Dogs performed worse than wolves
Range and her colleagues compared the results of the wolf test with those from the dog test. The comparison showed that dogs were unable to discriminate between difficult comparisons such as two pieces of food versus three or three pieces versus four. The wolves, in comparison, fared much better. “Dogs are better able to discriminate the quantities of food when they can see them in their entirety,” says Range. “But this requires no mental representation.”
via Testing numerical competence in animals | Science Codex.