In the last 80 years, 40 million hectares of grassland (roughly the size of Montana, or Germany and Switzerland combined) have become overgrown by the Acacia bush.

A blue bush acacia. (Dania Maxwell / Los Angeles Times) Plants including foxtail agave, Cleveland sage, common yarrow, California buckwheat and bush monkey flower grow alongside a path.

Surprise! It's the ants in the acacia that keep the grasslands healthy. Dino Martins. I asked a group of new millennials—the generation born in the 1980s and later—how the Smithsonian might ...

Bush babies are found in forests throughout sub-Saharan Africa. Some species, like the South African galago, hang out in acacia trees on the savanna.