We usually see these monkeys on treetops and were really surprised to see him running through the open savannah of the Masai Mara that too when there was a pride of lion nearby. We on the border of the Masai Mara and a Conservancy with a pride of lions as they were resting under some shade from the midday sun. From afar we saw something running on the ground completely in the open with no tree in sight and we approached to find this out of place vervet.