Root cropping by pocket gophers

Pocket gophers (Geomys spp.) are solitary, root-eating fossorial rodents native to North and Central American grasslands and are presumed to acquire most of their food through excavation of tunnels maintained as part of tunnel systems up to 160 m long1,2. Given that burrowing is 360–3,400 times more energetically costly than surface walking, pocket gophers have high energy requirements3. Roots are scarce at the depths of their tunnels in the sandy soil of our study site (20–64 cm), but here we describe a novel food source for southeastern pocket gophers (Geomys pinetis, hereafter gophers): roots that grow into their tunnels. These roots could supply an average of 21% but up to 62% of their daily basal energetic needs. Roots grow into the humid interiors of Geomys pinetis tunnels where they benefit from nutrients from gopher wastes. Cropping these roots supplies G. pinetis with an average of 21% but up to 62% of their daily basal metabolic needs. This behavior may qualify these fossorial rodents as the first non-human mammalian farmers.z