January 06, 2022

Nocturnal activity of common warthog in Rimoi Game Reserve, central Kenya

Yvonne A. de Jong & Thomas M. Butynski
Eastern Africa Primate Diversity and Conservation Program, wildsolutions.nl

Common warthog Phacochoerus africanus are the smallest of the diurnal bare-skinned large mammals (adult males ≈ 80 kg; adult females ≈ 56 kg). Partly due to their sparse cover of hair and low body fat, they are intolerant of cold and hot air temperatures. They avoid the warmer periods of the day by resting in the shade, mud-wallowing (Figure 1), or retreating to a burrow (Cumming, 2013; Butynski & De Jong, 2018). Although typically diurnal, the odd record exists of common warthog being active at night.

Go to: https://www.wildsolutions.nl/nocturnal_warthog/ to read the full blog

Posted on January 06, 2022 16:00 by dejong dejong | 0 comments | Leave a comment

October 14, 2021

Sympatry between desert warthog Phacochoerus aethiopicus and common warthog Phacochoerus africanus in Kenya, with particular reference to Laikipia County

Thomas M. Butynski & Yvonne A. de Jong, Suiform Soundings 20(1), 33-44.

Abstract: Desert warthog Phacochoerus aethiopicus delamerei and common warthog Phacochoerus africanus are widespread and locally common in the Horn of Africa and Kenya, east of the Eastern Rift Valley. It is of particular interest that these two taxa, the only two extant species in the genus Phacochoerus, occur in sympatry in some regions. Within Kenya, sympatry is known for the northern coast, Tsavo East National Park, Tsavo West National Park, and Meru National Park. This article presents information on a fifth region of sympatry, Laikipia County, central Kenya. Individuals that we judged to be atypical for either desert warthog or common warthog were encountered in Laikipia. New information on the distribution, abundance, population structure, ecology, and behaviour of desert warthog in Laikipia is presented. Laikipia offers considerable opportunity for comparative research on the morphology, molecular biology, ecology, and behaviour of desert warthog and common warthog.

Read the full article at: https://www.researchgate.net/publication/355202593_Sympatry_between_desert_warthog_Phacochoerus_aethiopicus_and_common_warthog_Phacochoerus_africanus_in_Kenya_with_particular_reference_to_Laikipia_County

Posted on October 14, 2021 08:55 by dejong dejong | 0 comments | Leave a comment

September 04, 2021

Is the Southern Patas Monkey Africa’s Next Primate Extinction?

The charismatic, semi-terrestrial, southern patas monkey Erythrocebus baumstarki, is probably now restricted in the protected savannas of the western Serengeti (central northern Tanzania). It seems that, at present, fewer than 200 individuals occupy about 15% (9,700 km²) of their early 20th century geographic range. This large, slender, long-limbed, primate once occurred in the acacia woodlands near Mount Kilimanjaro and in southern Kenya but was extirpated from these areas prior to 2016 due to factors related to the rapidly increasing human population. The main threats are the degradation, loss, and fragmentation of natural habitats, and competition with people and livestock for habitat and water. Poaching and domestic dogs are also threats. As a result, this shy and secretive monkey is listed as ‘Critically Endangered’ on the IUCN Red List of Threatened Species [Website: https://www.iucnredlist.org/species/92252436/92252442].

In the absence of focused conservation actions, it appears that the southern patas monkey will be among the first three primate extinctions recorded for continental Africa during the past century. Miss Waldron’s red colobus Piliocolobus waldroni of southern Ghana and southeastern Côte d’Ivoire was last reliably recorded in 1978, while the Mount Kenya potto Perodicticus ibeanus stockleyi is only known from a museum specimen collected in 1938.

In our recent publication (De Jong, Y.A. & Butynski, T.M. 2021. Is the Southern Patas Monkey Erythrocebus baumstarki Africa’s Next Primate Extinction? Reassessing Taxonomy, Distribution, Abundance, and Conservation. American Journal of Primatology, e23316) we assess the historic geographic distribution of the southern patas monkey and give evidence for its former occurrence in Kenya. We present estimates of the current distribution and population size, review the threats, and express our concern for its continued survival. We conclude with suggestions for conservation actions, including research. The objective of this article is to bring attention to the plight of this poorly known species, thereby promoting its long-term conservation.

