The country’s first rare hybridisation of two samango and vervet monkeys was discovered in the KwaZulu-Natal Midlands, with the research already being peer-reviewed and published.
Internationally renowned baboon-woman Karin Saks found the pair, who have since been named Jackson and Jive, while working on the Samango Monkey Research Project, which aims to better understand samango monkey populations and the status of their habitats.
The findings were scrutinised and subsequently published recently in volume 15 of Primates Africa, a scientific journal.
Saks said her first encounter was in November 2017, when her team headed to the Midlands.
“A sub-adult monkey dashed across the road in a flash of the unfamiliar, strongly contrasting hues of rust, blueish-grey and stark white patches. I’d never seen a monkey that looked like that before. My breath left. I stared in the direction the monkey had disappeared. We slowly inched closer to find a group of vervet monkeys sitting in the branches,” she said.
A key aspect of the project was to observe the relationship between the samango and vervet troops.
Saks said they made an observation that the two species moved together, and sometimes groomed each other, at one of their study sites.
“Given that the two species have a different number of chromosomes with differing diet and habitat requirements, it was unlikely there would be hybridisation. There have only ever been three cases to date. Inter-generic crosses between these two species is exceptionally rare,” she said.
After the team’s first encounter and the troop disappeared, they walked the trails until they found the monkeys, far in the distance.
“Zooming in through our cameras, we were able to identify a juvenile monkey with identical markings as the unusual sub-adult monkey that had just dashed across the road earlier. We named the two remarkable monkeys Jackson and Jive,” she said.
She said the most prominent characteristics distinguishing the hybrids from their parent species were their white hands and feet, full-length white tail with a dark area at the base and the white band around the nose.
“Like samangos, the back legs of the hybrids were longer than the vervet’s. The hybrids’ overall pelage had a grey tone without the yellow hues seen in vervets, but not in samangos. The hair of the hybrids was the same length as that of vervets, while samangos have longer hair. There was a rust tinge along the side of the hybrids’ bodies, which was not obviously present in either parent species,” she said.
The area in the Midlands primarily comprises guest houses, large residential gardens and livestock farms against a backdrop of fragmented mist-belt forest, plantations and grasslands.
Saks said the risks to the monkeys were high, as they were killed by dogs, shot at by residents, trapped for traditional medicine, hit by vehicles, and electrocuted on pylons.
“The hybridisation was likely the result of fragmentation due to the samango’s inability to disperse across the study area. The vervet monkeys have freer reign of the area and the overlap between the two has stemmed alliances, and now the hybridisation.”
Tim Newman, a 30-year veteran primatologist, said hybridisation in primates can occur where the two species meet or overlap.
“Hybridisation isn’t a reproductive or evolutionary strategy. It occurs opportunistically if species are in contact, and also that they recognise each other as potential mates. That latter point is important, and is why most species with overlapping ranges do not hybridise,” he said.
Newman said hybrids between vervets and samangos was rare, because they tended to occupy different habitats.
“Karin’s observations illustrate another factor that can lead to hybridisation, which is human-altered landscapes that impact how species occupy their territories.”