Everyone knows that elephants are clever but science is only now beginning to reveal just how smart they are.
Andrew Luck-baker joins British and Kenyan researchers on the East African savannah who are revealing the depths of the elephant mind with the help of a huge loudspeaker in the back of a Land Rover.
By playing different sound recordings (of elephants, lions and people) at elephant family groups, the scientists are probing the sophistication of elephant memory and pachyderm numerical skills.
They are also testing whether elephants can distinguish between different human languages.
Anecdotes suggest they can.
Another team of British researchers have been using urine samples and smelly clothes in other experiments to probe the agility of elephant grey matter.
All this has been taking place on the plains of Amboseli National Park in Kenya, under the looming presence of Mount Kilimanjaro.
Amboseli is home to the world's longest running study of a single elephant population.
Started by journalist-turned-biologist Cynthia Moss almost forty years ago, the study is a continuing record of every facet of the lives of every elephant living there.
Cynthia Moss says the Amboseli data is like "gold" for the visiting animal psychologists to make sense of their experiments.
It turns out that that elephants are more intelligent than humans in some respects.
For example, elephants have a much better short-term working memory than we do and out-perform people on at least one numerical skill.
But why might they need to distinguish between the English language and the language of the local Masaai people? And what does this research tell us about the evolution of animal intelligence in general?
On the African plains, science reveals the secret agility of the elephant mind.