Pennant’s Red Colobus

Taxonomy and Names

Pennant's red colobus belongs to the family Cercopithecidae. It sits within the subfamily Colobinae. George Waterhouse described it in July 1838. He named it Colobus pennantii. The lectotype came from Fernando Poo, the old name for Bioko. Its museum catalog number is BMNH:Mamm:1841.1751.

The name once covered a much wider group. A widely used 2007 treatment recognized four subspecies.^[7] One was the Bioko form itself. The others were Bouvier's, the Niger Delta and Preuss's red colobus. Bouvier's red colobus, P. bouvieri, lives in the Republic of Congo. The Niger Delta form is P. epieni. The fourth is the Critically Endangered Preuss's red colobus. All four are now generally treated as separate species. Today the Bioko monkey stands alone, with no subspecies.

GBIF accepts the name Piliocolobus pennantii.^[8] It lists Procolobus pennantii and Colobus pennantii as synonyms. It is one of many colobus monkeys of Africa in our guide.

The species goes by other names too. In French it is the colobe de Pennant. German speakers call it the Bioko-Stummelaffe. In Spanish it is the colobo rojo de Bioko.

Where It Lives

The species is endemic to Bioko Island. It is the only red colobus in Equatorial Guinea.^[9] The remaining population is believed to occupy about 60 km² of forest. That forest lies in the Gran Caldera de Luba Scientific Reserve. The reserve sits in the island's southwest. It holds both monsoon forest and montane forest. A 2013 estimate put its range at under 500 km².

The monkey once ranged more widely on the island. It may have lived in the Iladyi valley until recently. It persisted in Pico Basilé National Park into the early 1990s. Later studies found no records in either area. Hunters report no sightings on Pico Basilé for over 30 years. A 2022 study considers it locally extinct in that park.^[10]

Within the reserve, densities are low at lower elevations. They are also low in less remote areas. Only this reserve still holds all seven of Bioko's daytime primates.

A 2013 reference work gave its elevation range. It ran from sea level to at least 1,500 m. That is about 4,900 ft. The 2019 IUCN assessment reported observations only below 1,200 m (3,900 ft). Models suggested the species was unlikely above that height. Some southern Bioko forests receive over 10,000 mm of rain a year.

Appearance and Size

The shoulders are dark, speckled red and black. They can look almost solid black. The coat turns bright red on the flanks. The underparts range from pale reddish white to white.

The hands and feet are black. That black runs some way up the limbs. The tail is black above and deep red below. The species resembles Bouvier's red colobus but is darker.

One reference work gives the following measurements. It does not say how many animals were measured. Males measure about 62 cm (24 in) from head to rump. Females measure about 64 cm (25 in). Male tails run about 60 cm (24 in). Female tails reach about 66 cm (26 in). Males weigh about 9 kg (20 lb). Females weigh about 5 to 8 kg (11 to 18 lb).

Diet and Feeding

Its diet has never been measured in the wild. The 2013 reference work lists young and mature leaves. It adds fruit, flowers and buds. Seeds may be eaten as well.

Groups and Behavior

The species is active by day and lives in the trees. Older reports give groups of 5 to 30 animals. Each group had one to three adult males. Females probably leave their birth group. They may travel alone while they do.

Much about its life remains unknown. Its ranging behavior has never been studied in the wild. No breeding information is available.

No nonhuman predation on this species has been documented on Bioko. Crowned eagles, leopards and chimpanzees do not live on the island.

Population and Decline

No full population census exists. The 2021 action plan estimated fewer than 1,200 animals. It also estimated a decline of over 80% from 1986 to 2016.

Earlier figures were less severe. A 2013 reference work gave fewer than 5,000 animals. It cited a 45% decline from 1986 to 2006. More than 550 were estimated killed in 2004 alone.

The warning signs are old. By 1998, the island's red colobus was rapidly becoming very rare.^[11] Across the surveyed monkey community, group encounters had fallen 60% since 1990.

Surveys changed the picture of its range. Researchers once thought it lived throughout Bioko's forests. Surveys elsewhere on the island found no sign of it. The species uses only a small part of the available habitat. That finding supported moving it from Endangered to Critically Endangered.

Main Threats

Hunting is the main threat. Habitat degradation adds to it. Development projects make both problems worse.

A 2016 study found this monkey most vulnerable to gun hunting.^[12] Its relatively large body and group size add to the risk. Its specialized ecology also adds to the risk.^[13] Belebu had 2.89 hunting signs per km. Remote Ureca had just 0.29 signs per km.

Researchers tracked the Malabo bushmeat market for 13 years. From 1997 to 2010, they recorded 196,892 carcasses. Primates made up 35,235 of them. Almost all of those primates had been shot. The market logged 1,754 Pennant's red colobus over that period. Another 679 were recorded up to August 2018.

In October 2007, Decree 72/2007 banned hunting primates. It also banned selling or eating them. Primate carcasses at market fell 87.8% within a month. The ban was not enforced, though. Sales rebounded above pre-ban levels. They peaked at 37.42 primates a day in April 2010. For this species, the market trend did not change significantly.

A paved road from Belebu to Ureca opened in 2015. It cuts straight through the Gran Caldera de Luba reserve. Hunting signs near the road rose after it opened. Mean cartridge encounter rates went from 0.15 to 0.52 per km.

From 2018 to 2020, ten sensors listened for gunshots. They recorded 596 gunshots, some inside the reserve. Hunting rose nearer roads and villages. It fell closer to research camps. The 2021 action plan found rangers there few and unarmed. Hunting had continued unabated since 2010.

Conservation Efforts

In 2017, the Mohamed bin Zayed fund awarded US$11,500 for gunshot detection.^[14] The sensors went into the Gran Caldera de Luba reserve. Partners included Drexel's Bioko Biodiversity Protection Program. The national university of Equatorial Guinea joined too. A training workshop took place in Moka in January 2018.

Re:wild backs ranger and community patrols with a local partner. They focus on the areas with the most red colobus. The North Carolina Zoo supports SMART anti-poaching patrols in the country.

The 2021 action plan set clear priorities. It called for a management plan for the reserve. It urged a ban on all shotgun hunting. It asked for patrols and bushmeat checkpoints. An island-wide survey would target southern Pico Basilé and the Iladyi valley. The plan estimated a budget of US$160,000. That excludes long-term and recurring costs.

Want to meet more primates like this one? Browse our full guide to the many types of monkeys.

Pennant's Red Colobus FAQ