The first sent into outer space were... fruit flies, which flew to a height of about 100 kilometers inside a Nazi rocket, the V2 in 1947. This V2 rocket housed a group of vinegar flies or fruit flies that we doubt very much that they had proper names like the case of Laika. It was launched into space and so were some seeds. The objective was to know the effects of this type of travel, of height, acceleration, and especially radiation... on these insects because they respond to many of the substances that include drugs for humans and, thanks to their speed of reproduction it is easy to see how the different generations respond to the experiments carried out. 

In the years that followed, NASA sent several monkeys, named Alberto I, II, III, IV, into space, along with monitoring instruments. They all died.

It was not until the flight of a monkey named Yorick (accompanied by 11 mice) in September 1951 that scientists were able to claim that they had sent a primate into space and returned it to Earth alive.