Macaque reproductive patterns range from strictly seasonal breeding to non-seasonal breeding, but factors explaining this variation are not fully understood. Valid reproductive seasonality data are also still lacking for many wild macaque populations because the majority of birth data are from captive animals living outside of their geographic range. We evaluated whether the reproductive seasonality of wild northern pig-tailed macaques falls as expected by the ecological (latitude) or phylogenetic inertia hypotheses in comparison with other macaque species. We recorded monthly occurrences of births (N = 22), copulations (N = 563), and females exhibiting sex skin swellings (N = 18) in one group at Khao Yai National Park (KYNP), Thailand. Births, copulations, and females exhibiting sex skin swellings were significantly different from a random distribution. Using measures of circular statistics and the van Schaik and colleagues’ (Schaik et al. Lee (ed), Comparative primate socioecology, Cambridge University Press, Cambridge, 1999) seasonality categorizations, the population at KYNP is best characterized as moderately seasonal breeding. Despite some inconsistency, macaque reproductive seasonality was significantly influenced by latitudinal location. We broadly found that: (1) non-seasonal breeding macaque populations (birth r-vector < 0.3) lived at latitudes close to the equator between 1°S and 3°N, (2) moderately seasonal breeding macaque populations (0.3 < birth r-vector < 0.7) were found between 3°N and 14°N and at 5°S, and (3) strictly seasonal breeding macaque populations (birth r-vector > 0.7) ranged ≥ 12°N. A strong phylogenetic signal in reproductive seasonality on the macaque phylogeny was also detected. However, further studies of wild macaque populations are still needed to better characterize reproductive seasonality in this taxon.

猕猴繁殖模式的范围从严格的季节性繁殖到非季节性繁殖，但解释这种变化的因素尚不完全清楚。许多野生猕猴种群仍然缺乏有效的繁殖季节性数据，因为大多数出生数据来自生活在其地理范围之外的圈养动物。我们评估了与其他猕猴物种相比，野生北方猪尾猕猴的繁殖季节性是否符合生态（纬度）或系统发育惯性假设的预期。我们记录了每月发生的出生 ( N  = 22)、交配 ( N  = 563) 和表现出性皮肤肿胀的女性 ( N  =  18) 在泰国考艾国家公园 (KYNP) 的一组。出生、交配和表现出性皮肤肿胀的雌性与随机分布显着不同。使用循环统计测量和 van Schaik 及其同事（Schaik 等人 Lee (ed)，比较灵长类动物社会生态学，剑桥大学出版社，剑桥，1999 年）季节性分类，KYNP 的种群被最好地描述为中等季节性繁殖。尽管存在一些不一致，但猕猴的繁殖季节性受到纬度位置的显着影响。我们大致发现：(1) 非季节性繁殖猕猴种群（出生r -vector < 0.3）生活在靠近赤道的纬度，介于 1°S 和 3°N 之间，（2）中等季节性繁殖猕猴种群（0.3 < 出生r-vector < 0.7) 被发现在 3°N 和 14°N 之间以及在 5°S，并且 (3) 严格季节性繁殖的猕猴种群（出生r -vector > 0.7）范围 ≥ 12°N。还检测到猕猴系统发育的生殖季节性强系统发育信号。然而，仍需要对野生猕猴种群进行进一步研究，以更好地表征该类群的繁殖季节性。