Forward, leap! In single file, a troop of colobus monkeys jumps and swings its way home through the upper canopy of the tall trees in Mount Kilimanjaro's tropical forest belt. It is late afternoon, the time when the monkeys journey from their daytime eating trees to their sleeping trees. A big male leads the way, his perpetually grim face focused ahead on the branches of the next tree. He pushes off with his hind feet, swan dives through the air with the breeze under his cape and tail, nosedives to catch a branch with his mitten-like front feet, gathers his energy, and springs again.

Close behind are four females, one with a baby clinging to her front, followed by two sub-adults and a juvenile. The average group size for the Angolan variety of Colobus, the type found on Kilimanjaro, is nine. All but the pink-and-white baby are sturdy, pot-bellied monkeys with jet-black fur everywhere except their tails and capes, which are brilliantly white. They scowl from gray faces, eyes set deep under overhanging brows, wide mouths straight and serious over their bulky chins. In the morning, their raucous chatter reverberates through the mist. Later in the day, hikers on the mountain may hear rounds of song as one group of Colobus starts the music and another group, perhaps far in the distance, picks it up and passes it on.

It's a tough life, being a colobus. After their morning wake up call, the monkeys travel to forage trees where they spend the day on the highest branches capable of supporting them, eat leaves which may be poisonous to other species, groom each other's luxurious fur, and sunbathe. A strenuous nap after lunch, an afternoon snack, and some much-needed relaxation complete the schedule. It's no small feat to gobble up 25-33% of your body weight in leaves, but that's what the average colobus, reaching a mature size of 20-32 pounds and 21-28 inches for males, 14-22 pounds and 19-26 inches for females, needs every day.