Complex sentence: Unlike the closely related guenons, vervets are not primarily forest dwellers, rather, they are semi-arboreal and semi-terrestrial, spending most of the day on the ground feeding and then sleeping at night in the trees.
Split into simpler sentences: Unlike the closely related guenons, "Chlorocebus" species are not primarily forest dwellers. Rather, they are semi-arboreal and semi-terrestrial, spending most of the day on the ground feeding and then sleeping at night in the trees.