Yvonne A. de Jong and Thomas M. Butynski
Eastern Africa Primate Diversity and Conservation Program
Nanyuki, Kenya

Posted on September 04, 2021 05:32 by dejong dejong | 0 comments | Leave a comment

April 25, 2020

The Manyara Monkey: A New Subspecies of Monkey Endemic to Tanzania

Thomas Butynski and Yvonne de Jong
Eastern Africa Primate Diversity and Conservation Program

The taxonomy of the Gentle Monkey Cercopithecus mitis has been debated for many decades, mainly due to the complex and wide distribution of its many subspecies. Tanzania and Kenya, together, support no fewer than eight of the currently recognized 17 subspecies. In the most recent issue of Primate Conservation (Issue 34, April 2020), Butynski and De Jong review the taxonomy and distribution of these eight subspecies and describe a new subspecies endemic to central north Tanzania, the Manyara Monkey Cercopithecus mitis manyaraensis. This new subspecies is named after Lake Manyara which lies near the centre of its geographic range.

Click here to continue reading and for the publication

Posted on April 25, 2020 18:18 by dejong dejong | 0 comments | Leave a comment

June 29, 2019

Seeking images of Cercopithecus mitis opisthostictus

We are searching for good images of Cercopithecus mitis opisthostictus. Although perhaps the most widespread of the C. mitis subspecies, opisthostictus is among the least known and least photographed subspecies.

Here is a brief description of the poorly understood geographic limits of C. m. opisthostictus:

Primarily southeast Congo Basin, DRC, and upper Zambezi Basin, Zambia. North limit near Lukuga R. and west bank Lualaba R. at c. 6ºN, DRC. East limit L. Tanganyika, DRC, and Chambeshi R.and Lunsemfwa R., east Zambia. South limit c. 14ºS, central Zambia. West limit perhaps Kasai R., southwest DRC, and upper Zambezi R., central east Angola and west Zambia. Approximate center of geographic distribution: Lubumbashi, extreme south DRC.

Any good images of opisthostictus would be greatly appreciated.

Thank you!

Kind regards,
Yvonne & Tom

Posted on June 29, 2019 07:34 by dejong dejong | 0 comments | Leave a comment

August 06, 2018

Geographic range, taxonomy, and conservation of the Mount Kilimanjaro guereza colobus monkey (Primates: Cercopithecidae: Colobus)

The Mount Kilimanjaro guereza colobus monkey is endemic to northern Tanzania and southern Kenya, occurring on and near Mount Kilimanjaro/Mount Meru. Currently referred to as “Colobus guereza caudatus Thomas 1885”, this monkey is geographically very isolated, and phenotypically distinct from all other taxa of guereza monkeys. As such, application of the “Phylogenetic Species Concept” resurrects the Mount Kilimanjaro guereza to specific rank as Colobus caudatus. The geographic range of C. caudatus is small (ca. 4030 km2) and in decline, as is the number of individuals and area of habitat. Colobus caudatus qualifies as an IUCN Red List globally “Endangered” species, as a nationally “Endangered” species in Tanzania, and as a nationally “Critically Endangered” species in Kenya. Colobus caudatus is Kenya’s most threatened species of primate. Recommendations for research and conservation actions are provided.

Full publication on: http://www.wildsolutions.nl/colobuscaudatus/ and http://www.italian-journal-of-mammalogy.it/Geographic-range-taxonomy-and-conservation-of-the-Mount-Kilimanjaro-guereza-colobus,82059,0,2.html

Butynski & De Jong (2018) Geographic range, taxonomy, and conservation of the Mount Kilimanjaro guereza colobus monkey (Primates: Cercopithecidae: Colobus). Hystrix.

