the ones i know are so well known, i feel i am wasting your time..

Whales: modern scientist find that whale have distincive tail fins. to identify individuals, they look at their tails

Zebra tend to have slightly assymetrical stripes, the right side, is the one that is used to identify them.

and in human, several 'characteristics' remain largely unchanged from infancty to adulthood, the folds and shape (lobed/not lobed) are one of the most obvious.
(ear are also use as 'visual indicators' for infants health.
some kidney, heart and other internal disorders can be diagnosed/predicted/indicated by how the ears are form, and by how they are positioned on the head.)

personally i got to know all the elephants at the bronx zoo (a small herd of 15) by looking at their ears..
Tus (one of the matriarchs) had very symetrical ears.
happy and grumpy, (twins!) were easy.. happy had very similar patches of pink skin on both ears, (a pair of pink earings) grumpy had one ear almost fully dark, and one ear with a pink patch.. (she was missing an 'earing'--various other 'flags' or patches of different color pigment, small detail about the shape of the ear could be used for all the elephants.

we went to the zoo about 3 to 4 times a year, and one of the elephant keepers was impressed at how many elephants i had learned 'by name'. i don't know how they keepers kept track by ears worked for me.


my other obsession