Paula's question of how do we identify individual orangutans is a good one. In many ways, recognition is done as we do with people: it is the whole appearance which guides identity. As with chimpanzees, but unlike gorillas, orangutans have lots of individual differences. One of the features I find most useful is the "forehead bump" all orangutans have but whose shape and size varies. Other unique features are hair colour, hair patterns, body-size, moles and scars. Adult males (cheek-padders) are easy; they all have different facial patterns and pad shapes. You learn to tell adult females apart by their individual appearance. The group I find the hardest (and at times impossible) to identify are old juveniles – young adolescents; orangutans aged from around 5 - 10 all look very similar. You can not tell the sexes apart; they all still retain a youthful lightness to their skin and, quite frankly, appear identical! Only the Assistants who see them very frequently can tell them apart.

I hope the attached photos show what I am talking about:

Tata: She is a big female; eyes quite close together; dark hair crown.

Princess: She has a line running from her nose to under her right eye, otherwise she has a smooth face with a narrow, pointy forehead-bump. Her coat colour is dark.

Siswi: Obvious!

Tut: Tut is thin to the point of being gangly; she has a distinctive fringe and her face is very lined.

Uning: Obviously still a young adult; Uning retains the lightness around the eyes and mouth which is typical of young orangutans. Her eyes are also quite close together.

Badut: Compared with other adult males, Badut has a narrow face.

Kusasi: His cheek pads are incredibly ragged.

Masran: The join of his cheek-pads is very triangular and he has a notch on his left pad.

Tom: Like Siswi, when Tom is around you know it! However, the join between his cheek pads is distinctive. I describe it as “messy”. Compare it with the photo of Win and you’ll see what I mean.

Win: Has a very obvious crease running across his left cheek-pad.

Juvenile: Beat me! I can’t even tell if the orangutan in the photo is a boy or a girl :-)

Photographs by Anna Lewis, Hugh Sturrock, Melissa Tolley, Ursula Fuller and Stephen Brend.