Albert Einstein's theory of relativity is actually two separate theories: his special theory of relativity , postulated in the 1905 paper, The Electrodynamics of Moving Bodies and his theory of general relativity , an expansion of the earlier theory, published as The Foundation of the General Theory of Relativity in 1916.
Timber or Grey Wolf. Once the world's most widely distributed mammal, the grey wolf has become extinct across much of its former range and its present distribution is much restricted. Grey Wolf (Canis Lupus), Carpathian Mountains, Romania.
Comstock Images/Comstock/Getty Images. Ethiopian wolves are the rarest of all canids. In fact, they are one of the rarest mammals worldwide, and are endangered. Ethiopian wolves are believed to have evolved from grey wolves that migrated from Eurasia to Northern Africa around 100,000 years ago. They are closely related to domestic dogs, coyotes and grey wolves. Their habitat lies in a remote part of Ethiopia known as the Afroalpine highlands.