Neben diesen satirischen Büchern hat Adams auch ein Sachbuch über die bedrohten Tierarten unseres Planeten geschrieben. Trotz des doch eher ernsten Themas dringt Adams' Humor quasi aus jeder Textzeile. Beispiel:
This isn't at all what I had expected. In 1985, by some sort of journalistic accident, I was sent to Madagascar with Mark Cawardine to look for an almost extinct sort of lemur called the aye-aye. I had never met Mark, Mark had never met me, and no one, apparently, had seen an aye-aye in years. (...)Mark Cawardine's role, essentially, was to be the one who knew what he was talking about. My role, and one for which I was entirely qualified, was to be an extremely ignorant non-zoologist to whom everything that happened would come as a complete surprise.Neben dem Aye-aye berichtet dann Douglas Adams über seinen Besuch bei den Komodo-Waranen ("the world's largest lizard"), them Kakapo (einem flugunfähigen Papagei aus Neuseeland) und dem Baji -- dem inzwischen wohl endgültig ausgestorbenen Yangtse-Delphin. 2001 gab Douglas Adams einen Vortrag/Lesung an der UCSB über dieses, sein liebstes aber am wenigsten erfolgreiches Buch, den man auch bei Youtube findet: