Answer: A Tortoise

In 1968 Zond-5, an unmanned version of Soyuz 7K-L1 moon-flyby spacecraft was carried aloft by a Proton-K/D rocket; it became the first spacecraft to travel to the moon, circle it, and return back to Earth. In addition to performing this space exploration feat successfully, it also marked the first time an animal had ventured that far into space and returned safely.

Aboard Zond-5 were a pair of Russian tortoises, wine flies, meal worms, plants, seeds, bacteria, and other living matter. Despite a very rocky re-entry to Earth’s atmosphere and a rough splashdown in the Indian Ocean, the entire biological payload was successfully recovered, demonstrating that complex organisms could withstand the extended trip in space and a lunar flyby.