The male silth plodded forward wearily at sixty miles an hour, pausing only long enough to uproot and wolf down one of the rare scrub trees directly in its path. Its three hundred tons of massive body shook the ground as the great hind legs thumped along, and every cell of it ached with hunger. It was warm blooded, despite its vaguely reptilian appearance. Only meat could satisfy its need for energy. But the great herds lay a thousand miles to the north of this barren land. Inside the silth, the