Any species can benefit from being able to measure quantities. Knowing how much food is available or if your gang is outnumbered are examples of how important the skill can be. Researchers have discovered that wolves are better than dogs at discerning quantities.

Researchers from the Messerli Research Institute at the Vetmeduni Vienna believe that dogs lost this skill during domestication, according to Lions and hyenas will only fight trespassers if their group outnumbers the intruders.

Friederike Range and Zsofia Virányi created a study in 2012 in which pieces of cheese were put in tubes for the animals. The animals did not see the human put the cheese in the tubes. By pressing the correct buzzer, the dogs got their tasty reward.

"We deliberately performed the test in such a way that the dogs never saw the full quantity of food at once," Range said. "We showed them the pieces sequentially. This allows us to exclude the possibility that the dogs were basing their decisions on simple factors such as overall volume. The dogs had to mentally represent the number of pieces in a tube."

When the wolves were tested, they performed better than the dogs. The dogs could not differentiate between two, three or four pieces of cheese, according to

"Dogs are better able to discriminate the quantities of food when they can see them in their entirety, but this requires no mental representation," Range said.

"Compared to wolves, domestic dogs no longer have to search for food on their own. They have a secure place to sleep and even mating decisions are made by people. Dogs are thus excluded from natural selection," Range explained. 

The results were published in the journal "Frontiers in Psychology."