Since the beginning of the space program animals have played a large role in researching the final frontier. Large mammals, like monkey and dogs, were originally sent into orbit to investigate the physiological effects of space before launching humans. Thankfully there are now much more rigid standards for animal use in space, leading to more frequent use of lower-order animals like frogs, and well, some other interesting choices ...
The very first animal in space was the fruit fly in 1942. The goal of this mission was to understand the effects of space radiation on a living organism.
In the 1970s spiders Anita and Arabella, were sent to space to test the animals' ability to spin webs in zero gravity. Pictured is the first web spun in space.
In October of 1968 French scientists launched the first cat, Félicette, into space (despite claims made by Nyan cat). She made a safe return to Earth on a parachute descent.
Russia sent a pair of tortoises to outer space in 1968, but what's cool about this duo is that they were the first animals to travel into deep space.
Man's best friend was one of the first animals in space. Pictured here is Laika, originally a stray, who was aboard the Sputnik 2 craft launched by the Soviet Union in 1957. Unfortunately, she did not survive the mission.
Mummichog minnows were aboard Skylab3 to study the effects of weightlessness on an animal's ability to orient itself.
Newts are some of the most interesting animals to go to space. In the 80s, several newts with amputated forelimbs were sent to space to study the effect of space on injury repair. Newts were chosen because they are able to regrow lost limbs. Interestingly, they regrew their limbs faster in outer space.
Mice have been sent to space since the 50s, but recently they are being launched into space to study aging processes. Mice have a very similar genetic makeup to humans and space mimics what happens when we get older--bone loss, atrophy, immune dysfunction, etc.
Many chimps have been sent to space, but picture here is the very first, named Ham. His mission was special because he was taught to operate controllers while in flight. His ability to perform in space gave credence to manned flights.
Jellyfish were aboard Spacelab Life Sciences 1 to study the development of their gravity receptors in space. These gravity receptors enable jellyfish to gather spacial information and are analogous to the inner ear of humans.