In The Call of the Wild curly was killed because

Answer 1

he got into a fight with another sled dog named Spitz. Curly was a friendly and inexperienced dog who did not understand the savage nature of the Yukon. When Curly playfully approached Spitz, the more aggressive and dominant dog attacked her. Despite Buck's attempt to intervene, Curly was overpowered and killed by Spitz. This incident showed Buck the harsh reality of life in the wild and the need for survival instincts.