When the sun plunged into the masses of yellowish mist that clung to the rim of the crater a bright moon was already high in the heavens. The transformation from day to night was sudden, for in the tropics the light fades abruptly, and darkness swoops upon the land almost as a black cloud scurrying across the face of the sun obliterates the brilliant radiance in a short space of time.
The soft moonlight, in streaks and splashes, and the long, creeping shadows made the floor of the crater seem weird and unreal. A streak of silvery light lay across the smooth surface of the lake, and as the two men, crouching on the narrow ledge, gazed in fascination at it, the mirror-like water was broken by ripples that appeared here and there like little pools and lines of sparkling jewels. The creatures that were coming out for their nocturnal frolic, but which could not be clearly distinguished, swam in circles or straight lines and dived with great splashes. Only their heads, like black dots, could be seen on the surface of the water.
“They may be some kind of a muskrat, like the nutria of the Argentine, or like the water opossums,” Stanley suggested. “Whatever they are, they do not seem to be afraid of anything, for, look, one is heading for the shore.”
“I suppose the tigers don’t bother them; they are too small to make even a mouthful.”
A herd of very large, black animals, with low-swinging heads and short, curved horns suddenly hove into sight. They emerged from a clump of forest in a long, straggling formation, and moved to the centre of the largest clearing.
“Buffaloes,” Stanley gasped. “A herd of buffaloes. But what are they doing out in the open?”
“I should think they would hide at night, like the other animals we saw. But they do not seem to be worrying about anything.”
A shrill wail rose clear and piercing from somewhere in the darkness and echoed back and forth among the rocky walls. It was not repeated.
“That sounds like a puma,” Ted hazarded after listening in vain for a repetition of the cry. “I wonder what next!”
Just then one of the buffaloes gave a sharp bellow of alarm. The herd became charged with life instantly, and rushed into a compact mass so quickly it was impossible to follow their movements. But when they again became quiet it was seen that they were standing in a solidly packed circle. The cows and calves were in the centre, and the males, facing outward with lowered heads and bristling horns, formed an unbroken stockade around them.