Anatomy and Physiology
The gray mouse lemur shares many traits with other mouse lemurs, including soft fur, a long tail, long hind limbs, a dorsal stripe down the back (not always distinct), a short snout, rounded skull, prominent eyes, and large, membranous, protruding ears. It has large eyes and a tapetum lucidum to enhance its vision at night. The dorsal coat is brownish-gray with various reddish tones, the flanks are light gray to beige, and the ventral fur has discrete dull beige or whitish-beige patches along portions of the belly. On the rounded face, there is a pale white patch above the nose and between the eyes; some individuals have dark orbital markings. The furred portions of the hands and feet are off-white.
The gray mouse lemur is one of the smallest primates in the world, yet it is also the largest mouse lemur. Its total length is 25 to 28 cm (9.8 to 11 in), with a head-body length of 12 to 14 cm (4.7 to 5.5 in) and a tail length of 13 to 14.5 cm (5.1 to 5.7 in). The average weight for this species is 60 g (2.1 oz), with ranges of 58 and 67 g (2.0 and 2.4 oz) and 40 and 70 g (1.4 and 2.5 oz) reported. This is smaller than the world's smallest monkey, the pygmy marmoset, which ranges between 85 and 140 g (3.0 and 4.9 oz). Weight varies by season, with both sexes building fat reserves, up to 35% of their body weight, in the tail and hind legs prior to the dry season and periods of dormancy. The tail of the gray mouse lemur can increase fourfold in volume during the wet season when it is storing fat. Even in captivity when environmental limitations are not an issue, mouse lemurs have shown a seasonal dietary preference with a greater protein intake during what would be their more active season.
Researchers have identified differences in the tooth morphology of the first and second molars between the gray mouse lemur and the reddish-gray mouse lemur. In the reddish-gray mouse lemur, the first lower molar (m1) is squared and both the first and second upper molars (M1 and M2) have slight indentations around the middle of the posterior margin. The gray mouse lemur has a more elongated m1 and lacks the aforementioned indentation on M1 and M2. In terms of its general dentition, the gray mouse lemur shares the same dental formula as all other members of its family, Cheirogaleidae:
This species has 66 chromosomes, closely resembling the karyotype of the dwarf lemurs (genus Cheirogaleus). Except for the X chromosome, all chromosomes are acrocentric (with the short arm absent or virtually absent). Its genome size is 3.12 picograms (pg).
Read more about this topic: Gray Mouse Lemur
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