JAKARTA, Indonesia — A disoriented, pregnant orangutan, her treetop home in Indonesian Borneo reduced to charred wood, is rushed to a rehabilitation center by conservationists, who dodged walls of fire and toxic smoke.

Veterinarians care for 16 abandoned baby orangutans already living at the center. The babies had developed respiratory infections because of haze from the fire, delaying the conservationists’ continuing attempts to teach them how to live on their own in the wild.

Long-awaited heavy rains this week in the Indonesian regions of Sumatra and Kalimantan appeared to be the beginning of the end of the mass forest fires that have raged since late August, Indonesia’s worst such disaster in at least 20 years.

While plenty has been written about the economic costs of the fires and the human suffering they have caused — hundreds of thousands of people sickened by the haze in Indonesia and Southeast Asia, and a regional price tag that one expert estimated at more than $14 billion — so far, scientists and environmentalists can only speculate about the extent of the damage to wildlife, including endangered species like the orangutan.