1. Snow monkeys' unique wintering strategy: they FISH in Kamikochi, Japan, a new study reveals

Snow monkeys' unique wintering strategy: they FISH in Kamikochi, Japan, a new study reveals


Snow monkey in Kamikochi, Nagano, Japan.
CREDIT: Koji Tojo, Shinshu University

Nagano, Japan Snow monkeys have not previously been documented to prey on fish that live in rivers. The research group including Prof. Koji Tojo, Shinshu University Faculty of Science, reports the monkeys' fish predation and evidences the fact that aquatic insects are used as food by genomic analysis of feces. In addition, the research has identified aquatic insect species consumed by monkeys, that has not been previously achieved.

Main points:

                        • Generally speaking, monkeys reside in warmer climates on Earth while the Japanese macaques inhabit the coldest places in the world for a non-human primate. The high-altitude area of Kamikochi and Shiga Kogen in Nagano Prefecture can get as low as -20 degrees Celsius in the middle of winter.

                        • The presence of a Japanese macaque population in a habitat depends on whether or not it can survive the harshest winter season, and the population size is determined by the food resource availability during this critical time.

                        • A metagenomic analysis was conducted to comprehensively examine the DNA of 38 fecal samples of Japanese monkeys in the upper highlands (fecal samples collected to avoid duplication of fecal samples of the same individual) over the three winter seasons of 2017-2019. As a result, the DNA of freshwater fish such as brown trout and aquatic insects was detected in the fecal samples, definitively showing that survival depends on organisms living in rivers as a nutrient source in the midwinter.

Title of paper and Authors:

Title: Winter diet of Japanese macaques from Chubu Sangaku National Park, Japan incorporates freshwater biota
Journal: Scientific Reports
Published: Nov 29, 2021
DOI: 10.1038/s41598-021-01972-2

Alexander M. Milner (Shinshu University, University of Birmingham) First Author
Susanna A. Wood (Cawthron Institute)
Catherine Docherty (Shinshu University, University of Birmingham)
Laura Biessy (Cawthron Institute)
Masaki Takenaka (Tsukuba University)
Koji Tojo (Shinshu University, Faculty of Science)

EurekAlert!:Snow Monkeys Fish in the Winter (Non-human primates that reside in the coldest habitat)


Prof. Milner examining macaques' fecal samples.


From left, Dr. Takenaka (first), Prof. Tojo (third), Prof. Docherty (fourth), and Prof. Milner (fifth).