Karuizawa is home to all of the large terrestrial mammals of Honshu, including large black bears, Japanese serows, Japanese serows, Japanese deer, and wild boars, in addition to medium-sized mammals such as foxes and martens and small mammals such as moles and mice. This is evidence of the rich forests that remain where they can live and find food and shelter. In order to preserve this rich environment, we must consider coexistence with animals.
Rare animals include the Japanese serow (special natural treasure), Japanese dormouse (natural treasure, Nagano Prefecture/Ministry of the Environment quasi-threatened), okoujo (Nagano Prefecture/Ministry of the Environment quasi-threatened), and bats (mountain bats/endangered II, rabbit bats/endangered II, Nagano Prefecture quasi-threatened, etc.). Detailed surveys are needed to determine the presence of bat species.
Japanese serow (Bovidae)
- Black bear
- They are about 130 cm long and weigh 60-100 kg. They are all black with a white crescent moon-like pattern on their chest. They are about the size of a large dog, so in many cases they are actually smaller than most people imagine. Their eyes are not so good, but they have excellent sense of smell and hearing. They also have well-developed claws and are good at climbing trees.
Large bears need large forests with an abundance of wild vegetables and nuts for food. In Karuizawa, where the forests from the foot of Mt. Asama, the trees in the villa area, and the mountains of the Happu Mountains are all connected with greenery, bears have lived in the forests and villa areas near people’s homes for a long time. In recent years, the living areas of bears and humans have been overlapping, and surveys and countermeasures have been conducted to prevent human accidents and unnecessary exterminations so that bears and humans can coexist in harmony.
Bears are naturally timid and avoid people. To avoid encountering bears, first of all, ring bells, radios, etc. to avoid encounters. Be especially careful at night, when bears are often active, and on rainy days, when it is difficult for bears to distinguish between sounds and smells. Also, do not let go of the leash when walking dogs. It is very dangerous if a dog chases away a bear that is hiding.
It is also necessary to keep bears away from houses by controlling food scraps and dog food outside, and by installing electric fences in fields.
- Japanese macaque
- Japanese macaques move around Karuizawa in large groups of about 80 monkeys. Sometimes, a few male monkeys become separated from the troop. They forage for leaves, flowers, and berries during the day and roost in trees at night. They become accustomed to people when they receive food from tourists and other visitors, and they may even attack people or enter people’s homes in search of food. It is necessary to keep a distance from monkeys.
- Japanese squirrel
- Designated as a town animal. They give birth to around four young in spring, and in May, you can see one smaller hatchling working together with its parents. They also eat pine cones, acorn trees, tree buds, leaves, mushrooms, and insects. They nest in tree cavities, but they also build soccer-ball sized nests on top of trees, which become conspicuous in winter when the leaves are falling.
They are often seen running in the gardens of vacation homes, but their numbers seem to be decreasing recently.
- Japanese dormouse
- 7 cm long, brown overall with a black band from head to back. Nocturnal, omnivorous, feeds on insects, fruits and tree buds, and hibernates in tree cavities or under fallen leaves from October to April.
- Stream fish such as iwana (char), yamame (landlocked salmon), and kajika (sculpin) are present, and downstream, abura-yaya (Abura-yaya) also inhabit the area and are expanding their distribution. In Minamikaruizawa, the Hotoke loach (Ministry of the Environment/Nagano Prefecture Endangered Species II) also inhabits the area.
- Although few due to the cool climate, six species of snakes, Japanese lizards and cana snakes are often found in sunny areas.
- In addition to 7 species of frogs, Hakone salamanders and newts live in Minamikaruizawa.
- Rare insects, such as alpine butterflies and the white-fronted butterflies, also inhabit the area. Fireflies, such as genji botaru and heike botaru, have been increasing in number as a result of habitat maintenance by a local volunteer group, and can be enjoyed from late June to mid-July. Recently, a firefly viewing event titled “Firefly Festival” has been held by a local youth group in Shiozawa, making the area a new firefly spot.