Hanging Egg Sacs (Hasumi)

Hanging Egg Sacs

Some hanging pairs of egg sacs above the water in the salamander Hynobius nigrescens, inhabiting Sarukura, Hokujo, Hakuba-mura, Nagano Prefecture, Japan (photographed on 21 May 2006). After a covering of snow on twigs was thawed, twigs expanded over a breeding pond were lifted up along with these attached egg sacs. This phenomenon usually occurred in this species, dwelling in a mountainous region.

At the time of examination, the pond contained 5-6 breeding males and approximately 50 pairs of egg sacs, including more than 20 pairs of egg sacs just after being deposited, 10 or more pairs of pinkish-colored egg sacs, and a pair of translucent egg sacs. Translucent or transparent egg sacs occasionally occurred in this species. Near this pond, 60-70 pairs of egg sacs (about 30 pairs were just after being deposited) and 30-40 pairs of egg sacs were deposited in each of two regions within a shallow wetland.

Accompanied Research Collaborators (alphabetical order): Masaichi Kakegawa (Tokyo Metropolitan Komatsugawa Senior High School), and Fujio Kishi and Yuko Saikawa (Shirouma Association of Naturalists).