A Case Report of Feeding on an Egg Mass of the Japanese Treefrog (Rhacophorus arboreus) by a Wild Japanese Macaque (Macaca fuscata)

Abstract

We observed a male Japanese macaque (Macaca fuscata) feeding on a foam nest of the Japanese tree frog (Rhacophorus arboreus). On 1st July 2013, an adult male (perhaps a solitary individual) fed on an egg mass twice at approximately 17:00 at Juni-ko lakes (Nagaike Pond), Shirakami Mountains. The monkey tore the egg mass apart by hand and ingested it without removing the foam, which is diferent from the more typical response to feeding on sticky items, such as snails and gum. This is the irst case report of feeding on the egg mass of tree frogs by Japanese macaques.