Why was Rikki-Tikki-Tavi lying in the hot sun?

"Rikki-Tikki-Tavi" is a short story by Rudyard Kipling. The title character is a mongoose, a creature who would have been unfamiliar to most of Kipling's readership. Kipling describes him as somewhere between a weasel and a cat.
At the beginning of the story, the narrator describes how Rikki-Tikki was washed out of his typical habitat, his burrow, by a summer flash flood, which carried him down into a roadside ditch. Unable to swim, Rikki-Tikki there found a leaf of grass to cling to; the narration suggests that he was able to prevent himself from drowning by clutching this blade of grass, but that he then lost consciousness.
When he comes back to himself, he is at this point lying in the hot sun in the middle of a garden path, where he hears a young boy saying, "Here's a dead mongoose. Let's have a funeral."
However, luckily for Rikki-Tikki, the boy's mother suggests they should take the mongoose inside in case he isn't really dead. Consequently he is taken into the family's bungalow and revived by the fire.