The Drills are losing their forest...
The Drill is a large monkey that lives in the forests of Africa. They live in packs of 20 to 30 monkeys. Sometimes the packs assemble into large herds of more than 200 monkeys. Over the last 30 years, the Drills' numbers have diminished to less than half of their previous existence. There are two main reasons for this. One is the disappearing forest. Not only have Drills lost a place to live, farmers kill them because they eat crops growing in what was once their homes, further reducing their numbers.

Damages of hunting
The other reason is that Drills are being hunted for food. Characteristically, a pack of Drills lives by observing various rules and roles, much like our human society. And like humans, where the loss of a team, group, or family member can create instability, Drills also find it hard to regain stability amongst themselves. This is why hunting does more than just reduce the number of the Drills; it causes irreparable damage on the pack.