Two dogs sent to space (1960) by Russians before they send Yuri Gagarin(April 12, 1961) - first man in space. Probably not many dogs (or even people) acheaved more.
(I was really tempted to call them Russian Dogs)
The really first dog in space was laika, but Belka and Strelka were the first two dogs to come back alive.
In Russian Belka (whity or squorel), Strelka (arrow).