Abstract
Japanese tree frogs (Hyla japonica ) were sent to the MIR station and spent eight days in orbit in December, 1990. On the MIR, floating frogs stretched four legs out, bent their bodies backward and expanded their abdomens. Some frogs showed tumbling. On a surface of something, more than half of frogs bent their neck backward, pressed their abdomens against the substrate with relaxation of their hindlimbs, and walked backward. This behavior was observed on parabolic flights and resembles the retching behavior of sick frogs on ground. The frequency of failure to land after a jump decreased in the later observation period. This result suggests that frogs could adapt to microgravity. Behaviors ofthe flight frogs became normal as early as 2.5 hours after landing.
