Publications

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differential habitat utilizati of four cercopithecidae in a kenyan forest.the presence of papio cynocephalus, cercopithecus mitis, cercopithecus aethiops and colobus angolensis in a small coastal forest is attributed to their differential habitat utilization. data on diet, space-use patterns and polyspecific associations are given. habitat partitioning is found to be resource-related and is accomplished through differential reliance on resources as well as different means of exploiting overlapping resources. the implications of the data for understanding the relations ...1977403113
microscopic organization of the ligamenta flava in cercopithecinae.the ligamenta flava have been investigated in cercopithecus pygerythrus (vervet monkey) and c. mitis (blue monkey) at various levels of the vertebral column. it has been shown that in the cervical, thoracic and lumbar regions the topography of these ligaments differs. the cervical ligamenta flava do not extend over the intervertebral joints, while in the thoracic and lumbar regions they reinforce and fuse with the capsule. the ligamenta flava from t4 to s1 replace the interspinous ligaments by e ...1976822678
isolation from african sykes' monkeys (cercopithecus mitis) of a lentivirus related to human and simian immunodeficiency viruses.analysis of serum samples from 100 wild-caught or colony-born sykes' monkeys (cercopithecus mitis) in kenya revealed that 59 animals had antibodies cross-reactive to human immunodeficiency virus type 2 (hiv-2) and to simian immunodeficiency viruses (sivs). a lentivirus, designated sivsyk, was isolated from five of six seropositive asymptomatic sykes' monkeys, but in four cases isolation was possible only after depletion of cd8+ lymphocytes and cocultivation of the cd4(+)-enriched cell population ...19911825855
blue monkeys eat mice. 19883254850
absolute auditory thresholds in three old world monkey species (cercopithecus aethiops, c. neglectus, macaca fuscata) and humans (homo sapiens).we investigated the absolute auditory sensitivities of three monkey species (cercopithecus aethiops, c. neglectus, and macaca fuscata) and humans (homo sapiens). results indicated that species-typical variation exists in these primates. vervets, which have the smallest interaural distance of the species that we tested, exhibited the greatest high-frequency sensitivity. this result is consistent with masterton, heffner, and ravizza's (1969) observations that head size and high-frequency acuity ar ...19883396316
breeding season influxes and the behaviour of adult male samango monkeys (cercopithecus mitis albogularis).troops comprising a high density population of samango monkeys (cercopithecus mitis) in natal province, south africa, experienced an influx of adult males during the breeding season. observation of one troop revealed that these males competed with one another and with two resident males for access to receptive females. although both sexes initiated copulation, attempts to do so were more often successful if female-initiated. males did not interact with non-receptive females and there were no rec ...19873443416
temporal integration in two species of old world monkeys: blue monkeys (cercopithecus mitis) and grey-cheeked mangabeys (cercocebus albigena).changes in auditory sensitivity as a function of signal duration were studied in two species of old world monkeys. testing was conducted under free-field conditions with pure tones 250, 800, 1600, and 4000 hz in frequency. test stimuli ranged in duration from 35-2000 ms. the results showed that the temporal integration functions for the blue monkeys were similar to those reported for rhesus monkeys [t. d. clack, j. acoust. soc. am. 40, 1140-1146 (1966)], but differed significantly from those for ...19863700861
a comparison of vocalizations of red-tailed monkeys and blue monkeys, ceropithecus ascanius and c. mitis, in uganda. 19734206429
territories and movements of sykes monkeys (cercopithecus mitis kolbi neuman) in kenya. 19715004210
the annual reproductive cycle of an african monkey (cercopithecus mitis kolbi neuman). 19715004211
a comparative study of basal metabolism and thermoregulation in a folivorous (colobus guereza) and an omnivorous (cercopithecus mitis) primate species.1. abdominal temperatures (tab) and oxygen consumption (vo2) were measured in two males each of colobus and sykes monkeys. 2. tab in both species had the same range (36 38.5 c), but there were marked differences in the daily rhythms. 3. low ambient temperatures (ta) had little effect on tab; at ta = 33.5 35.5 c. however, tab rose quickly to above 40 c. 4. the thermoneutral zone (tnz) extended from about 5 to 28 c in both species. 5. in the colobus monkeys the basal metabolic rate (bmr) was consi ...19836131775
a spontaneous bronchogenic carcinoma in a sykes monkey (cercopithecus mitis stuhlmani).a male blue monkey (cercopithecus mitis stuhlmani), a subspecies of the sykes group, was purchased from a commercial trapper as an adult in july 1978 and kept at the institute of primate research, kenya, for 2 years. the animal developed acute respiratory distress and died. small nodular foci were found in the lung at necropsy and diagnosed as bronchogenic carcinoma on histopathology.19846502688
positional behavior in five sympatric old world monkeys.observations of positional behavior and habitat use were recorded on focal individuals of five species of old world monkeys at kibale forest, uganda, through the dry season of 1990 and 1991. cercopithecus ascanius, cercopithecus mitis, cercocebus albigena, colobus badius, and colobus guereza commonly utilize five similar types of positional behavior (i.e., quadrupedalism, leaping, climbing, sitting, and standing), but in varying frequencies and situations. as a group, colobines use oblique suppo ...19957645673
gastro-intestinal parasites of the samango monkey, cercopithecus mitis, in natal, south africa.eight gastro-intestinal tracts of cercopithecus mitis labiatus from karkloof, natal, and 121 fecal samples from c. m. erythrarchus from cape vidal, natal, were examined for helminth parasites and/or their eggs. fecal samples from six of the c. m. labiatus were examined for protozoan cysts. five protozoon and six helminth species were identified from c. m labiatus. most adult worms occurred in the caecum and colon, gut regions which also contained the highest volatile fatty acid levels. the eggs ...19947932640
