Subterranean rodents spend most of the day inside underground tunnels. where there is little daily change in environmental variables. Our observations of tuco-tucos (Ctenomys aff. knighti) in a field enclosure indicated that these animals perceive the aboveground light-dark cycle by several bouts of light-exposure at irregular times during the light hours of the day. https://www.roneverhart.com/Bob-The-Boxcutter-R1P-Aluminum-Grey/