What caused the decimation of the world's rarest great ape population?

The world’s rarest great ape population almost disappeared because they lost their home and got hurt by people.

Imagine you have a favorite playground, that’s like the home for these apes. One day, some people start cutting down all the trees in the playground to build houses and roads. The apes don’t know what's happening at first, but soon they can't find enough food or safe places to sleep.

Then, some people come with loud noises and hurt the apes, like when you get scared by a sudden bang in your room. This makes it harder for the apes to have babies or stay alive.

Also, sometimes these apes get sick from things we give them that they don’t understand, like medicine we use for humans, but it's too strong for them.

So, all of these problems together made their numbers go down a lot, just like if your favorite playground turned into a busy street with no trees or swings.