The brain can weigh 4.5 – 5 kg – larger than any other land mammal and only twice smaller than the brain of whales, which weigh 20 x more than elephants. A wide variety of behaviour, including grief, play, use of tools, compassion, self-awareness and the best memory in the entire animal kingdom is evidence of a highly intelligent species rivalled only by dolphins and primates. Increased beyond comparison, the temporal lobe, responsible for processing of audio information, hearing and language, is larger than that of dolphins (which use elaborate echolocation) and humans (who use language and symbols).
Elephant eyes are far larger than human eyes, almost 5 cm in diameter. In bright sunlight elephants tend to travel with their eyes half hooded but where there is shade or shelter the eyelids are nearly always open wide. The pupils zoom in and out in direct relation to the emotional value of what is being seen. Because of the size of the skull, the distance between the elephants eyes is huge – they lie right on the edge of the orbit. This means that even though an elephant has little ability to turn its head, it has surprisingly good rear-view vision. To see forward and get any kind of binocular vision, an elephant must raise its head and look down its nose.
In low light at least, elephant eyesight is quite good – they have all the necessary retinal and optical equipment In addition to their 2 protective eyelids, elephants have a third nictitating membrane that sweeps horizontally across the eyeball, lubricated by the hardevian gland. The secretion from this gland differs slightly from that of the human’s lactrymal gland, which produces tears, but when there is enough of this secretion, something similar to tears trickles down an elephant’s face.
African elephants have the largest ears in the world, measuring up to 2 m from top to bottom in a large male bull, weighing up to 20 kg. This increased size helps the elephant lose more heat in the hotter tropical climates. African elephant ears are three times bigger than those of Asian elephants.
The ears are the main organs used for thermoregulation and heat loss. Flapping the ears cools the body like a fan, while also circulating cool air over the blood vessels and so cooling the blood. The skin on the back of the ears is very thin, for this purpose. Blood flows through a network of veins on the back of the ear at a rate of 5-12 litres per minute. Three-quarters of heat build-up is lost through the ears, water and evaporative cooling are responsible for the rest.
Each elephant’s ear is unique and is used as a type of fingerprint for identification in the wild.