Multi-opening burrow systems constructed by prairie dogs (Cynomys) ostensibly provide escape routes when prairie dogs are pursued by predators capable of entering the burrows, such as black-footed ferrets (Mustela nigripes), or by predators that can rapidly dig into the tunnels, such as American badgers (Taxidea taxus). Because badgers also prey on ferrets, ferrets might similarly benefit from multi-opening burrow systems. Using an air blower, white-tailed prairie dog (Cynomys leucurus) burrow openings were tested for connectivity on plots occupied by black-footed ferrets and on randomly selected plots in Wyoming. Significantly more connected openings were found on ferret-occupied plots than on random plots. Connected openings might be due to modifications by ferrets in response to plugging by prairie dogs, due to selection by ferrets for complex systems with multiple openings that are already unobstructed, or simply due to ferrets lingering at kill sites that were multi-opening systems selected by their prairie dog prey.