a distinct african lentivirus from sykes' monkeys.asymptomatic infection with simian immunodeficiency virus (siv) has been demonstrated in african sykes' monkeys (cercopithecus mitis albogularis), and virus isolation confirmed infection with a novel siv from sykes' monkeys (sivsyk). macaques inoculated with sivsyk became persistently infected but remained clinically healthy. we utilized polymerase chain reaction amplification to generate a full-length, infectious molecular clone of sivsyk. the genome organization of sivsyk is similar to that of ...19938382307
some gastro-intestinal parasites of zoonotic (public health) importance commonly observed in old world non-human primates in kenya.a study was undertaken to categorise some gastro-intestinal (git) parasites commonly observed in kenyan non-human primates (nhps) on the basis of their health implications for humans. six species of locally available non-human primates, namely olive baboons (papio cyanocephalus anubis), vervet monkey (cercopithecus aethiops), sykes monkey (cercopithecus mitis), black and white colobus (colobus abyssinicus), debrazzas monkey (cercopithecus neglectus) and grey and black mangabeys (cercocebus torqu ...19989776144
phylogenetic analysis of simian t lymphotropic virus type i from kenyan olive baboons (papio anubis), lowland sykes monkeys (cercopithecus mitis), and vervet monkeys (cercopithecus aethiops pygerythrus). 199910357474
vigilance and spatial cohesion among blue monkeys. 199910567837
foraging ecology of the mountain monkey (cercopithecus l'hoesti): implications for its evolutionary history and use of disturbed forest.we present the first systematic field study on the feeding ecology of the mountain monkey (circopithecus l'hoesti), a semi-terrestrial guenon. we compare our results with findings from a concurrent study of blue monkeys (c. mitis doggetti, which have an overlapping home range) conducted over ten months in the nyungwe forest reserve, rwanda. the mountain monkeys spent 35% of observation time feeding on terrestrial herbaceous vegetation. thirty-five fruit and seed species comprised 42% of their di ...200010768348
catarrhine photopigments are optimized for detecting targets against a foliage background.the colour vision of many primates is trichromatic, whereas that of all other mammals is thought to be dichromatic or monochromatic. moreover, the triplets of cone pigments in different catarrhines (old world apes and monkeys) are strikingly similar in their spectral positions. we ask whether the selective advantage of trichromacy lies in an enhanced ability to find edible leaves or fruit. further, we ask whether any factor in these two search tasks has constrained the particular set of cone spe ...200010851115
characterization of a novel simian immunodeficiency virus with a vpu gene from greater spot-nosed monkeys (cercopithecus nictitans) provides new insights into simian/human immunodeficiency virus phylogeny.in the present study, we describe a new simian immunodeficiency virus (siv), designated sivgsn, naturally infecting greater spot-nosed monkeys (cercopithecus nictitans) in cameroon. together with sivsyk, sivgsn represents the second virus isolated from a monkey belonging to the cercopithecus mitis group of the cercopithecus genus. full-length genome sequence analysis of two sivgsn strains, sivgsn-99cm71 and sivgsn-99cm166, revealed that despite the close phylogenetic relationship of their hosts, ...200212134035
life-history parameters of a wild group of west african patas monkeys (erythrocebus patas patas).based on long-term, although intermittent, observations (2 years 4 months of 14 years), we present data on birth seasonality, age at first birth, interbirth intervals, mortality rates, age at first emigration, and population change of a wild population of west african patas monkeys ( etythrocebus patas patas) in northern cameroon. birth season was from the end of december until the middle of february, corresponding to the mid-dry season. in spite of large body size, the patas females had the ear ...200312721784
the skin of primates. 23. a comparative study of the skin of the green monkey (cercopithecus aethiops) and the sykes' monkey (cercopithecus mitis). 196414298299
identification of a new simian immunodeficiency virus lineage with a vpu gene present among different cercopithecus monkeys (c. mona, c. cephus, and c. nictitans) from cameroon.during a large serosurvey of wild-caught primates from cameroon, we found 2 mona monkeys (cercopithecus mona) out of 8 and 47 mustached monkeys (cercopithecus cephus) out of 302 with human immunodeficiency virus (hiv)-simian immunodeficiency virus (siv) cross-reactive antibodies. in this report, we describe the full-length genome sequences of two novel sivs, designated sivmon-99cmcml1 and sivmus-01cm1085, isolated from one mona (cml1) and one mustached (1085) monkey, respectively. interestingly, ...200314610175
the single species hypothesis: truly dead and pushing up bushes, or still twitching and ripe for resuscitation?frank livingstone proclaims himself to be the last living proponent of the single species hypothesis. in sharp contrast, a species-rich, bushy phylogeny is favored by most human paleontologists. is livingstone's proclamation merely contrarian posturing, or does closer inspection warrant reconsideration of just how speciose the hominin lineage is? the high-speciation perspective draws on evidence of speciosity in the cercopithecoidea and punctuated equilibria theory for support. if blue monkeys a ...200314655873
seroprevalence of simian immunodeficiency virus in wild and captive born sykes' monkeys (cercopithecus mitis) in kenya.the sykes' monkey and related forms (cercopithecus mitis) make up an abundant, widespread and morphologically diverse species complex in eastern africa that naturally harbors a distinct simian immunodeficiency virus (sivsyk). we carried out a retrospective serological survey of siv infection from both wild and captive sykes' monkeys from kenya. we compared two commercially available, cross-reactive elisa tests using hiv antigens with a novel sivsyk antigen-specific western blot assay and analyze ...200415511293
gastrointestinal parasites of the guenons of western uganda.from january 1998 to december 2002, we collected 293 fecal samples from free-ranging individuals of the 4 guenon species of western uganda, i.e., redtail guenons (cercopithecus ascanius), blue monkeys (cercopithecus mitis), l'hoesti monkeys (cercopithecus lhoesti), and vervet monkeys (cercopithecus aethiops), to quantify the prevalence of gastrointestinal parasites. helminth eggs, larvae, and protozoan cysts were isolated by sodium nitrate flotation and fecal sedimentation. helminth parasites we ...200415715228
