The Mikeno Gorillas

In the articles we published in 1996 and 1998, we demonstrated the great threat faced by the gorillas in the Congolese part of the Virunga Volcanoes (Mikeno Sector of the Virunga National Park), a threat caused by the state of war and by the demand for baby gorillas. Since then, the situation has deteriorated further as insecurity in the forest continues and the demand for baby gorillas has increased. Since 1995, we have helped to record cases of death among the gorillas due to military operations and to the demand for baby gorillas. In the Congolese part of the Virunga Mountains, the following events were noted:

• 1995: The silverback male Rugabo was killed with two of his females, one baby gorilla was taken away, then confiscated from the poachers and re-introduced to the family.
• In the same year, the silverback male Luwawa was killed for the same motive, i.e. to abduct infants from the group.
• 1996-1997: complete and sudden disappearance of the entire Rafiki family (12 individuals) in the zone of military operations. (In the meantime, the group has been found again in the Mikeno Sector - below the bamboo zone, where no patrols could be made for security reasons.)
• 1997: the silverback male Ndu-ngu-tse was trapped between two lines of fire and killed together with three other gorillas. Several members of this family have not been re-discovered to date. The number of family members fell from 25 to 13 within three months.
• 1998: Two young gorillas of the Lulengo family, one of them a re-introduced baby, were shot and killed quite close to Jomba post.
• 2001: The silverback male Rugendo was also shot and killed between lines of fire of two opposing armies.

Many killings took place in the Democratic Republic of the Congo. On the Rwandan side of the Virungas, we know of one or maybe two gorillas which were killed and partly eaten by Rwandan militia and, in May 2002, two female gorillas of the Suza family were killed and a baby was taken away.
The period prior to 1995 seems to have been much better for the conservation of gorillas. Poachers targeted gorillas only very rarely, or not at all. Although military infiltrations and operations happened frequently in the mountains, the gorillas suffered minimal or no ill consequences.
In December 1994, seven habituated gorilla families, comprising 96 individuals, lived in the Congolese part of the Virunga Massif. By March 1995, their number had increased to 103.
The gorilla families started to be affected in 1995 when the silverback males Rugabo and Luwawa were killed so that baby gorillas could be abducted. The subsequent armed conflicts worsened the situation. By March 1998, the total number of gorillas had decreased to 66 (and during that time very few births were reported compared to the current period).

Group Dynamics
The Lulengo family will soon disperse completely. Things started to go downhill in 1995, when Rugabo was killed, the silverback male who led this family with two of his females. Since then, the number of gorillas in this family has continued to decrease and no births have been observed. The family history is as follows:

• beginning of September 1995: 23 individuals
• end of September 1995: 17 individuals
• June 1996: 13 individuals
• July 1996: 11 individuals
• December 1998: 5 individuals
• December 2001: 3 individuals
• May 2002: 4 individuals. The fourth gorilla was a solitary animal who had joined the family but left it again in June, according to tracks, trampled vegetation etc.

After Rugabo's death, an old female led the family before the blackback male Lulengo took over. In August 1998, an unhabituated silverback male who had been roaming on the fringe of the family's home range attacked Lulengo. The interactions between them lasted for 15 days. The silverback, Mapua, succeeded in splitting off one young female and a juvenile. Later, another female and her baby left Lulengo's group and one subadult male subsequently also joined this family. In September 1998, two juveniles were shot and killed close to Jomba post. The last female left in October, perhaps because she was tired of living on her own with only males for company. By now, the number of gorillas had decreased to 5, all of which were males. In the meantime, Lulengo had grown up to a silverback.
Until February 2002, the composition of this family remained the same. In February 2002, two males left the family and became solitary. They were Pilipili, who had also become a silverback by then, and the blackback Karema. This left the family with three individuals: one silverback and two blackback males. We think that, as these two blackback males are also destined to become solitary males, this family has become dysfunctional. The silverback Lulengo has accomplished his task, which was to ensure that the young would grow up.
The Munyaga family seems to exhibit the same trend as the Lulengo family. This family was formed in the beginning of 1997, and Munyaga acquired females when the former group leader Buhanga was very weak after a savage fight with the silverback male Kabirizi on 6 February 1998. The group had many interactions with Kabirizi during March and April 1998, in February 1999 and in December 1999, and lost a total of six individuals. Currently (May 2002), the family includes one silverback male, two blackback males, two subadults, whose gender has not yet been determined, and one juvenile. Again, the absence of females and babies is noticeable.
By contrast, the Kwitonda, Mapua and Kabirizi families are entirely stable and their numbers are increasing very quickly. In these families, the number of females is greater than the number of other age/sex classes. The stability of the Kwitonda family dates back to 1994. Mapua's family has been stable since its formation; numbers started to increase with the absorption of females in April and August 1998. This is a young family consisting only of the silverback male, several females and their babies.
The Kabirizi family, which used to be the Ndungutse group until Ndu-ngutse was killed in 1997, contains 31 individuals, the same number that the Ndungutse group contained from 1994 until the beginning of September 1995. Currently, the group includes 13 females and 12 babies.
After having been stable for several years, the Rugendo family is currently decreasing in size. This development was unexpected, as Rugendo, after he had been killed, was succeeded by a habituated silverback from the same family.
Looking at the table above, one cannot but notice that the gorillas went through a comparatively quiet period prior to 1995. From then on, the survival of these apes has been under terrible threat due to the demand for baby gorillas and the pressure exerted by military operations in their habitat. The observed tendencies in the gorilla group structures support the hypothesis that "the number of females determines whether a gorilla group splits up, stays stable or increases in numbers of group members."

	March 98	Dec. 1998	Dec. 1999	Dec. 2000	Dec. 2001	May 2002
Kwitonda	10	12	10	11	12	13
Mapua	-	3	7	7	9	9
Lulengo	11	5	5	5	3	4
Rugendo	18	9	11	11	7	8
Kabirizi	11	14	19	27	27	31
Munyaga	12	12	6	6	6	6
Humba	-	10	9	9	9	11
Solitary males	4	4	4	4	5	4
Total	66	69	71	80	78	86

Déo Kajuga Binyeri, Déo Mbula Hibukabake, Claude Sikubwabo Kiyengo

Déo Kajuga Binyeri has been working for conservation since a long time. He directed several national park stations, for example the station Rumangabo. At the moment he is the Provincial Directeur of the ICCN (Institut Congolais pour la Conservation de la Nature) North Kivu.
Déo Mbula Hibukabake works as Technical and Scientific Director at the provincial ICCN Direction in Goma.
Claude Sikubwabo Kiyengo conducted a gorilla survey in the Maiko National Park from 1989 to 1992, and in 1994 he took part in the gorilla census in Kahuzi-Biega. After that he worked for the ICCN in Goma and from 2000 to 2004 for the IUCN program PPP.After having worked for IUCN to develop programs that will be implemented during the next years, he joined ICCN again in 2006.

Overview Virunga National Park South

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