Posted on August 06, 2018 15:16 by dejong dejong | 4 comments | Leave a comment

July 06, 2018

Pocket Identification Guide of the Primates of East Africa

Yvonne A. de Jong & Thomas M. Butynski
Illustrations & Design Stephen Nash

70 taxa • 32 distribution maps • 73 drawings
More information on: www.wildsolutions.nl/pg

Posted on July 06, 2018 14:56 by dejong dejong | 0 comments | Leave a comment

August 27, 2017

Distribution of Madoqua in East Africa

New publication:

Distributions in Uganda, Kenya, and north Tanzania of members of the Günther’s dik-dik Madoqua (guentheri) and Kirk’s dik-dik M. (kirkii) species groups, regions of sympatry, records of aberrant-coloured individuals, and comment on the validity of Hodson’s dik-dik M. (g.) hodsoni

De Jong, Y.A. & Butynski, T.M. 2017. Gnusletter 34: 11-20

Abstract: This paper summarises what is known about the distributions, in Uganda, Kenya, and north Tanzania, of members of the Günther’s dik-dik Madoqua (guentheri) and Kirk’s dik-dik Madoqua (kirkii) species groups. This includes regions of sympatry that extend from near the Indian Ocean in south Somalia and Kenya westward through central Kenya to central east Uganda. Three traits for distinguishing Günther’s dik-dik M. (g.) guentheri and Smith’s dik-dik M. (g.) smithii from Kirk’s dik-dik M. (k.) kirkii and Cavendish’s dik-dik M. (k.) cavendishi in the field are provided. More than a dozen records (some supported by photographs) of aberrant-coloured (i.e., greyish and all-white) M. (guentheri) are presented. The question of whether Hodson’s dik-dik M. (g.) hodsoni is a valid species/subspecies is reviewed as this taxon appears to be based on several aberrant greyish individuals.

Full article is found on: http://www.wildsolutions.nl/madoqua/

Posted on August 27, 2017 05:08 by dejong dejong | 0 comments | Leave a comment

May 12, 2017

The Mount Kenya Potto is a Subspecies of the Eastern Potto Perodicticus ibeanus

Publication by: Thomas M. Butynski & Yvonne A. de Jong, Eastern Africa Primate Diversity and Conservation Program, Lolldaiga Hills Research Programme, Nanyuki, Kenya
In: Primate Conservation 2017 (31): http://www.primate-sg.org/storage/pdf/PC31_Butynski_De_Jong_Perodicticus.pdf

The Mount Kenya potto is currently considered a subspecies of the western potto (i.e., Perodicticus potto stockleyi). We argue that the Mount Kenya potto is a subspecies of the eastern potto (i.e., Perodicticus ibeanus stockleyi). This subspecies has not been observed alive for 79 years, and is assessed on the 2017 Red List as Critically Endangered (Possibly Extinct). We indicate priority field sites in which to search for P. i. stockleyi.

Posted on May 12, 2017 08:59 by dejong dejong | 3 comments | Leave a comment

October 20, 2016

Photographic Maps for the Primates, Warthogs and Hyraxes of Africa

The design and implementation of effective conservation measures for primates, warthogs and hyraxes requires an efficient, low cost, and accessible resource for the identification of species and subspecies. Although photographs cannot replace an adequate museum collection as a resource for assessing species variation, geotagged photographs are a relatively fast, inexpensive, convenient, and unobtrusive means for detecting and assessing phenotypic variation within a species/subspecies over large areas. The use of photographs to document phenotypic characters will become increasingly important as the collection of specimens for hands-on assessments becomes ever more difficult.

Our 14 newly up-graded on-line photographic maps (or ‘PhotoMaps’; wildsolutions.nl), with over 2400 images (September 2016) of African primates, warthogs and hyraxes, together with the latest distribution maps, provide insight into each taxon’s phenotypic characters, diversity and biogeography. These ‘living’ collections of geotagged images are a practical tool for documenting and discussing diversity, taxonomy, biogeography, distribution and conservation status and, therefore, for planning actions for conservation.

PhotoMaps are useful to those who want to:
• identify species/subspecies;
• know which species/subspecies occur in which areas;
• obtain species/subspecies photographs;
• confirm species distribution;
• describe variation within a species/subspecies, especially as it relates to geographic distribution.

If you have photographs of African primates, warthogs or hyraxes from the less documented areas of Africa (i.e., gaps on the PhotoMaps), please consider contributing them to the PhotoMaps. The photographers name is attached to each photograph. Anyone wishing to use a PhotoMap photograph must obtain both permission and the photograph from the photographer.

Send your photographs, and the coordinates and/or place name of the site where the photographs were obtained, to yvonne@wildsolutions.nl or send me the link to the iNat record.


We thank Arnoud de Jong for his technical expertise and great help with the PhotoMaps.

Posted on October 20, 2016 17:11 by dejong dejong | 2 comments | Leave a comment