Lone Silverback Drama Continues for Inshuti

The lone silverback drama involving Inshuti and his group has continued on through the end of this week, reports the Fossey Fund’s Karisoke Research Center field staff. The dominant silverback truly cannot catch a break from the lone males ranging in the forest tenaciously seeking out females to steal. Yesterday, Karisoke researcher Winnie Eckardt, PhD. and research assistant Samedi Muyco witnessed an interaction that lasted from early morning to late afternoon and had the females of the group shaking with fear. This particular interaction involved Giraneza, an impressive lone silverback who split from Pablo’s group four years ago when he was just 13 years old.

But Giraneza wasn’t the only lone silverback threatening Inshuti’s group on Thursday. Also on the trail was Tuyizere, the lone male who has been making frequent appearances in the Karisoke-monitored groups throughout the last several months. When the field team arrived, Tuyizere was interacting with the group, but was quickly deterred by the team’s presence and lingered about 100 meters from the rest of the gorillas for the duration of the afternoon. Giraneza more than made up for Tuyizere’s reluctance with a constant onslaught of displays toward the group leader. The mammoth Inshuti responded with intimidating displays of his own and charged Giraneza multiple times throughout the data collection period.

Young female Nyandwe “was very interested in going with Giraneza” said Eckardt. "She was frequently looking at the lone silverback. Inshuti had the hardest time to move her up and away” from the intruder. Eckardt reported that the group leader was working hard to move his females higher up the mountain for most of the day, but Nyandwe took her time and was noticeably lagging behind. Eckardt observed one instance where Nyandwe was keeping an eye on both males. When she saw that Inshuti had moved higher up with the rest of the group, she started making her move towards Giraneza. But, Inshuti caught her and moved quickly back down to guard his female. Nyandwe feigned disinterest in the lone silverback and followed Inshuti back up to the group. And it wasn’t only Nyandwe that had an eye for Giraneza. Female Taraja was also very interested in going with him, but with her young offspring still in tow, she likely reasoned it wasn’t a good idea to attempt to transfer at this time.

Field Data Coordinator John Ndayambaje reported that Inshuti’s group was peaceful this afternoon and no lone silverbacks were found on their trail. Hopefully this will mark an end to the incessant intruders and Inshuti will have time to heal from his wounds.

To read more of the Fossey Fund blog, click here.

Silverback Leader Inshuti Attacked by Two Lone Silverbacks

Silverback Inshuti

Two lone silverbacks joined forces and attacked 24-year-old dominant silverback Inshuti today, reports Fossey Fund Field Data Coordinator John Ndayambaje. Inshuti sustained three large bite wounds on his head and one on his neck. Veterinarians Dr. Dawn Zimmerman and Dr. Jean-Felix Kinani (of the Mountain Gorilla Veterinary Project), along with a team of Karisoke trackers, will trek to the group tomorrow to assess the damage and potentially carry out a medical intervention. Karisoke researcher Winnie Eckardt, PhD., will join the team to collect behavioral data and fecal samples for her ongoing study on stress in the mountain gorillas.


Ndayambaje reported that the interaction began in the Tamu area between Mount Visoke and Mount Karisimbi at 11:24 a.m. and lasted almost 2-1/2 hours, until the pair of silverbacks retreated from the group at 1:49 p.m. The unidentified silverbacks displayed 19 times throughout the first half of the interaction, pushing Inshuti and his group to travel over 1.5 kilometers through the forest, in an attempt to get away from the intruders. Inshuti displayed three times before the physical interaction began, when he sustained the bite wounds.

With the absence of any other males in the group to help Inshuti, the three females, Shangaza, Taraja and Nyandwi, participated in the interaction in defense of their infants and injured leader. The two infants remained on their mother’s backs throughout the entire interaction -- which the field staff found particularly interesting because, at almost 3 years old, both offspring are at an age that they would not normally need to travel on their mothers' backs. Females Shangaza and Taraja reportedly charged the two silverbacks twice. On the first occasion, they charged both silverbacks jointly, causing the males to turn and retreat. Next, they charged only one of the silverbacks, at which point, the other male charged the females, who then retreated. During this time, Inshuti attempted to display, but was too weak to chest beat and was only able to display with hooting vocalizations. Inshuti group trackers report that the pair of silverbacks are 350 meters away from the group at this time. Inshuti is said to be in critical condition and appears to be in quite a lot of pain.

Although the attackers are not yet officially identified, the field staff believes these two silverbacks could possibly be 15-year-old Gushimira and 14-year-old Twihangane, the gorillas that dispersed from Pablo group on August 16. However, there are currently six lone silverbacks that are monitored by the Karisoke Research Center in this area and realistically, the aggressors could be any of them. Along with the medical intervention team for Inshuti, another team of trackers will enter the forest tomorrow morning to track the silverbacks and attempt to identify the individuals.

Gorilla Program Manager Veronica Vecellio says that “this is not the first time that Inshuti has been involved in such an aggressive interaction -- he suffered serious wounds from both Beetsme and Pablo (late silverbacks) in the past. He is a strong individual and he will likely bounce back from this.”
Our Karisoke staff is, of course, enormously concerned and hopes that Inshuti will recover from these injuries. Without Inshuti, this group would be in disarray, with the two infants of the group in an extremely vulnerable position.

An account of tomorrow’s observations and possible medical intervention will be reported promptly.

Jessica Burbridge, Field Communications Officer