This beautiful article sheds new light on brain development related to use of tools. The authors trained these adult rodents to use a T-shaped rake as a hand tool and then measured neurogenesis in the dentate gyrus of their hippocampus. They found that the proportion of new synapses formed in the CA3 region of the hippocampus after this training was greatly increased, much more than after training in a radial maze, a classical procedure not involving the use of external tools. This article thus emphasizes the interest of further studying, in other animal species, as well as in humans, the likely relation between use of tools and brain development. This, at the end, might shed new light on the implications of neurogenesis in areas of the human brain in relation to the technological abilities of human beings.