Exaggerated Sexual Swellings and the Probability of Conception in Wild Sanje Mangabeys (Cercocebus sanjei)

© 2017, The Author(s). Females of several catarrhine primate species exhibit exaggerated sexual swellings that change in size and coloration during the menstrual cycle and, in some species, gestation. Although their function remains under debate, studies indicate that swellings may contain information males could use to discern ovulation and the probability that a cycle will be conceptive. Here we combine visual ratings of swellings with hormonal data for a group of Sanje mangabeys (18 adult, 3 adolescent females) to determine if their swellings provide reliable information on female fertility. In all cases where ovulation was detected (N=7), it occurred during maximum tumescence, and in 83.3% during the first two days of the “shiny phase,” a period during maximum tumescence when the swelling was brightest. There were no significant differences in maximum tumescence and shiny phase duration among cycles of different probability of conception, although there was a trend toward conceptive cycles exhibiting shorter shiny phases than nonconceptive ones. Only 25% (N=4) of postconceptive swellings developed the shiny phase, and adolescents displayed the longest maximum tumescence and shiny phases. The conspicuous nature of the shiny phase and the frequent overlap between its onset and ovulation suggest that its presence serves as a general signal of ovulation and that the cycle has a high probability of being conceptive. It also suggests that swellings in some Sanje mangabeys are more accurate signals of fertility than in other primates

Averting biodiversity collapse in tropical forest protected areas

The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon¹⁻³. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses⁴⁻⁹. As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world’s major tropical regions. Our analysis reveals great variation in reserve ‘health’: about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.Keywords: Ecology, Environmental scienc

Reproductive characteristics of wild Sanje mangabeys (Cercocebus sanjei)

© 2014 Wiley Periodicals, Inc. An accurate description of reproductive characteristics and ovarian endocrinology is necessary to address questions about the reproductive strategies and life history of a species and for meaningful, cross species analyses. Here we used analysis of fecal estradiol (fE) and behavioral observations to determine for the first time the reproductive characteristics and endocrinology of a wild group (N=18 adult and 3 adolescent females) of Sanje mangabeys (Cercocebus sanjei). The study was conducted in the Udzungwa Mountains National Park, Tanzania, from October 2008 through September 2010. Average cycle length (±SD) was 29.3±3.2 days in adults and 51.4±5.5 days in adolescents. Menses appeared within 5.1±2.1 days in adults and 4.8±0.3 days in adolescents after the end of maximum tumescence, and lasted 6.7±3.1 and 10.3±5.0 days, respectively. Infant death tended to reduce the number of cycles to conception (4.3±1.5 cycles after a surviving infant vs. 2.6±1.0 cycles after infant death). Adolescents cycled for at least 16 months without conceiving. Implantation bleeding began 17.5±0.7 days from the onset of detumescence, and lasted 10.0±1.4 days. Gestation length averaged 171.8±3.4 days. Postpartum amenorrhea lasted 6.7±2.3 months while females whose infants had died resumed cycling within 14.3±5.9 days. The interbirth interval after a surviving infant averaged 20.0±4.3 months. These reproductive characteristics of the Sanje mangabey resembled those of other mangabeys and related cercopithecines, with the exception of an earlier onset and longer duration of menstruation and implantation bleeding. Further information on the physiology of the Sanje mangabey is needed to clarify what factors may cause the unusual characteristics of both, their menses and implantation bleeding. Am. J. Primatol. 76:1163-1174, 2014

Individual Distinctiveness in Call Types of Wild Western Female Gorillas

<div><p>Individually distinct vocalizations play an important role in animal communication, allowing call recipients to respond differentially based on caller identity. However, which of the many calls in a species' repertoire should have more acoustic variability and be more recognizable is less apparent. One proposed hypothesis is that calls used over long distances should be more distinct because visual cues are not available to identify the caller. An alternative hypothesis proposes that close calls should be more recognizable because of their importance in social interactions. To examine which hypothesis garners more support, the acoustic variation and individual distinctiveness of eight call types of six wild western gorilla (<i>Gorilla gorilla</i>) females were investigated. Acoustic recordings of gorilla calls were collected at the Mondika Research Center (Republic of Congo). Acoustic variability was high in all gorilla calls. Similar high inter-individual variation and potential for identity coding (PIC) was found for all call types. Discriminant function analyses confirmed that all call types were individually distinct (although for call types with lowest sample size - hum, grumble and scream - this result cannot be generalized), suggesting that neither the distance at which communication occurs nor the call social function alone can explain the evolution of identity signaling in western gorilla communication.</p></div

Individual distinctiveness in eight western gorilla call types.

<p>Summary of eight discriminant function analyses, including the identity of the females (F1-6), sample size (n) per female, the % of calls assigned correctly to individual based on discriminant functional analysis (DFA) or cross-validated DFA (C-DFA), relative p-values calculated from pDFAs interactions (P₁ and P₂), number of Functions (F), Wilk's λ, Chi square (χ²) and p-values, number of linear mixed models (M) and significant parameters after LMM and Hochberg correction.</p><p>* In cases with low number of calls a meaningful cross-validation was not possible.</p

Overall Potential for Identity Coding (PIC) for each of eight call types.

<p>The overall PIC (PIC) for each call type is calculated as mean coefficient of inter-individual variation divided by the mean coefficient of intra-individual variation, where each coefficient of variation is averaged over all parameters. Call types include: hoot series (HT), hum (HM), grumble (GR), double grunt (DG), single grunt (SG), copulation grunt (CG), threat grunt (TG), and scream (SC).</p

Acoustic parameters list. Number, type, name and description of parameters used in the analysis.

<p>Acoustic parameters list. Number, type, name and description of parameters used in the analysis.</p

Spectrograms of three call types given by different female gorillas (F1, F2, F4, F6) showing the acoustic variation.

<p>Spectrograms of three call types given by different female gorillas (F1, F2, F4, F6) showing the acoustic variation.</p

Dispersed male networks in western gorillas

AbstractAlthough kin-selection theory has been widely used to explain the tendency of individuals to bias beneficial behaviors towards relatives living within the same social group [1], less attention has focused on kin-biased interactions between groups. For animal societies in which females emigrate, as is the case for mountain gorillas (Gorilla beringei beringei), encounters between males in different groups often involve aggressive displays that can escalate to physical violence and fatal injuries [2, 3]. However, recent findings on the little-studied western gorilla (Gorilla gorilla) indicate that interactions between social groups occur more frequently than they do in mountain gorillas and are often [4, 5], although not always [5, 6], surprisingly nonaggressive. We investigated the pattern of genetic relationships between individuals of different groups and found evidence suggesting a previously unrecognized “dispersed male network” social structure in western gorillas in which the single males leading social groups were usually related to one or more nearby males. We propose that this provides a basis for extra-group, kin-biased behaviors and may explain the reported peaceful intergroup interactions. Furthermore, these results suggest that a patrilocal social structure, in which males remain in their natal region and potentially benefit from kin associations, is a feature unifying African apes and humans