The common degu (Octodon degus), originally native to South America, is now widely used as an experimental animal owing to several unique characteristics: common degus are highly social and use vocal sounds as communication tools. Importantly, their brain function is more complex than other laboratory rodents, making them a good model in the field of neuroscience. We established a colony of laboratory common degus and observed epilepsy-like seizures. We subsequently analyzed the process, strength, and duration of seizures by video recording. We examined 35 video images from 16 individuals (7 females and 9 males). The seizures began as abnormalities in the body parts (step 1), and then systemic tonic-clonic seizure (step 2) was observed. Following step 2, a short period of stillness (step 3) usually occurred, and then systemic tonic seizure occurred again (step 4). Ultimately, stillness (step 5) continued until recovery. We found sex-based differences in the strength and duration of seizures and observed large individual differences as well. Our results suggest that common degus have the potential to be used as a disease model for epilepsy.

A total of 67 stomach samples from raccoon dogs (Nyctereutes procyonoides) from Kochi Prefecture, southern Shikoku, were first analyzed using the point-frame method. Insects were one of the most common food sources. The proportion of fruits as food source was lower (30.4% in autumn) than that of other places. Interestingly, we found that for the raccoon dogs in Kochi Prefecture, 1) snails (Acusta despecta) accounted for 19.3% of diet in spring and were observed in diets in other seasons, and 2) crops (mainly rice) accounted for 25.0% of the total diet in spring.

Two bat carcasses were found on the Kikai-jima Island, Ryukyu Islands, Japan. The first, found on August 31, 2019, was a male with a 34.9-mm forearm and a 11.5-mm penis length. It was captured in the web of the giant wood spider Nephila pillipes, and most of its internal organs had been lost owing to feeding by spider. The second, found on September 15, 2019, was also a male with 32.2-mm forearm and 11.2-mm penis length. It was found inside a golf course office located in the southwest of the island. Based on their morphological traits, we identified these two bat carcasses as Pipistrellus abramus, and these were the first records of this species on the Kikai-jima Island. A sound survey conducted on July 21 and 23, 2019, detected an echolocation call of approximately 45 kHz throughout the island, which is within the peak frequency range of echolocation of Pipistrellus abramus.

The distributions of Mogera etigo and Mogera imaizumii were examined in two areas of the Echigo Plain, Niigata Prefecture. The first survey area was in the paddy fields of the southern region of the Kounan area, Niigata city. The second was in the paddy fields in the surroundings of central Gosen city. In the Kounan area, burrows of M. imaizumii were observed for the first time, but the distributions of M. etigo were reduced compared with those noted in the previous studies. These results suggest that M. etigo have disappeared in at least some regions of their previous range and/or have been displaced by M. imaizumii. In the eastern parts of Gosen city, the burrows of both moles were sympatrically observed. In contrast, the burrows of M. etigo found in the western regions were individually isolated. The isolated M. etigo might disappear if habitat alteration and/or competitive exclusion by M. imaizumii occurs.

The food habits of Japanese martens Martes melampus in a larch forest of the montane zone, Nagano Prefecture, Japan, were studied by fecal analysis and by determining occurrence frequency and point-frame methods. Point-frame occupancy showed that the fecal composition was dominated by mammals (64.1%) in spring and fruits in summer (65.3%) and autumn (78.0%). The fruit species, assessed by presence of seeds, changed monthly; species in summer included Cerasus spp., whereas those in autumn included Akebia spp. and Actinidia spp. One difference between this region and others was that the occupancy of insects in summer was only 4.9%, presumably because of the rich availability of fleshy fruits. Insects and leaves were overestimated by the frequency method. Occupancy-rank curves were used to suggest food supply and marten’s food preferences, which are impossible to determine using only the frequency method and point-frame method. The fruits consumed by martens included those from many forest-edge plants, which suggests the possibility of “directed dispersal” of seeds from these plants.

We found three day-roosts of Myotis yanbarensis and two day-roosts of Murina ryukyuana on the Amami-Oshima Island from 2016 to 2019. The day-roosts of Myotis yanbarensis were found inside forest culverts in a drainage hole and a crack in the ceiling. We also found two bats using a tree cavity in winter, revealing that this species uses both artificial structures and tree cavities as day-roosts. Solitary Murina ryukyuana individuals were found inside a dead leaf, 2.2 m above the ground, and inside a dead tree in the forest. Our results demonstrate that both species use tree cavities or snags, and therefore, cavity-forming trees and snags are likely important for the conservation of these bats. However, further research is needed as roost records are still sparse.

In the commemoration of Emeritus Professor Teru Aki Uchida, who was a professor at the Zoological Laboratory, Faculty of Agriculture, Kyushu University, I have described the history of the laboratory, which was established 100 years ago, and a rodent study that was started in the laboratory 73 years ago, focusing on efforts to control rodent pests. In addition, I have described the relationship between these efforts and the history of damage by rodents and countermeasures against them in Japan. After the Second World War, there was a lot of rodent damage from the 1950s to the 1980s. The laboratory has conducted applied and basic research on rodent pest control in Shikoku, Kyushu, Amami Islands, Okinawa Islands, and overseas South Sea Islands. It has evaluated the effects of rodenticides and natural enemies and issued warnings about the impacts on native species and ecosystems of introduced natural enemies, such as Mustela itatsi, which have been widely used traditionally including in that period in Japan. These were pioneering research efforts in Japan. As a future task, in order to conserve biodiversity and ecosystems, it is necessary to comprehensively implement measures against invasive species such as rodents and introduced natural enemies that have established their populations on islands, especially on those that had no predatory mammals originally.