Thomas Pynchon, Gravity's Rainbow page 614

One village in Mecklenburg has been taken over by army dogs, Dobermans and Shepherds, each one conditioned to kill on sight any human except the one who trained him. But the trainers are dead men now, or lost. The dogs have gone out in packs, ganged cows in the fields and brought the carcasses miles overland, back to the others. They've broken into supply depots Rin-Tin-Tin style and looted K-rations, frozen hamburger, cartons of candy bars. Bodies of neighboring villagers and eager sociologists litter all the approaches to the Hund-Stadt. Nobody can get near it. One expeditionary force came armed with rifles and grenades, but the dogs all scattered into the night, slender as wolves, and no one could bring himself to destroy the houses and shops. No one wanted to occupy the village, either. So they went away. And the dogs came back. If there are lines of power among themselves, loves, loyalties, jealousies, no one knows. Someday G-5 might send in troops. But the dogs may not know of this, may have no German anxieties about encirclement--may be living entirely in the light of the one man-installed reflex: Kill The Stranger. There may be no way of distinguishing it from the other given quantities of their lives--from hunger or thirst or sex. For all they know, kill-the-stranger was born in them. If any have remembered the blows, the electric shocks, the rolled-up newspapers no one read, the boots and prods, their pain is knotted in now with the Stranger, the hated. If there are heresiarchs among the dogs, they are careful about suggesting out loud any extra-canine source for these sudden eruptions of lust to kill that take them over, even the pensive heretics themselves, at any first scent of the Stranger. But in private they point to the remembered image of one human, who has visited only at intervals, but in whose presence they were tranquil and affectionate--from whom came nourishment, kind scratches and strokings, games of fetch-the-stick. Where is he now? Why is he different for some and not for others?