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.

Group Leader Isabukuru Turns on Beta Male

Isabukuru fought Kubaha Monday, reported Karisoke Research Assistant Jean Paul Hirwa. The researcher noticed that Isabukuru was clearly uncomfortable with Kubaha’s presence yesterday morning when the field staff arrived at the group, and the dominant male was keeping a close eye on the beta male. Kubaha lingered about 10 meters from the group for a short while before Isabukuru confronted him.

When Isabukuru approached Kubaha, the beta male “pig grunted” towards him in warning, but Isabukuru advanced on him, initiating a short bout of “kick-hits." It was clear that Isabukuru had “defeated” Kubaha when the dominant silverback had him pinned to the ground screaming, with Kubaha assuming a cowering posture. Kubaha attempted to make his escape, but Isabukuru held him down, mouth open wide and teeth poised above his opponent. The females of the group were equally aroused and Ikaze bit Kubaha in a moment of excitement.

Isabukuru rounded out the incident with a vigorous display towards Kubaha, then “kick-hit” him before allowing him to go. Kubaha immediately started moving away from the group and was feeding very far from Isabukuru’s group when the observation and data collection period came to a close. The Fossey Fund field staff was unable to detect any serious injuries on Kubaha, however a wound was seen on his right arm from Ikaze’s bite. Karisoke researcher Stacy Rosenbaum made plans to trek to the group the next day to collect data and report on the group dynamic. More to come.