red colobus as prey: the leaping habits of five sympatric old world monkeys.this study explored the leaping habits of five sympatric old world monkeys (colobus badius, colobus guereza, cercopithecus ascanius, cercopithecus mitis and cercocebus albigena) in an attempt to determine why chimpanzees prefer to hunt red colobus. we videotaped the leaps of the monkeys for 3 months in uganda's kibale national park. data were collected on leap preparation time as well as several other variables of the leaps. the leap preparation time of red colobus was found to be about double t ...200515775681
frequent insectivory by two guenons (cercopithecus lhoesti and cercopithecus mitis) in the kalinzu forest, uganda.i investigated the feeding ecology of l'hoest's monkeys (cercopithecus lhoesti) and blue monkeys (cercopithecus mitis) in the kalinzu forest, uganda. although forest guenons are generally thought to be frugivores or folivores, these two guenons spent a large proportion of their time feeding on invertebrates. the l'hoest's monkey and the blue monkey spent as much as 66 and 50% of their time on insectivory, respectively. these proportions of time spent on invertebrate feeding are higher than those ...200616211340
dental microwear variability on buccal tooth enamel surfaces of extant catarrhini and the miocene fossil dryopithecus laietanus (hominoidea).analyses of buccal tooth microwear have been used to trace dietary habits of modern hunter-gatherer populations. in these populations, the average density and length of striations on the buccal surfaces of teeth are significantly cor-related with the abrasive potential of food items consumed. in non-human pri-mates, tooth microwear patterns on both occlusal and buccal wear facets have been thoroughly studied and the results applied to the characterization of dietary habits of fossil species. in ...200516401909
red-tailed monkeys (cercopithecus ascanius) hunt green pigeons (treron calva) in the kalinzu forest in uganda.red-tailed monkeys (cercopithecus ascanius) were observed hunting green pigeons (treron calva) in the kalinzu forest in uganda. during 2 h 39 min, i observed two cases of successful hunting and one case of unsuccessful hunting in a ficus saussureana tree. red-tailed monkeys stalked the pigeons until they were within 2-3 m, and then jumped and caught them. in both successful cases, blue monkeys (c. mitis) ran to the hunting site from adjacent trees in order to poach the prey, and the red-tailed m ...200616467957
spatial distribution of primates in a mosaic of colonizing and old growth forest at ngogo, kibale national park, uganda.primate censuses were conducted in a mosaic of colonizing (two locations) and old-growth forests using line transect methods at the ngogo study site, kibale national park, uganda. black and white colobus monkeys (colobus guereza) were encountered more frequently in the colonizing forests than in the old growth forest, while chimpanzees (pan troglodytes) were encountered more frequently in the old growth forest than in colonizing forests. although not significant, results suggest that blue monkey ...200616479411
primate abundance along five transect lines at ngogo, kibale national park, uganda.using the line transect methods, i studied the primate density at ngogo, kibale national park, uganda for 18 months. comparisons with other studies show that the population of red colobus monkeys (procolobus rufomitratus) and blue monkeys (cercopithecus mitis) is declining, whereas the populations of black-and-white colobus (colobus guereza), red-tailed monkeys (cercopithecus ascanius), grey-cheeked mangabeys (lophocebus albigena), baboons (papio anubis), and chimpanzees (pan troglodytes) remain ...200717330309
enzootic simian piroplasm (entopolypoides macaci ) in wild-caught kenyan non-human primates.three species of non-human primates comprising african green monkeys (agms), (cercopithecus aethiops, n = 89), syke's monkeys (cercopithecus mitis, n = 60) and olive baboons (papio cynocephalus anubis, n = 30), were screened for entopolypoides macaci.200818507704
two incidents of venomous snakebite on juvenile blue and sykes monkeys (cercopithecus mitis stuhlmanni and c. m. albogularis).although rarely observed, predation is thought to be an important factor in the evolution of primate life histories and behavior. here i describe two incidents of snake predation on cercopithecus mitis guenons from kenya. the first case involved a juvenile blue monkey (cercopithecus mitis stuhlmanni) in the kakamega forest, which died following a bite by a gaboon viper (bitis gabonica gabonica). the snake's attempts to ingest its prey were unsuccessful. in the second incident, a juvenile sykes m ...200818704624
prevalence of antibodies and cell mediated immune response against leishmania major in feral nonhuman primates from kenya.in kenya, leishmania major is responsible for human cutaneous leishmaniasis (cl). natural infection with l. major of a vervet monkey and experimental susceptibility of some nonhuman primates (nhps) from kenya has been established. however, there has been no comprehensive study of the prevalence of zoonotic cl in kenya. and also, no investigation has been done to assess whether nhps could be potential reservoir hosts of l. major even when the involvement of reservoir animals is obligatory in tran ...200918983806
primate population dynamics over 32.9 years at ngogo, kibale national park, uganda.we present census data for eight primate species spanning 32.9 years along the same transect at ngogo, kibale national park, uganda, demonstrating major changes in the composition of the primate community. correlated with an estimated decline of ∼89% in the red colobus population was an increase in encounter rates with chimpanzee parties. our data, along with the unusually high rates of predation by chimpanzees on red colobus at ngogo and the fact that the chimpanzee community at ngogo is the la ...201121557287
oesophagostomiasis in non-human primates of gombe national park, tanzania.oesophagostomum sp. is a parasitic nematode that frequently infects wild chimpanzees. although nodular lesions are commonly associated with infection, some wild chimpanzee populations seem to tolerate oesophagostomum nodular lesions while those at gombe and other sites suffer from associated morbidity and mortality. from august 2004 to december 2013, we examined demographic (i.e., age, sex) and individual correlates (i.e., fecal consistency, oesophagostomum egg production) to oesophagostomum-ass ...201627309976
