One planet, Imhotep, has three environments:
highlands, like the peak of Mt Horn, for human beings;
lowlands and sea surfaces for Tigeries;
undersea, in the Seas of Yang and Yin, for vaz-Siravo.
An orphaned child without adult control finds freedom in an alien culture and an exotic environment:
"Diana...had passed her life among Tigeries and Seafolk."
-Poul Anderson,
Flandry's Legacy (New York, 2012), p. 214.
(The title is ironic because Diana Crowfeather is Dominic Flandry's illegitimate daughter.)
When Diana's mother died in an accident and the man who had been living with her wanted to put Diana in the Navy school on the neighboring planet, the girl ran away because:
"...Tigeries were hunting through hills where wind soughed in waves across forests, and surf burst under three moons upon virgin islands." (
ibid.)
The authorities could not find her, then forgot. Thus, her freedom was complete. Comparable characters are:
Tabitha Falkayn brought up by Ythrians on Avalon;
Rudyard Kipling's white orphan, Kim, evading missionaries and charitable societies in order to live as he wants in "'This great and beautiful land...'" (
Kim, London, 1944, p. 193) of India;
Modesty Blaise struggling for survival in post-World War II environments.
Modesty's freedom was not chosen and her surroundings were threatening, not exotic, but, like the others on this list, she had what it took to survive and succeed.
Another list of similar characters is those brought up, in legend or in fiction, by animals:
Romulus;
Mowgli;
Tarzan;
Zantar (a comic strip parody of Tarzan, brought up by lions).
I do not think that Poul Anderson has any character on this second list?