Animals in space originally only served to test the survivability of spaceflight, before manned space missions were attempted. Later, animals were also flown to investigate various biological processes and the effects microgravity and space flight might have on them. To date, seven national space programs have flown animals into space: the Soviet Union, the United States, France, Argentina, China, Japan and Iran.
Can fish swim in microgravity? Do bees make honey in space? Can ant farms exist on the Space Station? These are just a few of the questions scientists hope to answer by taking animals into space.
Scientists want to know how the body reacts to microgravity. Many experiments can be conducted on humans while they work aboard the Space Shuttle or International Space Station (ISS), but many others interfere with daily activities; that’s where the animals come into play. And while scientists may not really care how a rat reacts to space conditions, animal data can transfer to human models and help prevent or solve physical issues people face today.
Animals go into space to help conduct scientific research only when absolutely necessary. Researchers prefer to research with computer models, or by involving the astronauts directly. For some experiments, however, only animals will work. Sometimes the situations need to be closely controlled-such as a monitored diet. Human astronauts generally aren’t willing to agree to eat the same amount and type of food, so this experiment would be a burden to them. Animals, however, always have monitored feedings.
Although the early animal astronauts achieved great fame, many other animals have quietly contributed to the body of scientific knowledge about life in space. As humans have grown more accustomed to space travel, fewer animals make the front-page news. Still, their contribution are important.
Some animals have been sent up as part of experiments designed by students, others by NASA and other countries. By 2004, the space shuttle program had flown over two dozen SpaceLab experimental packages. Nearly all of the experiments were designed with one main purpose in mind: to study the effects of microgravity on the biological functions of earth creatures.
Some of the biological functions that have been studied are (to name just a few): brain states, behavioral performance, cardiovascular status, fluid and electrolyte balance, metabolic state, tissue development, and mating in zero gravity.
– See more at: http://www.space.com/17764-laika-first-animals-in-space.html#sthash.m1spFK7n.dpuf