detection of viruses using discarded plants from wild mountain gorillas and golden monkeys.infectious diseases pose one of the most significant threats to the survival of great apes in the wild. the critically endangered mountain gorilla (gorilla beringei beringei) is at high risk for contracting human pathogens because approximately 60% of the population is habituated to humans to support a thriving ecotourism program. disease surveillance for human and non-human primate pathogens is important for population health and management of protected primate species. here, we evaluate discar ...201627331804
female and male life tables for seven wild primate species.we provide male and female census count data, age-specific survivorship, and female age-specific fertility estimates for populations of seven wild primates that have been continuously monitored for at least 29 years: sifaka (propithecus verreauxi) in madagascar; muriqui (brachyteles hypoxanthus) in brazil; capuchin (cebus capucinus) in costa rica; baboon (papio cynocephalus) and blue monkey (cercopithecus mitis) in kenya; chimpanzee (pan troglodytes) in tanzania; and gorilla (gorilla beringei) i ...201626928014
co-infection and cross-species transmission of divergent hepatocystis lineages in a wild african primate community.hemoparasites of the apicomplexan family plasmodiidae include the etiological agents of malaria, as well as a suite of non-human primate parasites from which the human malaria agents evolved. despite the significance of these parasites for global health, little information is available about their ecology in multi-host communities. primates were investigated in kibale national park, uganda, where ecological relationships among host species are well characterized. blood samples were examined for ...201323603520
Evaluating the suitability of planted forests for African forest monkeys: a case study from Kakamega forest, Kenya.As natural forest cover declines, planted forests have come to occupy an increasing percentage of the earth's surface, yet we know little about their suitability as alternative habitat for wildlife. Although some primate species use planted forests, few studies have compared primate populations in natural and nearby planted forests. From March 2006 to July 2010, we conducted line transect surveys and assessed group sizes and compositions in natural and nearby 60-70 year old mixed indigenous plan ...201222076861
social behavior, foraging strategies, and fecal glucocorticoids in female blue monkeys (cercopithecus mitis): potential fitness benefits of high rank in a forest guenon.socioecological theory predicts that aggressive feeding competition is associated with linear dominance hierarchies and reproductive advantages for high-ranking females. female blue monkeys contest fruits and have a linear dominance hierarchy, yet previous research has shown no evidence that high-ranking females benefit from greater feeding success or fertility. here, we assess whether individuals differ in fecal glucocorticoid (fgc) excretion and examine proximate determinants of such differenc ...201121495049
seasonal energetic stress in a tropical forest primate: proximate causes and evolutionary implications.animals facing seasonal variation in food availability experience selective pressures that favor behavioral adjustments such as migration, changes in activity, or shifts in diet. eclectic omnivores such as many primates can process low-quality fallback food when preferred food is unavailable. such dietary flexibility, however, may be insufficient to eliminate constraints on reproduction even for species that live in relatively permissive environments, such as moist tropical forests. focusing on ...201223209651
fecal glucocorticoids as indicators of metabolic stress in female sykes' monkeys (cercopithecus mitis albogularis).because of their mediating role in the stress response and potential effects on fitness, glucocorticoid (gc) hormones are increasingly used to assess the physiological costs of environmental and behavioral variation among wild vertebrates. identifying the proximate causes of gc variation, however, is complicated by simultaneous exposure to multiple potentially stressful stimuli. here, we use data from a partially provisioned social group of sykes' monkeys to evaluate the effects of potential psy ...201020540944
seasonal dietary stress in a forest monkey (cercopithecus mitis).blue monkeys (cercopithecus mitis nyasae schwarz) were studied for a period of 15 months on the zomba plateau in malawi, which experiences pronounced seasonality of climate. 2) as might be expected, the monkey's diet contained most protein per item, and least potential digestion inhibitors, during the warm rainy season of the malawian summer. 3) during the period, however, from october to november, which constitutes the hottest time of the year when the greatest number of trees are flowering and ...198928312188
understanding long-term primate community dynamics: implications of forest change.understanding the causes of population declines often involves comprehending a complex set of interactions linking environmental and biotic changes, which in combination overwhelm a population's ability to persist. to understand these relationships, especially for long-lived large mammals, long-term data are required, but rarely available. here we use 26-36 years of population and habitat data to determine the potential causes of group density changes for five species of primates in kibale natio ...201020349839
sex and age differences in juvenile social priorities in female philopatric, nondespotic blue monkeys.juveniles should choose social partners on the basis of both current and future utility. where one sex is philopatric, one expects members of that sex to develop greater and sex-typical social integration with group-mates over the juvenile period. where a partner's position in a dominance hierarchy is not associated with services it can provide, one would not expect juveniles to choose partners based on rank, nor sex differences in rank-based preferences. we tested these ideas on 39 wild juvenil ...201019953556
