Searching for Bonobo in Congo

Handsome, seemingly pensive, red colobus on the west bank of the Lomami River, Piliocolobus tholloni.

Red Colobus are among the most beautiful – and difficult — of primates. Their cloaks of red, black and white enchant, but are elusive. Until now, this did not matter in the Lomami National Park. We had only one “sort” of Red Colobus – the beautiful tholloni – on the west bank of the Lomami. We know what it looks like: predictably stunning red cloak, red shoulders even its chest and stomach are tinged red.

Henri, on right in green boots, raiding a hunting camp in the park with ICCN guards, on the same patrol mission where they saw the east-bank red colobus.

But then, in 2016, we received a satellite phone message from Henri Silegowa. Henri is our field leader who several years ago found the dryas monkey in the TL2 landscape. His message was that his team had found a red colobus on the east side of the Lomami River. But red colobus had never been reported there. The endangered parmentieri red colobus was known to be only far to the north of the park.

Piliocolobus parmentieri‘s range was thought to be limited about 60km north of the park until patrol teams started reporting sightings in and near the park in 2016 and 2017.

But everything about this red colobus claimed “parmentieri”. The only photo we had of parmentieri was a hunter killed animal, a picture taken north of the park. Compared to tholloni, it is lighter overall especially its undersides but with a distinctive black cape, black hands and feet.

A hunter-killed parmentieri red colobus from north of the park. The black cape, light undersides and all-black hands are striking.

Henri had seen parmentieri and he sent the photos to prove it:

White shoulders and white upper lip.

Very light throat and chest.

All black hands.

John Oates and Nelson Ting, two Red Colobus enthusiasts, stated in a 2015 article that “Species are the common currency used in ..conservation planning”. Red Colobus, they explained, were dangerously short-changed. Sometimes Red Colobus monkeys are all considered to be one species, sometimes 4, sometimes 9, sometimes as many as 18. And all these different arrangements were proposed within the last 20 years.

According to this interpretation parmentieri is limited to an area north of the Lomami National Park, and within the park there is no red colobus on the east bank of the Lomami River.

The problem is this: If only a single species, then the red colobus species is doing pretty well in terms of conservation. Red Colobus monkeys occur over a wide swath of African forest and in a number of protected areas. BUT if we break Red Colobus into distinct species (as above), then some are in great danger of extinction – indeed some are likely extinct.

Hunter-killed P. tholloni. Shoulders tinged red, face dark.

The problem has been how to break up the species complex: Not only are there confusing variations in coat color between populations, but also changes in cranial structure and vocalization patterns do not all suggest the same species divisions. And there are areas of hybridization. An additional source of information–DNA-based molecular phylogenetics –is now being used. What do the genes say about evolutionary divergence?

All P. parmentieri samples cluster to the exclusion of all other taxa in this phylogenetic tree (see Chaney et al, below)

In the TL2 the phylogenetic tree seems clear. P. tholloni and P. parmentieri are distinct. The Lomami River is known as a barrier for some species such as Lesula. So it is not surprising that the red colobus species on the east is different from that on the west.

Henri setting out with two different surveillance patrol teams from the base Bangaliwa. The teams will be dropped off up-stream in the park.

Why did it take so long to find P. parmentieri? Last year Henri and his teams walked through areas where we had not been since 2012 because of the “terror” spread by Col Thoms.  Col Thoms, greatly weakened, has returned to Balanga West leaving the whole north of the park relatively calm. Last year John organized an elephant census throughout the north of the park and now patrols continue surveillance over areas not monitored between 2012 and 2015.

The increase in patrol coverage everywhere has been important, but particularly in the north of the park.

But Henri’s discovery is not just an extension of parmentieri’s range…it is hope for the species where hope was rapidly fading. P. parmentieri’s range, as previously known, was in the agricultural frontier expanding out from Kisangani. John and Kate Detwiler, in an IUCN red list assessment for the species, report that the Lobaye River forests, once considered parmentieri’s stronghold, are now farmed and the stretches of forest still standing are heavily overhunted. Since Henri’s observations we know the species exists much farther south and in Congo’s newest protected area, the Lomami National Park.

Henri (green boots) on one of the patrol missions that saw P. parmentieri.

Thomas Strushaker, author of The Red Colobus monkeys, says « The sightings are important, … because they mean that parmentieri might have a better chance of surviving. » And he also says, « Red colobus are good indicators of forest health ; they are … extremely prone to hunting pressure. »

May red colobus continue to peer down from the trees along the Lomami River. May that always be so !!

P. tholloni observing from the west bank of the Lomami River.

References:

Chaney, M.E., et al. 2016. Mitochondrial relationships of red colobus monkeys from the TL2 region (Tshuapa, Lomami, Lualaba River Basins), Democratic Republic of Congo, relative to other central African populations. Poster at the International Primate Symposium, Chicago, August 2016

Hart, JA and KM Detwiler in press. Piliocolobus parmentieri. IUCN red list assessment.

Oates,J and N Ting. 2015. Conservation consequences of unstable taxonomies: the case of the red colobus monkeys. Pp 321 – 343 chap15 In A.M. Behie and M.F. Oxenham, Taxonomic Tapestries, the threads of evolutionary behavioural and conservation research. ANU Press, Canberra Australia

Struhsaker TT. 2010. The red colobus monkeys. Oxford : Oxford University Press