Belka (Белка, literally, "Squirrel" or alternatively "Whitey") and Strelka (Стрелка, "Little Arrow") spent a day in space aboard (Sputnik 5) on 19 August 1960 before safely returning to Earth.
They were accompanied by a grey rabbit, 42 mice, two rats, flies and several plants and fungi. All passengers survived. They were the first Earth-born creatures to go into orbit and return alive.