A review of the ecology, behavior, and cognitive capabilities of crawfish frogs (Rana areolata) with the goal of restoring extirpated populations

Throughout much of the twentieth century, the biology of highly secretive Crawfish Frogs (Rana areolata) was unknown or misunderstood, with partial observations of behavior and ecological interactions producing contradictory facts and conclusions. Beginning in 2000, this situation began to resolve: the species’ status was clarified, and reliable demographic data were collected, but most questions about Crawfish Frog natural history and life history remained unanswered. In 2009, the Indiana Department of Natural Resources asked us to determine the causes of state endangered Crawfish Frog declines and to recommend management efforts to prevent statewide extirpation. We employed a combination of conventional wildlife biology techniques, including drift fence-pitfall trap arrays to determine demographic patterns, radiotelemetry to monitor movement patterns, and statewide call surveys to assess status. In addition, once we understood the relationship of Crawfish Frogs to crayfish burrows, we pioneered the technique of employing wildlife cameras on occupied burrows to observe seasonal activity patterns. We also conducted disease surveys, measured ontogenetic series to determine patterns of body growth, teased out differences between upland and breeding calls, extended our statewide distributional surveys to encompass the species’ entire 13-state range, and working with the Detroit Zoological Society developed head-starting protocols to circumvent high larval mortality. Further, using this information we inferred the cognitive capabilities (including memory and temperament) of this species. The goal with these studies was to gather the information necessary to inform management decisions to restore Crawfish Frog populations to their historical mid-continental range. Crawfish Frogs require high-quality native prairie or old-field upland habitats when not breeding and fishless seasonal and semipermanent wetlands for breeding. But Crawfish Frogs will not occupy these otherwise desirable sites unless they also feature a high density of vacated crayfish burrows. Crawfish Frogs use these burrows as a buffer against environmental extremes and employ them as a component of their behaviorally and morphologically specialized strategy of predator defense. Finally, we detail how we have applied this knowledge to sites that currently support, formerly supported, and could possibly support Crawfish Frog populations to guide restoration practices that would return this species to its historical range and secure its future.