Ants’ Capability of Adding Numbers of Identical Elements

Knowing that the workers of the ant Myrmica sabuleti can distinguish different numbers of elements and have a basic notion of zero, we here examine if they can add two numbers of identical elements seen simultaneously. As soon as after three training days, the ants could respond significantly more to the sum of 1 + 1, 2 + 1, 3 + 1, and 3 + 2 elements than to the two initial numbers of elements seen during training and to the wrong sums 3, 4, 5 and 6 respectively. Their ability in giving the correct response seemed to somewhat decrease with increasing numbers to add. Twenty-four hours after the removal of the initial numbers presented during training, the ants no longer responded essentially to the correct sum of these numbers.