Professor Shozaburo Watase of Tokyo Imperial University (TIU) introduced the mongoose (Urva auropunctata), an alien mammal, to the Okinawa Islands, Japan, in 1910, despite Palmer (1899) cautioning against the dangers of its introduction. It was suggested that Watase performed its introduction under the following five situations. First, Watase did not adequately refer to previous studies and generalize his findings in his Ph.D. on the morphology of the compound eyes of Arthropoda at Johns Hopkins University, indicating his minor concern with the method of science. Second, Watase introduced the mongoose without realizing the current concept of “experiment” and “hypothesis”, when Watase used the term of “experiment” in Japanese and Japanese zoologists of TIU did not understand these terms currently as well. Third, around 1910, Watase regarded artificial power as overcoming the natural world, believing in simply nature as the more his favorable side of possibilities. Fourth, Watase felt that the habu (Protobothrops flavoviridis) could be exterminated by the mongoose on the Okinawa Islands after watching a cobra (Naja sp.) being captured by a mongoose in Sri Lanka. Fifth, Watase would assume the survival of mongooses in wild conditions because a pair that was introduced to Tonaki Island killed and ate a habu and produced offspring, indicating his typological thinking of a species without considering the population.

In August 2020, a raccoon (Procyon lotor) was captured near the Bekanbeushi Marsh, a quasi-national park in eastern Hokkaido, Japan. No raccoon has ever been captured in this region before, and the impact of this black-listed invasive species’ expansion in this area is a concern. Therefore, we attempted to determine the distribution of raccoons in Bekanbeushi Marsh and surrounding areas. We installed ten camera and bait traps along the river inside the catchment area of the marsh to observe raccoons. The surveys were conducted between June and November 2021. Trace surveys, including footprint surveys, were also conducted at these points during camera maintenance. The camera traps and trace surveys resulted in several pieces of evidence for raccoon inhabitation at one observation point. We also conducted interviews and trace surveys on dairy farms close to this point. Two sightings were confirmed. Based on these results, it can be concluded that raccoons are already distributed in this area.

Abundant biological information on hair, such as stable isotopes and hormones, is available. Investigating molting phenology can enhance the reliability of such hair analyses because the timing of molting likely affects the concentrations of stable isotopes and hormones. In this study, we investigated the phenology of new hair emergence in the Pallas’s squirrel Callosciurus erythraeus by shaving the hair on the back of the animal. A total of 463 adult squirrels were captured from January 2021 to March 2022 for a control program in Yokosuka City, Kanagawa Prefecture, Japan. Pallas’s squirrels exhibit new hair emergence between April and November, although there is a slight difference in phenology between males and females. In males, significant peaks in new hair emergence were observed in May and October. However, seasonal changes in new hair emergence in females were unclear. Moreover, only females showed new hair emergence during winter. These findings suggest that Pallas’s squirrels molted over a longer period than previously thought. To better understand the molting patterns in Pallas’s squirrels, further research conducting periodic shavings of the same individual and observing hair growth is required.

Some ruminants spit out seeds that are too large to pass through the third stomach. Seed dispersal by spitting out has not been reported in sika deer (Cervus nippon), and its function as a seed disperser has been underestimated. This study examined the effects of different seed sizes on the time taken to spit out seeds by feeding Myrica rubra fruits to captive individuals. In addition, germination tests were conducted to evaluate the factors affecting the germination ratio by incubating pulp-free seeds under various environmental conditions. The results showed that 74% of the wild M. rubra seeds were spat out within 24 hours, and no seeds retaining their original shape were detected in the feces. The presence or absence of pulp did not affect the germination ratio. in vitro germination tests revealed a positive effect of temperature and a negative effect of treatment time on the germination ratio. When M. rubra seeds were soaked in rumen contents, their germination ratio was lower than that soaked in distilled water. Further field research is needed to determine the effectiveness of M. rubra seed dispersal by spitting out sika deer.