Aug 19: Belka and Strelka (Russia)
http://en.wikipedia.org/wiki/Soviet_space_dogs
Belka (Белка, literally, "squirrel", but as a dog's name most likely means "Whitey", from Russian: "белый" (for "white")) and Strelka (Стрелка, "Arrow") spent a day in space aboard Korabl-Sputnik-2 (Sputnik 5) on August 19, 1960 before safely returning to Earth.
SM