"Sixteen feet if it's an inch," he decided. "Nonsense," he went on, with
a tone of relief in his voice. "There's nothing that walks on four feet
could do it. A horse even couldn't stand on his hind legs and strike with
his fore hoofs the place where those scratches begin. Some of those
pre-historic monsters, whose skeletons we see in the museums, might have
done it, but nothing that walks the earth nowadays. You'll have to guess
again, Bert."

"They might have been made by some animal in climbing," suggested Dick.
"He might have slipped in coming down and torn off those strips in trying
to hold on."

"But grizzlies don't climb," objected Bert.

"Who said it was a grizzly?" retorted Tom. "It might have been a black or
brown bear. You've got grizzlies on the brain. The very biggest don't
measure more than nine or ten feet from the nose to the root of the tail.
Allowing a couple of feet more for his reach, and you have eleven or
twelve altogether. How do you account for the other four or five?
Unless," he went on with elaborate sarcasm, "you figure out that this pet
of yours is about fourteen feet long."

The argument certainly seemed to be with Tom, but Bert, although he had
no answer to it, still felt unconvinced.

"The scratches are too deep to have been made by any animal slipping," he
persisted. "The beast, whatever it was, had a tremendous purchase to dig
so deep. And he couldn't have got such a purchase except by standing on
his hind legs."