Hirakawa, H. 1983. Reingestion and resting postures: unanticipated observations. Journal of Japanese Society for hares10: 31-34 (In Japanese).
Hirakawa, H. 1989. Feeding activity of the Japanese hare in captivity. Journal of the Japanese Society for Hares16: 71-77 (In Japanese).
Hirakawa, H. 1994. Coprophagy in the Japanese hare (Lepus brachyurus): reingestion of all the hard and soft faeces during the daytime stay in the form. Journal of Zoology, London 232: 447-456. (Pdf file - 6.9 MB)
Hirakawa, H. and Okada, A. 1995. Hard faeces reingestion and the passage and recycling of large particles in the diet of the Japanese hare Lepus brachyurus. Mammalia 59: 237-247. (Pdf file - 6.1 MB)
Hirakawa, H. 1995. The formation and passage of soft and hard feces in the hindgut of the Japanese hare Lepus brachyurus. Journal of the Mammalogical Society of Japan 20: 89-94. (Pdf file - 5.0 MB)
Hirakawa, H. 1995. Coprophagy in leporidae. Honyurui Kagaku (Mammalian Science)34: 109-122 (In Japanese with English summary). (Pdf file - 476 KB)
Hirakawa, H. 1995. Why rabbits eat their feces. Animals and Zoos 47(548): 346-351 (In Japanese).
Hirakawa, H. 1996. Hard faeces reingestion in Leporids and its ecological implications. Ph. D. Thesis (Hokkaido University No. 5084. Dec. 25, 1996). 60 pp. (18 figures and 3 tables) (In Japanese)
Hirakawa, H. 1996. Hard faeces reingestion in the mountain hare. Zeitschrift fur die Zaugetierkunde 61: 379-381.(Pdf file - 1.9 MB)
Haberl, W., K. Koyasu, H. Hirakawa and R. M. Baxter 1998. A note on "rectum-licking" in shrews (Soricidae, Insectivora). Journal of Growth36(2): 77-81.
Hirakawa, H. and W. Haberl 1998. The behaviour of licking the everted rectum in shrews (Soricidae, Insectivore). Acta Theriologica43(2): 113-120. (Pdf file - 10.4 MB)
Hirakawa, H. 2001. Coprophagy in leporids and other small mammalian herbivores. Mammal Review31: 61-80. (Pdf file - 492 kb)
Hirakawa, H. 2002. Supplement: coprophagy in leporids and other small mammalian herbivores. Mammal Review32: 150-152. (Pdf file - 64 kb)