If you have a mixed breed and you want to try to guess his ancestry, you can work on the problem from two ways. One is by studying his conformation. You can say: "He looks like . . ." And the second way is observing his actions. You can conclude that "he acts like . . ." You'll probably never know the truth, but you can have some fun, and you'll understand dogs better while doing it.

Scientists often catalog dogs by their jaw lengths. There are long-jawed breeds such as the Doberman Pinscher, German Shepherd, Greyhound, English and Irish Setters, and others. And there are short-muzzled dogs, such as the St. Bernard, Chow Chow, Chihuahua, Pomeranian, and others.

With some of these breeds, such as the Doberman Pinscher and the German Shepherd, there is a tendency, which is inherited, to be minus some of their premolars. Thus, the jaw length, plus the absence of teeth, might give you a clue. Do not confuse the short nose or short jaw with the pushed-in face of such breeds as Pekingese, Bulldogs, and Boston Terriers. These are difficult features to keep, even in purebreds. In mixed breeds the pushed-in face seldom is seen, though it may be slightly discernible in crossbreeds.

The ears also may be a clue. Spaniels and Poodles have longer than normal ears. So do Bassets and Bloodhounds. It is not known for certain, but it is believed that all prehistoric dogs had erect ears such as wolves, jackals, foxes, and hyenas have. So erect ears might indicate shepherd dog ancestry of some kind, or Arctic sled dog, or Chow blood. Drooping ears could indicate Spaniel, Poodle, or hound ancestry.

Some dogs, with very fine, short coats, become nearly hairless. This does not indicate Mexican or Chinese Hairless ancestry. More likely it is a little-understood disease called alopecia, or falling hair. But hair type can give you a clue.

Long, standoffish guard hair is a characteristic of the Chow Chow, and of many Arctic dogs. Long bristles that lie flat indicate some of the shepherd types. Hair which has a tendency not to fall out, but to get frizzy and curly, could indicate some terrier blood. Very short, fine hair is a characteristic of Dachshunds, Whippets, Miniature Pinschers, and similar dogs. The presence of a strong spotting pattern would indicate Dalmatian ancestry.

That ancient first ancestor of the dog, Miacis, had a long back. Dog people have been trying to breed out this tendency in most breeds for a very long time. German Shepherds are longer in body than they are tall. So are Dachshunds, Welsh Corgis, and a few others. A long-backed, short-legged, drop-eared dog would indicate Dachshund blood. If he had the first two characteristics, but erect ears, he might easily have some Corgi blood in him.

And now consider the possible ancestry of your dog just by studying hr actions. Dogs that chase cars, bicycles, and running children inherit strong herding or cattle-driving instincts. The cattle-driving instinct is especially strong if the dog nips at the heels, without really trying to bite.

Some dogs grab and shake when trying to kill some creature or while fighting. This is a strong terrier instinct—the centuries-old methods of the great ratter. Dogs inheriting Greyhound instincts slash with their teeth, and duck in and out like great prize fighters. They also love to get out and run, whether or not they are chasing something.

In fighting, some dogs grab, then begin to chew while holding on, trying to get more of the enemy into their jaws. This is a habit developed hi the Bulldogs and other pit-fighting dogs of the past. So if your dog shows such tendencies, he might have Bullterrier or Bulldog blood in him.

If, while out in the field, your dog tests wind scents instead of trailing foot scents (tracking), then he might have Setter, Pointer, or Spaniel blood in him. If he tracks, then he should have some hound ancestry. If he's crazy about jumping into cold water and just swimming about, he probably has Spaniel, Poodle or Retriever ancestry.

All these clues can make owning a mixed breed a lot of fun. You might even make a catalog of all the traits your dog shows. And in that case, you'd really find that your dog is ALL dog.