<P> Elephants use some vocalisations that are beyond the hearing range of humans, to communicate across large distances . Elephant mating rituals include the gentle entwining of trunks . </P> <P> While feeding, elephants use their trunks to pluck at leaves and their tusks to tear at branches, which can cause enormous damage to foliage . A herd may deplete an area of foliage depriving other herbivores for a time . African elephants may eat up to 450 kg (992 lb) of vegetation per day, although their digestive system is not very efficient; only 40% of this food is properly digested . The foregut fermentation used by ruminants is generally considered more efficient than the hindgut fermentation employed by proboscideans and perissodactyls; however, the ability to process food more rapidly than foregut fermenters gives hindgut fermenters an advantage at very large body size, as they are able to accommodate significantly larger food intakes . </P> <P> African elephants are highly intelligent, and they have a very large and highly convoluted neocortex, a trait they share with humans, apes and some dolphin species . They are amongst the world's most intelligent species . With a mass of just over 5 kg (11 lb), elephant brains are larger than those of any other land animal, and although the largest whales have body masses twentyfold those of a typical elephant, whale brains are barely twice the mass of an elephant's brain . The elephant's brain is similar to that of humans in terms of structure and complexity . For example, the elephant's cortex has as many neurons as that of a human brain, suggesting convergent evolution . </P> <P> Elephants exhibit a wide variety of behaviors, including those associated with grief, learning, allomothering, mimicry, art, play, a sense of humor, altruism, use of tools, compassion, cooperation, self - awareness, memory and possibly language . All point to a highly intelligent species that is thought to be equal with cetaceans, and primates . </P>

What is the length of an african elephant