He sat down to watch my "feeding" but didn't seem particularly impressed, so I changed activities; I scratched my scalp noisily to make a sound familiar to gorillas, who do a great deal of scratching.

We routinely combed the gorillas' favorite feeding places in the saddle between Mounts Visoke and Karisimbi for poachers, and cut animal traps almost as soon as they were set out. One afternoon ...