Biology professor Andrew Poyarkov thinks that stray dogs in Moscow have learned to use the subway to get around the city. He thinks they are using the rails in the morning to get to the center of town were food is more plentiful before returning to where they live each evening. "They do not just go to the subway station, they actually board the trains. They seem to have learned how long they need to stay on the train to leave at the right station. Sometimes they fall asleep and miss their stop. Then they get off take another train back to the center," he says.