Answer: The author, Kipling, used third-person's perspective to narrate the story. He's telling this story as an outsider/witness instead of being a character in the story.
The following paragraph from the start of the story describes the facts stated above -
"It was seven o'clock of a very warm evening in the Seeonee hills when Father Wolf woke up from his day's rest, scratched himself, yawned, and spread out his paws one after the other to get rid of the sleepy feeling in their tips. Mother Wolf lay with her big gray nose dropped across her four tumbling, squealing cubs, and the moon shone into the mouth of the cave where they all lived."