys were infected with P. inui and clinical chemistry and haematologic tests were done before and after infection. A renal biopsy sample was collected before infection as a baseline control and another biopsy was collected after infection. Histopathological changes examined by light and transmission electron microscopy (TEM) revealed abnormalities in all infected monkeys to variable degrees. Several electron-dense discrete or diffused mesangial deposits, and increase in mesangial cells and matrix were associated with the morphological changes observed by light microscope. This pattern is consistent with membranoproliferative glomerulonephritis type reported in humans infected with Plasmodium malariae. Results strongly support that the P. inui-infected rhesus monkey develop an immune-complex-mediated glomerulonephritis in the course of the infection. Therefore, this experimental model represents a useful tool to better understand the different parameters and the consequences of quartan malaria infections comparable to situations in humans.

This study traces the development of spatial memory abilities in monkeys and reports the effects of selective neonatal hippocampal lesions on performance across development. Two different versions of the visual paired-comparison (VPC) task were used. The VPC-Spatial-Location task tested memory for object-locations that could be solved using an egocentric spatial frame of reference and the VPC-Object-In-Place task taxed memory for spatial relations using an allocentric reference frame. Eleven rhesus macaques (6 neonatal sham-operated controls and 5 with neonatal neurotoxic hippocampal lesions) were tested on both tasks as infants (8 months), juveniles (18 months), and adults (5–6 years). Memory for spatial locations was present by 18 months of age, whereas memory for object-place relations was present only in adulthood. Also, neonatal hippocampal lesions delayed the emergence of memory for spatial locations and abolished memory for object-place associations, particularly in animals that had sustained extensive and bilateral hippocampal lesions. The differential developmental time course of spatial memory functions and of the effects of neonatal hippocampal lesions on these functions are discussed in relation to morphological maturation of the medial temporal lobe structures in monkeys. Implications of the findings for the neural basis of spatial memory development in humans are also considered. (JINS, 2013, 19, 1–12)

The present studies on infections with Leishmania (Viannia) braziliensis in rhesus macaques were made to characterize the evolution of different parasite strains and the immune responses they elicited in this experimental host. A standardized inoculum of promastigotes was injected intradermally either above the eyelid or on the forearm of each monkey. Sixteen infected monkeys developed longstanding infections which lasted until the end of the observation period (33 months). The time required for lesion development was very variable, not only for the isolates showing molecular differences but also for individual animals in groups infected with the same parasite strain. The inocula produced lesions of variable severity, ranging from localized cutaneous leishmaniasis (CL) with a tendency to spontaneous healing to non-healing disease. One infected animal developed persistent metastatic skin and mucosal lesions. Anti-Leishmania antibodies and parasite-specific T-cell responses were induced by the experimental infections. As the granulomatous inflammatory response found at the lesions in L. (V.) braziliensis-infected M. mulatta was similar to that in patients with CL, this primate model could be useful for studying the pathophysiology and immunoregulatory events associated with disease evolution, as well as for the evaluation of new drugs or candidate vaccines.

Rhesus monkeys Macaca mulatta and people have coexisted for many years in Vrindaban in Mathura District, Uttar Pradesh, India. The monkeys are highly valued both by locals and pilgrims to the area, in part because of their quasi sacred status, but during the last two decades the increasing human and monkey populations of the township have led to severe human-monkey conflict and a decrease in people's respect for the monkeys. To ease this situation one of the world's largest ever translocations of monkeys was undertaken. In 1995, 30 groups of rhesus monkeys, comprising an estimated 1,338 individuals, were recorded in Vrindaban. Of these, 12 groups, a total of 600 individuals, were translocated in January 1997 to eight sites in seminatural forested areas within the same District. A post-translocation study indicated that the translocated monkeys were settled and appeared to be exhibiting normal behaviour. This study indicates that translocation of commensal monkeys to forested areas can be a successful technique for their rehabilitation.