Species information
Scientific name: Babina holsti
Japanese name: ホルストガエル
Chinese name: 赫氏拇棘蛙、琉球拇棘蛙
English name: Holst’s frog
Distribution: Northern Okinawajima, Tokashikijima
Ecology and description
Holst’s frog is designated as a Natural Monument of Okinawa Prefecture. With adults reaching up to 12 cm in length, it is the largest native frog species on Okinawa Island. The breeding season occurs in summer, during which males produce low-pitched calls resembling a dog’s bark to attract females. However, when encountering rivals, they emit a different, specific melodic call to declare their territory. Holst’s frog possesses a prepollex (thumb) containing a specialized bony spike, which is used for fighting other males or for more effectively grasping the female during amplexus. They lay their eggs in still water, and the eggs float on the water’s surface.
Field photographs taken during our tours, with observation dates
During the periods before and after the breeding season (April and July), large individuals are occasionally seen on the road during the 【Night Birding】 tour. At other times, smaller, sub-adult individuals that have not yet reached breeding size can be observed near streams during the 【Herping】 tour.
About Holst
The species name holsti in Babina holsti is believed to be named after the collector, though Japanese herpetological references rarely elaborate on this. “Holst” refers to P. A. Holst, a Swedish collector who traveled across East Asia under commission from British ornithologist Henry Seebohm of the British Museum.
Between 1879 and 1892, Holst collected specimens across mainland Japan, Tsushima, the Ogasawara Islands, the Iwo Islands, and the Ryukyu Islands. Based on records of Japanese Funnel-web Spider specimens, he also collected in Okinawa in 1892, during which he may have collected Holst’s frog.
From 1893 to 1895, Holst conducted fieldwork in Taiwan. According to anecdotal accounts, he was such a skilled marksman that local Indigenous people, who had initially plotted to assassinate him, were deterred. The endemic Taiwan Yellow tit (Parus holsti) was named by Seebohm based on specimens collected by Holst.
Holst died of tuberculosis in 1895 and was buried in Tainan, Taiwan. However, the cemetery was later developed by the Chinese Petroleum Corporation, and all gravestones, including Holst’s, were removed. His gravestone is now considered lost.
