It's hard to tell. She was the last dog added to the nine-dog team of Francois and Perrault, at the end of chapter two, and nothing is said about her...the reader doesn't even learn her name until early in chapter three, when she is badly injured, getting her throat slashed open in a fight between the team and a swarm of starving mangy huskies from an Indian village. A few paragraphs later comes the passage: "...Dolly, who had never been conspicuous for anything, went suddenly mad." This is the first time Dolly is directly addressed as an individual dog.
Apparently she got rabies from one of the half-wild dogs. The rest of the team flees from her in terror at her madness. She fixes on Buck and pursues him to the point of exhaustion, but Francois saves Buck by killing Dolly with an ax.
Unless you consider the ferocity -- caused by madness -- as a character trait, Dolly has no traits. As London wrote, she had never been conspicuous for anything.
the same amount of friends that michael has
Many characteristics are need, but two of the most important would be determination and common sense (if you want to call that a character trait).
main character.
Antagonist
the answer to this question is traits.
Traits
Raymond Cattell referred to the underlying traits that direct surface traits as source traits or factors. These source traits are considered the building blocks that shape an individual's personality and behavior.
round character
Gregor Mendel called the traits that disappear in the first generation recessive traits. These traits are not expressed in the offspring when there is a dominant trait present.
inheirtited traits
Genes.
a dynamic character