Spatial familiarity in the blind cave crayfish, Orconectes australis packardi

This study examined behaviour of cave-adapted blind crayfish to novel territories of various sizes. Cave crayfish, Orconectes australis packardi, were kept within a dark room in individual aquaria for 7 days. They were then placed into a small tank (33 × 28 × 23 cm, 10-15 cm water depth), and a large tank (54 × 37 × 30 cm, 10-15 cm water depth). Time, distance of movements, and length of pauses were recorded. Upon initial placement in a new setting, crayfish will walk around the perimeter where their antenna can contact the side of the tank. The animals will subsequently move around the tank away from the perimeter, or they will begin to dig a burrow. Familiarity within the environment for an individual crayfish was defined as when the animal initiates digging or remains in one place for over 5 minutes. The study demonstrates that time required to become familiar to a new setting depends on the size of the setting. The authors suggest that a balance between sensory input and inner processing, termed "familiarity", can be reached.