"I guess it was the mastodon that did the hunting in those days," Dick answered. "The cave-men were not the hunters but the hunted, if you ask me."

"And that goes for the sabre-toothed tiger, too."

"I bet it was a toss-up whether the human race would conquer the animals or be eaten by them in the Stone-Age," said Dick. "Maybe that's why the people of today get scared and have panics so easily. It may be a hang-over from the fear that haunted our ancestors."

"I can't say I'm exactly scared——" Dan Carter began, but before he could finish his sentence a shout from a boatman startled him and he answered with a yell of terror.

The canoe was passing close to a shallow spot and suddenly a pair of jaws snapped open right alongside. They were so wide that it looked as though they could crash through the canoe with one bite, and the vicious rows of teeth could easily slice through a man's body.

Dan thought he was facing a horrible death in that instant and in fact he had never had a narrower escape. As he yelled, he threw himself flat, but the black guide, Mutaba showed no sign of fear.

Mutaba had hunted crocodiles before and knew what to do. His black arm shot out like lightning with a heavy stick in his fist. It was sharpened at both ends and as Mutaba thrust it upright between the monster's rows of teeth and the jaws snapped to close, the upper and lower jaw were stuck on the points of the stake.

Mutaba grinned as he jerked away his hand and the canoe darted past, just in the nick of time, for the enraged monster thrashed about with his tail, churning the muddy water to foam.

The man-eater was trapped.

The harder he struggled, the more firmly he impaled his open jaws upon the sharp stick, and all his thrashing about was futile, for the following boats sped by close to the opposite bank.