enzootic circulation of chikungunya virus in east africa: serological evidence in non-human kenyan primates.chikungunya virus (chikv) is a globally emerging pathogen causing debilitating arthralgia and fever in humans. first identified in tanzania (1953), this mosquito-borne alphavirus received little further attention until a 2004 re-emergence in kenya from an unknown source. this outbreak subsequently spread to the indian ocean, with adaptation for transmission by a new urban vector. under the hypothesis that sylvatic progenitor cycles of chikv exist in kenya (as reported in west africa, between non ...201729016323
recent decline in vegetative regeneration of bamboo (yushania alpina), a key food plant for primates in volcanoes national park, rwanda.the african montane bamboo yushania alpina provides both habitat and food for many species in the albertine rift region. in volcanoes national park (vnp), rwanda, it is especially important as a key food resource for the endangered mountain gorilla gorilla beringei beringei and endangered golden guenon cercopithecus mitis kandti. we examined temporal and spatial variation in bamboo shoots regeneration and consumption by primates, monitored between 2013 and 2018 in 82 16-m2 plots located along tr ...201931506574
frequent water drinking by zanzibar red colobus (procolobus kirkii) in a mangrove forest refuge.isolated populations of procolobus kirkii on uzi island, zanzibar, use rhizophora mucronata-dominated mangrove forest for refuge. three groups, observed over 14 months, spent up to 85% of total observation time in mangroves with brief excursions to adjacent upland coral rag forest, habitat degraded by human cutting. a large proportion of monkeys' diets consisted of plant parts of five mangrove species. water drinking was common and 326 water-drinking events were recorded at a rate of up to 0.87 ...200818651613
male blue monkeys alarm call in response to danger experienced by others.male blue monkeys (cercopithecus mitis stuhlmanni) of budongo forest, uganda, produce two acoustically distinct alarm calls: hacks to crowned eagles (stephanoaetus coronatus) and pyows to leopards (panthera pardus) and a range of other disturbances. in playback experiments, males responded to leopard growls exclusively with a series of pyows and to eagle shrieks predominantly with hacks. responses to playbacks of these alarm call series matched the responses to the corresponding predators, sugge ...200818650188
meat eating by nonhuman primates: a review and synthesis.most nonhuman primates prey on vertebrates. meat-eating, defined as ingestion of vertebrate tissue, occurs in 12 families, ≥39 genera, and ≥89 species. it is most common in capuchins (cebus and sapajus spp.), baboons (papio spp.), bonobos (pan paniscus), and chimpanzees (pan troglodytes) and modestly common in blue monkeys (cercopithecus mitis), callitrichids (callithrix spp. and saguinus spp.), and squirrel monkeys (saimiri spp.). it is uncommon in other cercopithecines, rare in other haplorhin ...202033137551
ant dipping and meat eating by wild chimpanzees in the kalinzu forest, uganda.new evidence of ant dipping and meat eating by chimpanzees was recorded in the kalinzu forest, uganda. we found stems and branches at the nests of driver ants,dorylus molestus, just after chimpanzees had left the spot. fecal samples also revealed that chimpanzees sometimes ate driver ants. the configuration of stems and branches and the condition of holes at the driver ant's nests suggested that chimpanzees used them as wands to dip for ants. the frequency of ant dipping and length of wands may ...200030545196
cheek pouch use, predation risk, and feeding competition in blue monkeys (cercopithecus mitis stuhlmanni).the adaptive function of cheek pouches in the primate subfamily cercopithecinae remains unresolved. by analyzing the circumstances of cheek pouch use, we tested two hypotheses for the evolution of cercopithecine cheek pouches proposed in earlier studies: (1) cheek pouches reduce vulnerability to predation, and (2) cheek pouches increase feeding efficiency by reducing competition. we studied two groups of wild blue monkeys (cercopithecus mitis stuhlmanni) in the kakamega forest, kenya, conducting ...200818613091
testing mechanisms of coexistence among two species of frugivorous primates.1. we examined mechanisms of coexistence between two congeneric species of frugivorous primates, the blue monkey (cercopithecus mitis) and the red-tailed monkey (c. ascanius). 2. we used giving-up densities (the amount of food which animals leave in a patch) in fruit trees to measure foraging efficiency and to evaluate possible mechanisms of coexistence. animals with higher giving-up densities are less likely to persist in the company of those with lower giving-up densities because the former ar ...200617009766
comparative postcranial body shape and locomotion in chlorocebus aethiops and cercopithecus mitis.body weight and length, chest girth, and seven postcranial limb segment lengths are compared between two guenon species, chlorocebus (cercopithecus) aethiops (vervets) and cercopithecus mitis (blue monkeys), exhibiting different habitual locomotor preferences. the subjects, all adults, were wild caught for a non-related research project (turner et al. [1986] genetic and morphological studies on two species of kenyan monkeys, c. aethiops and c. mitis. in: else jg, lee pc, editors. primate evoluti ...200515503342
a simple rule for the costs of vigilance: empirical evidence from a social forager.it is commonly assumed that anti-predator vigilance by foraging animals is costly because it interrupts food searching and handling time, leading to a reduction in feeding rate. when food handling does not require visual attention, however, a forager may handle food while simultaneously searching for the next food item or scanning for predators. we present a simple model of this process, showing that when the length of such compatible handling time hc is long relative to search time s, specifica ...200415002768
social interactions between two sympatric forest guenons, cercopithecus ascanius and cercopithecus mitis, in kenya. 200011093041
variation in seed handling by two species of forest monkeys in rwanda.we examined temporal variability in the handling and dispersal of seeds by two sympatric species of monkeys, the arboreal blue monkey (cercopithecus mitis doggetti) and the more terrestrial mountain monkey (c.l'hoesti). ten months of data on phenological patterns and foraging behavior, including details of seed handling based on scan sampling data, were combined with dung sample data to examine patterns of seed handling. the systematic scan sampling observations showed that blue monkeys and moun ...19989573444
infanticide and infant eating in the blue monkey (cercopithecus mitis stuhlmanni) in the budongo forest reserve, uganda. 19957665124
