The back of the body and tail of the blue-bellied squirrel are olive brown, the ventral surface of the body is gray, blue-gray, light red, red-gray and light yellow; the body is gray-brown on the side, and some have a white spot on the buttocks. The upper part of the tail is similar to the back of the body, the lower part is slightly lighter than the upper part, and the tail is usually black.

I. Morphological characteristics

The Irrawaddy squirrel is 160-185 mm long. The tail is usually longer than the body, but narrower, about 162-192 mm long; the ears are 17-20 mm long; the hind feet are 41-47.5 mm long. Cranial length is generally 44-48 mm, individual subspecies is up to 51 mm, zygomatic width is 28-32.5 mm, palate length is 21.5-24.8 mm, nasal bone length is 13.4-13.9 mm, orbital width is 15.1-15.8 mm, and auditory bubble length is 10.7-12.4 mm mm, the upper buccal dentition is 9.3 to 10.7 mm long. The skull is basically the same as that of the red-bellied squirrel, only slightly smaller.

The back of the body and tail of the blue-bellied squirrel are olive brown, the ventral surface of the body is gray, blue-gray, light red, red-gray and pale yellow; the body is gray-brown on the side, and some have a white spot on the buttocks. The upper part of the tail is similar to the back of the body, the lower part is slightly lighter than the upper part, and the tail is usually black.

The skull is slightly smaller than that of the red-bellied squirrel, the nasal bone and palate are shorter, and the orbital space is slightly narrower than that of the red-bellied squirrel. The rear end of the nasal bone is slightly beyond the rear end of the premaxilla, and its length is shorter than the interorbital width; the posterior border of the frontal bone is straight, the incisor foramen is very short, and the middle of the posterior border of the palatine bone is slightly prominent. The posterior border of the third upper molar extends posteriorly beyond the level of the posterior border of the palatine bone.

2. Habits and reproduction

A medium-sized arboreal squirrel of the Vietnamese subspecies blue-bellied squirrel, with a body length of 175-230 mm, a tail length of 180-260 mm, and no hair tufts on the ears. The body is olive gray on the back, blue-gray on the ventral surface, and has no stripes in the center of the abdomen. Central-southern squirrel is an endemic species in northern Indochina. Its distribution area is narrow. In my country, it is only found in Hekou, Jinping, Pingbian (Dawei Mountain), Honghe, Mengzi, Gejiu (Manju) and Jian in the southern part of Honghe River in Yunnan. Shui, Lvchun, Jiangcheng, Puwen, Xiaomengyang, Menglun and Mengla; it is distributed abroad in northwestern Vietnam (west of the Red River) and northern Laos (east of the Mekong River, north of Vientiane), with a distribution range of less than 100,000 km2 .

It is a species of arboreal squirrel in the tropical region of northern Indochina. It mainly inhabits tropical rain forests, monsoon forests, subtropical monsoon evergreen broad-leaved forests and sparse shrubs, mostly in forest margins with many vines It is also occasionally seen on the sparse trees or fences around the village. The altitude of habitat is generally not more than 1000m. Nests are mostly in tree cavities or under dry tree roots. Active during the day, more frequent in the early morning and before dusk. It mainly eats berries and seeds, especially the fruit of banyan tree, Niteng, wild banana, mountain lychee, longan, loquat, banana, etc. It also eats some sap young leaves, flower buds, bird eggs and insects. Solitary or paired (breeding mating season). The mating season is from March to April every year, the gestation period is about one month, and the litter is born in April to May. One litter per year, each litter of 2 to 4 cubs, with 2 to 3 cubs in the majority.

Blue-bellied Squirrel Indo-Burmese subspecies (Callosciurus pygerythrus stevensi) Thomas named in 1908 also known as blue-bellied squirrel Yunnan subspecies and Yunnan-bellied squirrel. Body ventral gray to bluish gray. The body length is 176-185mm, the tail is longer than the body, about 188-192mm long, and the tail hair is about 26-31mm wide. Distributed in southern Yunnan and southeastern Tibet, Medog and other places. Abroad in Burma and Assam, India.