One gorilla twin has died

Fossey Fund staff are extremely saddened to report that one of the young mountain gorilla twins born to mother Isaro in January has died, due to injuries sustained during an interaction with another group.

On Thursday afternoon, our trackers heard an auditory interaction between the twins’ group (led by silverback Isabukuru) and another group. Immediately after hearing the other group, Isabukuru stood up and began to move his group away. This was excellent leadership by Isabukuru, given that interactions between groups can be quite aggressive, and infants, unfortunately, are often targeted. After traveling for a period of time, Isabukuru’s group began to rest, suggesting they were comfortable with their distance from the other group.

Isaro with twins

When our trackers arrived on Friday morning, they found that the two groups had come together at some point later on and that one of the twins had been fatally injured during the interaction. Mother Isaro was carrying it, along with the other twin, whose condition was fine.

Silverback Isabukuru, known for his low tolerance of human observers, was extremely stressed out and aggressive toward the trackers. However, we will continue to monitor the group and hope that they will be able to carry on normally.

We know from our long-term studies that approximately 20 percent of infants do not survive their first year of life. However, we were hopeful about the future of Isaro’s twins, since they are now almost 7 months old and had done so well up to this point. They still survived longer than the other two sets of twins recorded at Karisoke during our nearly 50 years of monitoring.

Photo by Jordi Galbany