True foxes fall within the genus vulpes, and are therefore distinct from other species of canids also referred to as foxes. They are opportunistic feeders, eating what ever they can from small mammals and birds to carrion and fruit. Species of fox can be found on every continent except Antarctica, occupying habitats from the mountainous to the sandy. They range from the large and very successful red fox to the small Rüppell's fox. Quite often the tip of the tail is a different colour from the rest of the pelt.