Baboon social systems are among the most studied in primates. Solid knowledge of the hamadryas and savannah baboon systems has accumulated, leading to a dichotomic view of baboon social systems. Hamadryas baboons live in multilayered troops based on 1-male units whereas savannah baboons live in multimale multifemale groups based on a network of related females. Less attention has been paid to their West African congenerics, the Guinea baboons, Papio papio. To fill this gap, in 2007 we initiated a long-term study of a baboon troop ranging in the Niokolo Koba National Park in southeastern Senegal. Earlier studies suggested a tendency for a multilayered social system in Guinea baboons, similar to the hamadryas baboon organization. Therefore, as a first approach to analyzing variability in party size and composition, we observed members of the troop crossing an open area from a fixed point for 3 mo during the dry and wet seasons. We counted individuals and recorded changes in composition of both arriving and departing parties. Party size and composition were highly variable on both a daily and a seasonal basis; 45.9% of the arriving parties changed in composition while crossing the open area, either splitting into smaller parties or fusing into larger ones, suggesting a fluid organization. Our data support the existence of neither a hamadryas baboon-like multilayered social organization nor a stable medium-sized multimale multifemale group as in savannah baboons. In light of our data we may need to revise the dichotomic view of baboon social systems and include space for greater variability of their social systems.
The human voice provides a rich source of information about individual attributes such as body size, developmental stability and emotional state. Moreover, there is evidence that female voice characteristics change across the menstrual cycle. A previous study reported that women speak with higher fundamental frequency (F0) in the high-fertility compared to the low-fertility phase. To gain further insights into the mechanisms underlying this variation in perceived attractiveness and the relationship between vocal quality and the timing of ovulation, we combined hormone measurements and acoustic analyses, to characterize voice changes on a day-to-day basis throughout the menstrual cycle. Voice characteristics were measured from free speech as well as sustained vowels. In addition, we asked men to rate vocal attractiveness from selected samples. The free speech samples revealed marginally significant variation in F0 with an increase prior to and a distinct drop during ovulation. Overall variation throughout the cycle, however, precluded unequivocal identification of the period with the highest conception risk. The analysis of vowel samples revealed a significant increase in degree of unvoiceness and noise-to-harmonic ratio during menstruation, possibly related to an increase in tissue water content. Neither estrogen nor progestogen levels predicted the observed changes in acoustic characteristics. The perceptual experiments revealed a preference by males for voice samples recorded during the pre-ovulatory period compared to other periods in the cycle. While overall we confirm earlier findings in that women speak with a higher and more variable fundamental frequency just prior to ovulation, the present study highlights the importance of taking the full range of variation into account before drawing conclusions about the value of these cues for the detection of ovulation.
The Guizhou snub-nosed monkey (Rhinopithecus brelichi) is a primate species endemic to the Wuling Mountains in southern China. With a maximum of 800 wild animals, the species is endangered and one of the rarest Chinese primates. To assess the genetic diversity within R. brelichi and to analyze its genetic population structure, we collected fecal samples from the wild R. brelichi population and sequenced the hypervariable region I of the mitochondrial control region from 141 individuals. We compared our data with those from the two other Chinese snub-nosed species (R. roxellana, R. bieti) and reconstructed their phylogenetic relationships and divergence times. With only five haplotypes and a maximum of 25 polymorphic sites, R. brelichi shows the lowest genetic diversity in terms of haplotype diversity (h), nucleotide diversity (π), and average number of pairwise nucleotide differences (Π). The most recent common ancestor of R. brelichi lived ∼0.36 million years ago (Ma), thus more recently than those of R. roxellana (∼0.91 Ma) and R. bieti (∼1.33 Ma). Phylogenetic analysis and analysis of molecular variance revealed a clear and significant differentiation among the three Chinese snub-nosed monkey species. Population genetic analyses (Tajima's D, Fu's F(s) , and mismatch distribution) suggest a stable population size for R. brelichi. For the other two species, results point in the same direction, but population substructure possibly introduces some ambiguity. Because of the lower genetic variation, the smaller population size and the more restricted distribution, R. brelichi might be more vulnerable to environmental changes or climate oscillations than the other two Chinese snub-nosed monkey species. Am J Phys Anthropol, 2012. © 2011 Wiley Periodicals, Inc.
Kin selection theory predicts that recognition and preferences for kin can be highly beneficial. However, evidence of recognition of offspring by fathers in mammals has accumulated very slowly. Especially, in multi-male groups with a promiscuous mating system, like the chimpanzee, where offspring survival does not seem to depend on paternal care, paternal kin recognition has not yet been observed. In this study, we examined whether adult males of a wild chimpanzee community show recognition of their offspring (as determined genetically) and whether infants prefer to interact with kin rather than with unrelated peers. Our analysis utilises up to 14 years of observational data to investigate if adult males associate more frequently and behave less aggressively with females that carry their offspring. Furthermore, we use grooming and play behaviour to establish whether adult males and youngsters show preferences for kin versus non-kin. We found that, adult males did not associate preferentially with females with which they had offspring, but they were generally less aggressive towards any given female when she had a new born infant. Interestingly, however, fathers maintained these low rates of aggression long after the aggression rates of the non-sires had returned to their basal levels. Furthermore, fathers spent significantly more time playing with their own offspring. Thus, our data show for the first time that wild chimpanzee males can recognise their own offspring. Infants preferred to groom and tended to play more with their maternal siblings, but showed only a weak preference for playing with their paternal siblings when given the choice between similarly aged related and unrelated interaction partners. Despite the fact that paternal care does not play an obvious role in chimpanzee survival, kin recognition is observed in different aspects of the life of adult males and youngsters.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.