"What do you think we'd better do?" asked Ned. "This is getting
serious."

"What is? Oh, the steers. Why, they are getting a little too close,
aren't they?"

They were, for a fact, and the animals in the foremost ranks, catching
sight of the little party on the hill, broke into awkward gallop. As
far as the boys could see, they beheld nothing but waving tails,
heaving heads, armed with long sharp horns, and the movement of brown
bodies, as the thousands of steers came on with a rush.

"We'd better--" began the professor, who was walking slowly along, his
eyes fixed on the ground, in search for another of the queer bugs.
"Look out!" he suddenly cried. "Stand back boys!"

Hardly had he spoken than there sounded, high and shrill above the
dull rumble of the oncoming cattle, a queer, buzzing noise.

"Rattlesna " exclaimed Ned.

"Yes, a whole nest of them, in a prairie dog's hole," added the
professor. "I nearly stepped into them. There must be thirty or
forty."

The boys looked to where he pointed. There, in a sort of depression,
near a little hollow, on the edge of what is called a prairie dog
village, they saw an ugly wiggling mass, which, as their eyes became
more used to the colorings, was seen to be a number of the deadly
rattlesnakes.