the perception of vocal signals by blue monkeys and grey-cheeked mangabeys.old world forest primates may need to signal vocally over long distances in noisy habitats. perceptual experiments focused on the audibility of signals in noise were conducted in the laboratory using standard psychoacoustical methods. six human listeners, two blue monkeys (cercopithecus mitis), and two grey-cheeked mangabeys (cercocebus albigena) served as subjects. based upon measurements of east african rain forests (brown and waser 1984) testing was conducted in the presence of simulated rain ...19863732496
leishmania major: the suitability of east african nonhuman primates as animal models for cutaneous leishmaniasis.the susceptibility of four species of east african nonhuman primates to experimental infection with leishmania major was investigated. four syke's monkeys (cercopithecus mitis), two vervet monkeys (cercopithecus aethiops), two baboons (papio cynocephalus), and two brown bushbabies (galago garnettii) were each inoculated intradermally on the left eyelid, left ear, and nose with 0.1 ml of medium containing 1 x 10(7) promastigotes of a characterized l. major strain. all the nonhuman primates except ...19873678449
diet and feeding behaviour of samango monkeys (cercopithecus mitis labiatus) in ngoye forest, south africa.the samango monkey occurs at the southern limit of the range of cercopithecus mitis. greater climatic seasonality at this latitude results in more predictable fruiting patterns. in addition, there are no diurnal sympatric primate frugivores. under these conditions, the diet and feeding strategies of samango monkeys would be expected to differ notably from those of central or east african c. mitis subspecies. contrary to these expectations, the preliminary observations reported here indicate that ...19902323688
frequency and intensity discrimination in mongolian gerbils, african monkeys and humans.frequency (delta f) and intensity (delta i) difference limens were directly compared in mongolian gerbils (meriones unguiculatus), old world african monkeys (cercopithecus mitis, cercocebus albigena), and humans. methods employed a repeating background ax discrimination procedure, and positive (food) reinforcement for animals. for delta i, there were small quantitative differences between the species. at 1 khz, 70 db spl, dls averaged 2.82 db for gerbils, 2.29 db for monkeys, and 0.75 db for hum ...19921618711
seven novel mhc class i alleles identified in cercopithecus mitis.we report here the identification of three cemi-a and four cemi-b novel alleles of cercopithecus mitis.201424673478
identification of a derived dental trait in the papionini relative to other old world monkeys.variation in the shape of teeth provides an immense amount of information about the evolutionary history and adaptive strategy of a mammalian lineage. here, we explore variation in the expression of a purported molar lingual remnant (the interconulus) across the old world monkeys (primates: cercopithecidae) with the aim of elucidating a component of the adaptive radiation of this family. this radiation is characterized by a wide geographic range (asia and africa) as well as diverse dietary niche ...201425100299
maternal kin bias in affiliative behavior among wild adult female blue monkeys.kin-biased cooperative and affiliative behavior is widespread in social mammals and is expected to increase fitness. however, despite evolutionary benefits of cooperating with relatives, demographic circumstances may influence the strength of kin bias. we studied the relationship between maternal kinship and affiliative behavior among 78 wild adult female blue monkeys (cercopithecus mitis) from 8 groups monitored for 1-5 years. we compared behavior and kinship matrices, controlling for rank diff ...201525219933
biogeographic variation in the diet and behaviour of cercopithecus mitis.primate species are characterised by variation in foraging behaviour and dietary composition across their geographic range. here we examine how ecological conditions account for variation in the behavioural ecology of a widespread arboreal guenon, cercopithecus mitis. although substantial variation existed in time budgets, group size, home range and day journey length, clear biogeographic patterns were not apparent. in contrast, dietary variation was correlated with underlying climatic condition ...201425591794
social status and helminth infections in female forest guenons (cercopithecus mitis).when resource competition within primate social groups is effective, high-ranking individuals generally gain fitness benefits. contrary to expectations, female cercopithecus mitis form linear dominance hierarchies without evidence for rank-related variation in fitness-relevant measures, raising questions about the evolution of guenon social structure. here, we test whether social status predicts gastrointestinal helminth infections, known to influence health and morbidity in other mammalian host ...201526060035
agonism and dominance in female blue monkeys.agonistic behavior features prominently in hypotheses that explain how social variation relates to ecological factors and phylogenetic constraints. dominance systems vary along axes of despotism, tolerance, and nepotism, and comparative studies examine cross-species patterns in these classifications. to contribute to such studies, we present a comprehensive picture of agonistic behavior and dominance relationships in wild female blue monkeys (cercopithecus mitis), an arboreal guenon, with data f ...201526378396
the vocal repertoire of adult male blue monkeys (cercopithecus mitis stulmanni): a quantitative analysis of acoustic structure.vocal signals are key elements in understanding species' behavior, sociality, and evolution. quantified repertoires serve as foundations for investigating usage and function of particular signals, and also provide a basis for comparative analyses among individuals, populations, and taxa to explore how entire signal systems evolve. this study presents a descriptive catalogue of all vocal signals used by adult male blue monkeys (cercopithecus mitis stuhlmanni). during 12 months in the kakamega for ...201424130044
diurnal primate densities and biomass in the kakamega forest: an evaluation of census methods and a comparison with other forests.line-transect surveys were conducted at the isecheno study site in the kakamega forest, western kenya to estimate diurnal primate densities. the estimates from several different methods of analysis of census data were compared to "true" density values based on home range size and overlap for two species. the whitesides method [whitesides et al., 1988], which incorporates species-specific mean group spread into its formula for estimating transect width, provided the most accurate density estimate ...200010676710
