The influence of age, size and sex on feeding in yellow baboons: sexual segregation but not as we know it

Yellow baboons are sexually size dimorphic mammals living in permanent stable mixed-sex troops: Puzzling in the context of our current theory on group living, sexual dimorphism and sexual segregation! This study is the first to investigate how male and female baboons live together despite body size differences. It hypothesizes they use subtle differences in diet and behaviour predicting that Subadult males will be more similar to adult females than larger bodied adult males. Testing this required looking at the behaviour of baboons in new ways by building on long-term research in an area high in abundance and diversity of baboon food species and habitats in Mikumi National Park (Tanzania) Data on dietary profile, space use and activity budgets from three-age-sex classes were collected using focal follows with instantaneous and one-zero recording: 70 individuals in 2 troops, over 270 days across 2 years. Findings demonstrate that baboon diets are diverse not just in terms of species. A range of plant parts and types (including sap and forbs) were eaten plus vertebrates and, especially, invertebrates. Food was packaged in a variety of ways with different processing requirements. Exotic food from a highway was also eaten although only made a very minor contribution to overall diet. Subadult males were more similar to adult females than adult males in their dietary profile (particularly in terms of parts and packages) and activity budgets (particularly in terms of relative allocation of time and number of activities but not synchrony). There were differences between age-sex classes in space use but no consistent patterns emerged. These findings suggest that adult male and female baboons are able to live together and avoid “classic” sexual segregation despite large difference in body size by subtle differences in what they eat but not in where and how they allocate their time for feeding

Hunting or habitat degradation? Decline of primate populations in Udzungwa Mountains, Tanzania:an analysis of threats

Biological ConservationHunting and habitat degradation are universal threats to primates across the tropics, thus deciphering the relative impact of threats on population relative abundance is critical to predicting extinction risk and providing conservation recommendations. We studied diurnal primates over a period of nearly 6 years in the Udzungwa Mountains of Tanzania, a site of global importance for primate conservation. We assessed how population relative abundance of five species (of which two are endemic and IUCNEndangered) differed between two forest blocks that are similar in size and habitat types but contrast strongly in protection level, and how abundance changed during 2004–2009. We also measured habitat and disturbance parameters and, in the unprotected forest, evaluated hunting practices. We found significant differences in primates’ abundance between protected and unprotected forests, with the greater contrast being the lower abundance of colobine monkeys (Udzungwa red colobus and Angolan colobus) in the unprotected forest. At this site moreover, colobines declined to near-extinction over the study period. In contrast, two cercopithecines (Sanje mangabey and Sykes’ monkey) showed slightly higher abundance in the unprotected forest and did not decline significantly. We argue that escalating hunting in the unprotected forest has specifically impacted the canopy-dwelling colobus monkeys, although habitat degradation may also have reduced their abundance. In contrast, cercopithecines did not seem affected by the current hunting, and their greater ecological adaptability may explain the relatively higher abundance in the unprotected forest. We provide recommendations towards the long-term protection of the area

The Prevalence of <i>Leptospira</i> Serovars in African Giant Pouched Rats (<i>Cricetomys</i> spp.) from the Ngorongoro Conservation Area, Tanzania

Leptospirosis, also known as Weil’s disease, is a febrile tropical disease of humans and diverse animals. The maintenance hosts of the infectious pathogen, Leptospira spp., are primarily rodents, while other warm-blooded animals and some reptiles are secondary or transient hosts of this pathogen. African giant pouched rats (Cricetomys spp.) have been identified to be important maintenance hosts of pathogenic leptospires in the tropical and subtropical regions of the world. This study assessed the seroprevalence of Leptospira spp. in the African giant pouched rats of the Ngorongoro Conservation Area (NCA), Tanzania, where there is close human, domestic animal, and wildlife interaction. A total of 50 African giant pouched rats were sampled between July 2020 and December 2021. Blood sera were screened for specific leptospiral antibodies using a microscopic agglutination test (MAT), while urine and kidney tissues were examined for the pathogen and pathogen-specific genes using cultures and polymerase chain reactions (PCR), respectively. The pathogen detection varied from 0% in cultures to 6% via the MAT and 20% via PCR. The Fisher exact test was applied to compare positive cases detected through the diagnostic tests, and showed a significant difference in the indirect and direct detection of Leptospira serovars via the MAT and PCR. We conclude that pathogenic Leptospira serovar are found in the NCA and recommend that the NCA authority raises awareness of the existence of the Leptospira serovar in giant African pouched rats, and possibly other rodents. The NCA should initiate appropriate management strategies, including the guided disposal of household garbage, which is the major attractant of rodents to residential areas. Where necessary, the NCA should carry out limited rodent control and periodic monitoring of the pathogen carrier (rodent) populations

Primates decline rapidly in unprotected forests: evidence from a monitoring program with data constraints

<p>Group count data for the study species: see supplementary model script for further details.</p

Prior (dashed line) and posterior (solid lines) distributions of the parameters for abundance trends, referred to Mwanihana (<i>γ</i>_<i>MW</i>, gray solid line) and Uzungwa Scarp (<i>γ</i>_<i>US</i>, black solid line).

<p>Results are for (A) Angolan colobus, (B) Udzungwa red colobus, and (C) Sykes' monkey. A uniform (-5, 5) prior is used in all cases. The vertical dotted line indicates population stability.</p

Details of line transects, sampling effort, and observers involved in counting primate groups in a protected (Mwanihana, MW) and unprotected forest (Uzungwa Scarp, US) in the Udzungwa Mountains of Tanzania during the dry season of 2002–2012.

<p>Details of line transects, sampling effort, and observers involved in counting primate groups in a protected (Mwanihana, MW) and unprotected forest (Uzungwa Scarp, US) in the Udzungwa Mountains of Tanzania during the dry season of 2002–2012.</p

Results of observed and estimated primate abundance from line transect counts in the Udzungwa Mountains of Tanzania.

<p>Number of primate groups per km of transect at Mwanihana (solid symbols) and Uzungwa Scarp (open symbols) for Angolan colobus (A,B), Udzungwa red colobus (C,D), and Sykes' monkey (E,F). (A), (C), and (E) show the mean observed counts per km (with 1 SE); (B), (D), and (F) show the estimated total number of groups per km (posterior median and 95% CRI). The predicted values for years with no surveys are shown in gray.</p

Posterior summary of model parameters for count data of three primate species (Angolan colobus, Udzungwa red colobus, and Sykes' monkey) for a protected (Mwanihana, MW) and a non protected forest (Uzungwa scarp, US) in Tanzania.

<p>Posterior summary of model parameters for count data of three primate species (Angolan colobus, Udzungwa red colobus, and Sykes' monkey) for a protected (Mwanihana, MW) and a non protected forest (Uzungwa scarp, US) in Tanzania.</p