Soviet space dogs Belka and Strelka orbited Earth on Sputnik 5 and returned after 16 orbits

Belka and Strelka (1960)
Soviet space dogs Belka and Strelka orbited Earth on Sputnik 5 and returned after 16 orbits. They were not alone; mice, plants, and even insects went with them, and all survived. Their flight proved that complex organisms can live a long time in orbit, influencing faith in future human spaceflight.