It is hard not to be cynical: The only purpose of casting Suri Cruise, with her famous parentage, would be to increase box-office receipts.  It would have nothing to do with art, or with ethics.

Certain extremist ideological animal-rights types, playing God, had decreed that Knut could not expect the life of a normal polar bear, raised by its mother in the wild, and therefore should be euthanized.  Fortunately, kinder souls intervened.

Similarly, in casting the voice-actor to speak for Knut, let us not acquiesce to the insensitive powers-that-be, but let us respect Knut for who he is.

Anyway, you would think people would notice that the voices of young girls and those of young boys are hardly interchangeable.  Choir directors will tell you that.  The voices of adult women can produce the most glorious sounds we may ever hope to hear (to consider e.g. Maria Callas and Patti LuPone).  But the voices of pre-pubescent girls are thin and shrill, compared to the voices of pre-pubescent boys.

Nancy Cartwright is quite exceptional in this regard.  She has famously and gloriously done the voice of one of the greatest boy-characters in the history of drama, Bart Simpson.  But she is a professional "voice-actress."  She is the exception that proves the rule.  Plus, having been born in 1951, she has had a bit of a head start on Suri.

Arguably the most emasculating bit of theater ever done, at least in the twentieth century, is the 1960 production, often televised in the 60s, of "Peter Pan," with the Broadway musical actress Mary Martin in the title role.  Martin had already achieved fame playing virtuous young women in "South Pacific" and "The Sound of Music."  But the role of Peter Pan is one of the most dashing and lusty of all male characters, albeit he is stuck on the eve of puberty.  Whatever were the producers thinking?

That production is far from a waste, though.  The great Australian character actor Cyril Ritchard does Captain Hook: surely one of the most delicious villains of all time.

Chickens deserve our true friendship! So do fish! So do other sentient beings! Let us learn to be kind.

http://www.goldencompassmovie.com/wwf/

"TGC" takes place in a parallel world like our own in some regards, but quite different in others.  Two animal-related differences:

First, some animals speak.  One of these is Iorek Byrnisson, a polar bear of Svalbard, who is a heroic character, and becomes a friend of the heroine, the young teen-age girl Lyra.

Secondly, one of the most ingenious literary creations I have ever come upon: every human being has a "daemon," an animal-companion who is on the one hand a separate character, but on the other a vessel for some essential part of the human being's personality or soul.  Lyra's daemon is a marmoset; her father's is a snow leopard; the evil and guileful Mrs. Coulter's is a golden monkey.  Members of the servant class all have dogs.  Witches have birds (I forget what kinds: corvids?, raptors?, gulls?).

The wider diffusion, beyond just those who have read the trilogy, of the idea that human beings can discover a certain wordless psychological kinship with animals, is exciting to some of us who promote animal rights.

Chickens deserve our true friendship! So do fish! So do other sentient beings! Let us learn to be kind.