samango monkeys (cercopithecus albogularis labiatus) manage risk in a highly seasonal, human-modified landscape in amathole mountains, south africa.wild species use habitats that vary in risk across space and time. this risk can derive from natural predators and also from direct and indirect human pressures. a starving forager will often take risks that a less hungry forager would not. at a highly seasonal and human-modified site, we predicted that arboreal samango monkeys (cercopithecus albogularis labiatus) would show highly flexible, responsive, risk-sensitive foraging. we first determined how monkeys use horizontal and vertical space ac ...201728546650
life as a bachelor: quantifying the success of an alternative reproductive tactic in male blue monkeys.in species that live in one-male groups, resident males monopolize access to a group of females and are assumed to have higher reproductive success than bachelors. we tested this assumption using genetic, demographic, and behavioral data from 8 groups of wild blue monkeys observed over 10 years to quantify reproduction by residents and bachelors and compare the success of the two tactics. we used maximum-likelihood methods to assign sires to 104 offspring born in the study groups, 36 of which we ...201526131380
abundance, diversity, and distribution of primates at welel mountain, kellem wollega zone, oromia region, ethiopia.primates are the mammals of the order primate that is characterized by advanced development of binocular vision and enlargement of the cerebral hemispheres. the aim of this study was to investigate the abundance, diversity, and distribution of primates on welel mountain. from august 2017 to february 2018, we collected data from different parts of welel mountain during wet and dry seasons of the year and analyzed them using spss version 20. we identified four primate species: chlorocebus aethiops ...202032454802
widespread treponema pallidum infection in nonhuman primates, tanzania.we investigated treponema pallidum infection in 8 nonhuman primate species (289 animals) in tanzania during 2015-2017. we used a serologic treponemal test to detect antibodies against the bacterium. infection was further confirmed from tissue samples of skin-ulcerated animals by 3 independent pcrs (pola, tp47, and tp_0619). our findings indicate that t. pallidum infection is geographically widespread in tanzania and occurs in several species (olive baboons, yellow baboons, vervet monkeys, and bl ...201829774840
use of male blue monkey "pyow" calls for long-term individual identification.this study examines whether individual adult male blue monkeys (cercopithecus mitis stuhlmanni) can be identified through acoustic analysis of their "pyow" calls. it is possible to reliably assign the pyow call of the blue monkeys of kibale forest, uganda, to the individual caller based on the acoustic properties of the vocalization. analysis of pyows made by a recognizable male over a 10-yr period shows that the acoustic properties of one individual's pyow call can remain relatively constant ov ...199231941215
reproductive biology of sykes and blue monkeys (cercopithecus mitis).thirty-five live births were recorded over a 5-year period from three subspecies of the mitis (sykes and blue) monkey (cercopithecus mitis) maintained outdoors in single-male harem breeding groups. there was no indication of birth seasonality. females of one subspecies, c. m. kolbi, were individually caged, and basic reproductive parameters were monitored. a menstrual cycle length of 31.9 ± 6.0 days was recorded, and there were a large number of irregular cycles. within individuals, mean progest ...198531986789
brief report: normal hematology values of sykes monkeys (cercopithecus mitis albogularis).hematologic values are presented for the sykes monkey (cercopithecus mitis albogularis). the values are, in general, similar to published findings for other primate species. elevated hemoglobin, possibly caused by high altitude, was noted. significant differences of several values between males and females are discussed.198331992010
harem-male replacement and infanticide in the blue monkey (cercopithecus mitus stuhlmanni) in the kibale forest, uganda.this paper (1) describes the first observations of male replacement and infanticide in the blue monkey (cercopithecus mitis stuhlmanni), (2) examines these observations in light of those hypotheses put forth to explain infanticide, and (3) presents two basic models through which additional hypotheses are developed. five groups of blue monkeys were observed for 2,724 hr in the kibale forest, uganda. the pattern of infanticide in the blue monkey was strikingly similar to that reported for other sp ...198231992006
high prevalences and a wide genetic diversity of simian retroviruses in non-human primate bushmeat in rural areas of the democratic republic of congo.like the majority of emerging infectious diseases, hiv and htlv are of zoonotic origin. here we assess the risk of cross-species transmissions of their simian counterparts, siv and stlv, from non-human primates (nhp) to humans in the democratic republic of congo (drc). a total of 331 samples, derived from nhp bushmeat, were collected as dried blood spots (dbs, n = 283) or as tissue samples (n = 36) at remote forest sites mainly in northern and eastern drc. siv antibody prevalences in dbs were es ...201728050688
metagenomic analyses reveal previously unrecognized variation in the diets of sympatric old world monkey species.insectivory, or the consumption of insects and other arthropods, is a significant yet cryptic component of omnivorous primate diets. here, we used high-throughput dna sequencing to identify arthropods from fecal dna and assess variation in insectivory by closely-related sympatric primates. we identified arthropod prey taxa and tested the hypothesis that variation in insectivory facilitates niche differentiation and coexistence among closely-related species with high dietary overlap. we collected ...201931242204
