Elephants are among the most intelligent, socially intricate and emotionally complex non-human species - or so holds conventional wisdom. This generally held conviction is based on legend as well as on decades of scientific research.
For almost two thousand years biologists and philosophers going back to Aristotle have viewed elephants as highly intelligent and some have even seen them as quasi-moral agents. The literature is full of accounts describing the apparent intelligence of elephants. For example, one often related tale is that of Chadrasekhan, the elephant who would not lower a pillar of wood into a hole containing a sleeping dog until the dog was chased away. Another account is that of an elephant who placed vegetation under his feet to prevent himself from sinking into muddy ground where he was tied and could not reach dry ground. Yet another legend tells of captive elephants who stuffed their bells with vegetation so that they wouldn't ring when they entered the farmers' fields at night.
Rench, a scientist who studied elephant intelligence remarked on the surprising ability of captive elephants to work with minimal instruction as well as their talent to function as a team. Their extraordinary balance and synchronization, pushing and dragging heavy logs onto a truck, for example, caused him to credit elephants with the ability to anticipate what will come of certain actions.
Many of the accounts of elephants' cognitive abilities appear to be so astonishing that it is surprising that until very recently there has been so little scientific follow up. Just how clever are elephants?
http://www.elephantvoices.org/elephant-basics/elephants-are-intelligent.html