And if one of these animals went from the Bering Strait to the Davis Strait, it's quite simply because there's some passageway from the one sea to the other, either along the coasts of Canada or Siberia."
Si uno de estos animales ha pasado del estrecho de Bering al de Davis es, simplemente, porque debe existir un paso de un mar a otro, ya sea por las costas de América o por las de Asia.