Hematology of a natural population of toque macaques (Macaca sinica) at polonnaruwa, Sri Lanka

Abstract

Hematological studies were conducted in three wild groups of toque macaques (Macaca sinica) inhabiting the Polonnaruwa Sanctuary in northeastern Sri Lanka. The macaques were temporarily trapped and anesthetized, and femoral blood was drawn from 35 males and 37 females (age range: 0.33-24.5 yr). Statistically significant (P<0.05) differences were observed by sex for total plasma proteins (PP), and by age for red blood cell (RBC) counts, hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular Hb (MCH), mean corpuscular Hb concentration (MCHC), PP, erythrocyte sedimentation rate (ESR), differential and absolute neutrophil counts, differential lymphocyte counts, and absolute eosinophil counts. In general, the results were similar to those reported for other species of colony-bred and free-ranging macaques. However, there also were differences. First, in contrast to earlier studies of nonhuman primates, we examined the hematology of infants. Compared to other age classes, infants (<1 yr old) had lower RBC, Hb, MCHC, and ESR values, and a higher MCV. These findings were similar to those obtained in human infants. Second, we observed variations in hematology among social groups in relation to their ecology. Two groups (IH3 and M3) had ready access to water throughout the dry season (the period of sampling), whereas the third group (J) did not. The Hb, RBC, and PP values obtained in groups IH3 and M3 were similar to those reported in other macaque species. However, these parameters in group J were significantly (P<0.01) higher, which suggests that this group (representing about 26% of the sample) had been dehydrated during the dry season. Finally, two indices indicative of injury and infection--the ESR and leukocyte counts--were higher in the wild toque macaques than has been reported for other species of macaques held in captivity, and about 15% of the toque macaques sampled had extreme outlier values for these parameters; however, none were visibly ill or died. These results suggest that wild toque macaques are subject to a wide array of physical and biological insults that are unique to natural populations.

Hematology of a Semi-Free-Ranging Colony of Mandrills (Mandrillus sphinx)

“…populations, and comparing hematological parameters between studies difficult. Nevertheless, our reference ranges for mandrills are in general agreement with those for related species (Ekanayake et al, 2003;Harewood et al, 1999). They are also similar to the ones Anderson et al (2004) used in interspecific comparisons, though Semple (2002 reported lower counts for white cells and lymphocytes.…”

“…In toque macaques, Ekanayake et al (2003) also observed that infants had the lowest red cell counts, haemoglobin concentrations and the highest MCV values, but that 3-6.5 yr olds had the highest values for red and white cell counts, haemoglobin, MCH, and MCHC. Again, similar patterns were absent in mandrills.…”

“…They are also similar to the ones Anderson et al (2004) used in interspecific comparisons, though Semple (2002 reported lower counts for white cells and lymphocytes. Lymphocytes (which are involved in adaptive immunity and antigen recognition) and neutrophils (which defend against invading pathogens via nonspecific phagocytosis, Roitt et al, 1998) are equally represented among white cells in the CIRMF mandrills, whereas other studies of nonhuman primates show that neutrophils predominate (Ekanayake et al, 2003;Kessler and Rawlins, 1983;Ramachandra et al, 1998;Riviello and Wirz, 2001;Thierry, 1985). Other white cells were present at low percentages, as in other species.…”

“…White cell counts are slightly higher in female mandrills than in males, which is true also for hamadryas baboons (Harewood et al, 1999), but not for macaques (Ekanayake et al, 2003;Kessler and Rawlins, 1983). In general, male vertebrates exhibit lower immune response and increased vulnerability to parasitic infection than females do (Billingham, 1986;Klein, 2000;Schuurs and Verheul, 1990;Zuk and McKean, 1996), which might result from physiological differences between the sexes, particularly differences in circulating hormone levels (Klein, 2000), as well as differing reproductive strategies (Zuk, 1990).…”

“…Authors of most studies of nonhuman primate hematology use captive individuals, for obvious reasons relating to ease of sampling and their application to medical primatology (cf. Ekanayake et al, 2003;Gotoh, 2000;Kessler and Rawlins, 1983;Takenaka, 1986;Tattersall et al, 1981). Very few researchers have examined intraspecific behavioral or ecological questions, such as the role of immune function in life history trade-offs or sexual selection (Folstad and Karter, 1992;Hamilton and Zuk, 1982;Klein, 2000), though Sapolsky (1993) reported that dominant male baboons have higher levels of circulating lymphoyctes than those of subordinates.…”