Domestic animals (both working and pets), of course, would include:

Dogs (purebreeds and mixes)

Cats

Horses

Reindeer

A variety of smaller pet animals

When I was up in Nome and the surrounding region in 2008, I saw no signs, however, of domestic cattle or other common domesticated farm animals...those were seen much farther south, in the Matanuska-Susitna Valley north of Anchorage...

(In the early 1900s, however, even possibly in the 1920s during Balto's time, there were domestic oxen and mules serving as beasts of burden along with horses and even dogsled teams.)

One can look up the native fauna of the Seward Peninsula (to the extreme southwest of which Nome actually sits) and discover what lives there. However, a short list would include:

Wolves (more inland than near the shore, and certainly out of sight of any human habitation)

Foxes (both red and arctic)

Ground Squirrels

Bears (primarily brown/grizzly bears...polar bears are almost NEVER seen that far south, and black bears which keep to inland forests)

Caribou (and semi-domesticated reindeer, which are SLIGHTLY different)

Moose

Musk Oxen

Rabbits

Arctic Hares/Snowshoe Hares/Tundra Hares

Voles

Lemmings

Shrews

Weasels and Minks

Wolverines (mostly inland and in hilly and mountainous regions)

Snowy Owls (and a variety of other North American owls)

Ptarmigan

Kittwakes

Gulls

Eagles

A variety of small song birds (finches, sparrows, etc.)

Hawks

Falcons

Snow Geese

Goshawks

Plovers

Jaegers

Swans

Cranes

Buntings

Ravens

Terns

Walrus

Seals

A variety of whales (Killer whales, Gray whales, Right whales, Humpback whales, Belugas)

A variety of salmon and trout

Eiders

A variety of ducks and loons

Curlews

Puffins

_____________________

Here are some useful links:

http://en.wikipedia.org/wiki/Beringia_upland_tundra

http://www.alaskool.org/resour [...] _reg_pro/nortsoundanimals.html

http://www.alaskool.org/resour [...] eg_pro/animals/moisttundra.htm

http://www.alaskool.org/resour [...] g_pro/animals/alpinetundra.htm

Like Mighty said, you don't need to make only animals that appeared in the movies. You can make animals that are possible for Balto's realities like coytes, birds of prey, weasels (common forest animals) or rats, cats, horses (common town animals) etc. Not sure about cattle but there were a few goat OCs.
Animals such as Dingos, lions, tropical birds and reptiles aren't suitable for Alaska in 20's.

So, animals like Canines, Horses, Cats, Rats and such are fine but other animals probably aren't due to the fact that they aren't suitable for the area/aren't found there?

You can only make characters for sources (Balto in this case) for animals that were in the movie, or animals that would have/live in Nome. Horses were used in Nome, and probably still are.