mixed-species association of east african guenons: general patterns or specific examples?sympatric guenons in east africa associate with one another in mixed-species groups to an intermediate degree. this makes it possible to compare a given group's ecology and behavior when it is part of an association to when it is unaccompanied, and to correlate association tendency with various ecological parameters. two studies incorporating these approaches have been made of sympatric cercopithecus ascanius and c. mitis monkeys in the kakamega forest, kenya, and the kibale forest, uganda. the ...199031963977
distribution and conservation status of boutourlini's blue monkey (cercopithecus mitis boutourlinii), a vulnerable subspecies endemic to western ethiopia.reliable data on the distribution and threats facing primate species are crucial to identifying priority sites for conservation and designing effective management plans. boutourlini's blue monkey (cercopithecus mitis boutourlinii) is a little-known arboreal primate endemic to the forests of western ethiopia. this subspecies is categorized as vulnerable on the international union for conservation of nature (iucn) red list and the distribution of extant populations is largely unknown. to increase ...202032506350
energy balance but not competitive environment corresponds with allostatic load during development in an old world monkey.primates develop slowly relative to their body size, a pattern posited to result from ecological risk aversion. little is known, however, about how energy balance contributes to allostatic load in juveniles. using data collected over 8 consecutive months, we examined variation in energy balance (as measured by urinary c-peptide) and how energy balance, life history status, and social competition related to allostatic load (as measured by deviation from baseline fecal glucocorticoid metabolites, ...202031899261
early life maternal sociality predicts juvenile sociality in blue monkeys.maternal effects are widespread in living organisms though little is known about whether they shape individual affiliative social behavior in primates. further, it remains a question whether maternal effects on affiliative behavior differ by offspring sex, as they do in other physiological systems, especially in species with high levels of adult sexual dimorphism and divergence in social niches. we explored how direct and indirect experiences of maternal affiliative behavior during infancy predi ...202031373721
dietary generalists and nutritional specialists: feeding strategies of adult female blue monkeys (cercopithecus mitis) in the kakamega forest, kenya.generalist primates eat many food types and shift their diet with changes in food availability. variation in foods eaten may not, however, match variation in nutrient intake. we examined dietary variation in a generalist-feeder, the blue monkey (cercopithecus mitis), to see how dietary food intake related to variation in available food and nutrient intake. we used 371 all-day focal follows from 24 adult females (three groups) in a wild rainforest population to quantify daily diet over 9 months. ...201931273825
energy balance but not competitive environment corresponds with allostatic load during development in an old world monkey.primates develop slowly relative to their body size, a pattern posited to result from ecological risk aversion. little is known, however, about how energy balance contributes to allostatic load in juveniles. using data collected over 8 consecutive months, we examined variation in energy balance (as measured by urinary c-peptide) and how energy balance, life history status, and social competition related to allostatic load (as measured by deviation from baseline fecal glucocorticoid metabolites, ...201930597140
effects of anthropogenic disturbance on primate density at the landscape scale.accurate estimations of the abundance of threatened animal populations are required for assessment of species' status and vulnerability and conservation planning. however, density estimation is usually difficult and resource demanding, so researchers often collect data at local scales. however, anthropogenic pressures most often have landscape-level effects, for example, through habitat loss and fragmentation. we applied hierarchical distance sampling (hds) to transect count data to determine th ...201930561170
spatial patterns of primate electrocutions in diani, kenya.electrocution from power infrastructure threatens many primate species, yet knowledge of effective evidence-based mitigation strategies is limited. mitigation planning requires an understanding of the spatial distribution of electrocutions to prioritize high-risk areas. in diani, a coastal kenyan town, electrocution is an important cause of death for five primate species. in this study we aim to describe the spatial patterns of electrocutions and electric shock incidents (collectively referred t ...201830369684
coloring book: a new method for testing language comprehension.we present a new method for investigating children's language comprehension and argue that it has the potential to mitigate known task-related biases and expose children's grammatical and lexical knowledge in a more natural and ecologically valid manner. the new method consists of filling in a digital coloring page, according to sentence stimuli (e.g., the green monkey is being scratched by the blue monkey; the rabbit is red.). through the playful act of coloring in the page, children reveal the ...201930187431
evidence for paternal kin bias in the social affiliation of adult female blue monkeys.if animals increase inclusive fitness by cooperating with relatives, nepotism should involve maternal and paternal kin equally, all else being equal. evidence of a behavioral bias toward paternal half-siblings in primates is both limited and mixed, with most positive reports from papionins. to expand knowledge of paternal kin recognition, particularly in cercopithecine monkeys, we examined evidence for paternal kin bias in wild blue monkeys (cercopithecus mitis), a species living mostly in one-m ...201829717496
stronger social bonds do not always predict greater longevity in a gregarious primate.in group-living species, individuals often have preferred affiliative social partners, with whom ties or bonds can confer advantages that correspond with greater fitness. for example, in adult female baboons and juvenile horses, individuals with stronger or more social ties experience greater survival. we used detailed behavioral and life history records to explore the relationship between tie quality and survival in a gregarious monkey (cercopithecus mitis stuhlmanni), while controlling for dom ...201829435236
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