Japanese squirrel

Article

January 18, 2022

Japanese squirrel (Japanese squirrel Sciurus lis) is a rodent that belongs to the genus Squirrel of the family Squirrelidae.

Distribution

Endemic to Japan (Honshu, Shikoku, Kyushu , Awaji Island?). The habitat status of Awaji Island in recent years is unknown. It is believed to be extinct in Hiroshima Prefecture.

Form

Body length 16-22 cm. Tail length 13-17 cm. Weight 0.3 kg. The coat on the abdomen and the tip of the tail is white. The number of chromosomes is 2n 40. In the summer, the back is reddish brown (summer hair), and in the winter, the body hair at the tip of the auricle grows and the back becomes grayish brown (winter hair). In winter hair, slightly white hair grows around the eyes.

Classification

Formerly a variant of the red squirrel. It is believed that the red squirrel that invaded Japan via Sakhalin is a divergent species. Molecular phylogenetic analysis that determined the base sequence of cytochrome b in mitochondrial DNA estimates that it diverged 3,400,000 years ago, and fossils have also been found in the Middle Pleistocene strata. On the other hand, in the molecular phylogenetic analysis that determined the base sequence of 12S rRNA, there is an analysis result that the genetic difference from the red squirrel is only the individual mutation level in the genus Chipmunk and the genus Petaurista.

Ecology

It inhabits forests from flatlands to subalpine zones and prefers low mountain pine forests. Tree-dwelling. Diurnal. They live within a 10-hectare home range, and their home ranges overlap between males and between the opposite sex, but not between females. Create a spherical nest on the tree by combining tree branches and bark. Eating habit is almost herbivorous. From summer to winter, we mainly eat seeds such as onigurumi, red pine, larch, and pinus parviflora of the Pinaceae family. They also eat plant buds, flowers, fruits, seeds, mushrooms, insects, arthropods, etc., and sometimes store food by burying it between branches or in the ground (hoarding). In spring, the proportion of plants other than seeds is increased. The breeding style is embryo. From spring to summer, 2-6 cubs are laid once or twice a year. Lifespan is 5 years.

Relationship with humans

In the past, it was edible and sometimes fur was used. It used to be a hunting beast, but the number of catches has decreased since World War II. Excluded from hunting birds and beasts in 1994. Japanese squirrel in the Chugoku region There is concern that the population will decrease due to development and habitat destruction due to pine wilt disease. Since the habitat has not been confirmed on the Yamaguchi Red List since 1981, it is classified as Critically Endangered as of 2002, and as of 2004, it is judged as an extinct species because there are no cases of discovery after 1966 on the Hiroshima Red List. ing. In 2005-2007 surveys such as visual inspection and confirmation of eclipse marks in the Chugoku region, no traces of this species could be confirmed west of the Hino River in Tottori Prefecture and west of the Takahashi River in Okayama Prefecture. Reported cases were sporadic in Shimane and Yamaguchi prefectures, and no trace of this species could be confirmed in forests with an altitude of 300 meters or less. No trace of this species was confirmed in Hiroshima prefecture (on the other hand, traces were found around the prefectural border between Shimane / Yamaguchi prefecture and Hiroshima prefecture, so it may be distributed in Hiroshima prefecture as well). Endangered regional population (Ministry of the Environment Red List) Japanese squirrel in Kyushu In Kyushu, it is considered extinct or almost extinct because there have been no cases of capture since the 1970s. Hunting and fur trade records indicate that the distribution was already local in the early 20th century, while hunting records were self-applied and misidentified as Japanese flying squirrels and dormouses, and outpatients such as Kurihararisu and Cimaris, which actually have hunting cases. It is possible that the seeds were included. No specimens from Kyushu ・ Reliable habitat report for over 100 years.

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