Muscardinus avellanarius, commonly known as the hazel dormouse, is a small rodent found primarily in Europe and parts of Asia. It has a round body, large eyes, and a bushy tail, typically measuring about 7 to 10 centimeters in length. This nocturnal creature prefers habitats with dense vegetation, such as woodlands and hedgerows, where it can find its main food sources: hazelnuts, fruits, and flowers. The hazel dormouse is known for its hibernation behavior, which lasts from late autumn to early spring. During this time, it enters a state of deep sleep to conserve energy. Due to habitat loss and other environmental pressures, Muscardinus avellanarius is considered a species of conservation concern in some regions.