Lower population levels and the absence of large-scale agriculture mean that many species exist which are extinct on the gliksin version of Earth. These include not only birds such as the passenger pigeon, but also megafauna such as the woolly mammoth. Also, forests are much more extensive because there was no need to cut them down on a large scale. Barasts have domesticated wolves as companions, but have not bred them into the many varieties of the domestic dog. A gliksin may become fearful upon seeing a barast dog, thinking it a wild wolf. A barast, seeing a gliksin's dog such as a dachshund, may wonder if the creature really "is" a dog.