Only certain animals can recognize themselves in a mirror: Humans, apes, dolphins, orcas, elephants, and European magpies.
In the 1950s, Canada used a “fruit machine” test to identify and eliminate homosexuals from public service.
The rabbit test was an early pregnancy test developed in 1927 by Bernhard Zondek and Selmar Aschheim. The test consisted of injecting the tested woman’s urine into a female rabbit, then examining the rabbit’s ovaries a few days later, which would change in response to a hormone only secreted by pregnant women. Modern pregnancy tests use the same principle but no longer require an animal to discover the presence of the pregnancy hormone.