In 2005, NASA flew five thick-toed geckos aboard Foton-M2 for 16 days without food or water; all were recovered with no apparent negative health effects

Five geckos orbited Earth for sixteen days without food or water. Researchers studied how weightlessness affects these cold-blooded animals. Bone tissue loss occurred in geckos and a ground control group. This indicated fasting and enclosure conditions caused the bone loss. Subsequent missions provided food and water to prevent these changes.