It seems like Curly represents the brutality of violence that dogs face in the frozen North. Her most memorable moment in the limelight is when she gets totally mauled by a husky she tried to befriend:
There was no warning, only a leap in like a flash, a metallic clip of teeth, a leap out equally swift, and Curly's face was ripped open from eye to jaw. (2.2)
...and her most memorable moment after that is when she gets torn to pieces. Poor doggy.
Curly reminds us that life in the wild is extremely difficult. To make a long story short, you do not want to play Curly in your school’s production of The Call of the Wild...unless you're really good at stage-fighting and screaming your head off.