Wildlife “Mug Shots”

By Lory and George Frame

	The zebra’s saddle area is easily seen from a distance.

To study wild animals, we scientists have to recognize individuals.

Can you tell one sparrow from another? Or, if deer come into your yard in winter, can you tell whether they are always the same individuals?

You recognize your friends by remembering their faces. Everyone knows that no two faces are alike (even identical twins) and that a person’s face doesn’t change overnight.

	This is a zebra's I.D. card made by the authors when they studied wildlife in Africa. Do you see Lacey in the photograph above?

As wildlife biologists, we have special ways of recognizing animals. When we study wild animals and need to tell one individual from another, we look for a feature that is permanent but varies among individuals.

It’s not so hard, once you know how. You probably are good at recognizing a pet dog or cat when it is among several others like it. Chances are that you know its distinctive coat-color pattern, or maybe you know it by a particular collar.

		Sometimes we get a picture of just part of a dog. Can you tell if Ranger is in the photo to the right?

In much the same way, we look for different features in each kind of animal, trying one or another until we find what works best. With rhinos, we use the shape of the horns. Zebras have different stripe patterns, as unique as our fingerprints. For African wild dogs and Alaskan black bears, we use the shape and color of the light-colored splotches on the coat. With cheetahs, we use the pattern of spots on the face, chest, and legs. For giraffes, we use the pattern of splotches on the neck. And with African lions, we use the pattern of whisker spots.

Don’t be fooled when a giraffe turns its head, because the shape and pattern of splotches might look a little different. Which of the two giraffes is the same as the one in the top photograph?

Sometimes it is difficult to tell the individuals apart, so the researcher puts something distinctive on the animal to make it look different. Salmon in a stream all look pretty much alike. When we studied them, we attached numbered plastic tags near their top fin. We kept track of a kit fox by using binoculars to read a numbered metal tag placed in his ear. We put brightly colored or numbered rings on the legs of birds to tell the individuals apart.

Whatever kind of animal we study, we make a catalog of all the individuals we see. Often, our most valuable tool in the field is our box of file cards. Each card bears the “mug shot” or drawing of an animal’s unique markings.

We go to all this trouble because to understand social behavior we must know which individual is doing what. Which individuals are the parents? Which animal is the boss? Which animals are new-comers to the area? How far do young adults go to find new groups to live in? We would know a lot less about animal behavior and ecology if we didn’t know the individuals.

Sometimes our study animals are like old friends. When we come across a familiar-looking animal and reach for the box of file cards, we often find ourselves thinking, “Say, haven’t I seen you before?”

Answers:
Lacey is the zebra whose head is fourth from the right. Ranger is in the group of dogs, with just his back showing. The giraffe on the right is the same as the one in the other photograph.