This photo of an Ainu chief, probably taken in the 1920s, comes from the Old Photos of Japan blog. The Ainu inhabited an island called Ainu Mosir before the Japanese colonized it, changed its name to Hokkaido, and "decimated" the population. The origins of the Ainu were a subject of speculation until genetic studies determined that they were “the descendants of Japan’s ancient Jomon inhabitants, mixed with Korean genes of Yayoi colonists and of the modern Japanese.”1
The New York Times reports (via Japundit )that just this year, Japan has finally recognized the rights of the indigenous Ainu. This recognition was apparently timed to coincide with Japan's hosting of an international conference of indigenous peoples on the island of Hokkaido (formerly the home of the Ainu) but it comes a little late for this rapidly disappearing culture:
In a study by the Hokkaido prefectural government in 2006, just under 24,000 people identified themselves as Ainu. Most were of mixed blood and lacked the telltale fair skin or hirsute features that distinguished older Ainu from the Japanese. But it is not known how many live outside Hokkaido since Japan has never conducted a nationwide census of Ainu.
The Ainu language, according to Wikipedia:
is often considered a language isolate, that is, a language that has not been shown to have a particularly close relation to any other language or group of languages.
It is sometimes grouped with the Paleosiberian languages, but this is merely a blanket term for several different language families that were present in Siberia prior to the advances of Turkic and Tungusic languages there. The "Paleosiberian" languages do not form a true language family, that is, a group of languages descended from a common ancestral language.
The language is classified as moribund and near to extinction. There is an oral tradition of epic poetry called yukar:
Traditional tales describe floating worlds with "Ainu Mosir", or the land of the humans (as opposed to "Kamui Mosir", the land of the gods), resting on the back of a fish whose movements cause earthquakes.
1 Diamond, Jared (June, 1998). Japanese Roots. Discover Magazine Vol. 19: 86-94.