Necromys lasiurus
hairy-tailed akodont
(Also: hairy-tailed bolo mouse)

Necromys lasiurus (hairy-tailed bolo mouse) is distributed throughout central South America. Their range extends from Brazil and Paraguay to Bolivia and into the northern Argentine province of Misiones. (Redford and Eisenberg, 1992; Redford and Eisenberg, 1999)

Hairy-tailed bolo mice are usually found in grassland or savanna habitats. In Brazil, they can be found in the Cerrado, the regional name giveg to the Brazilian savannas or the Caatinga in the northeastern part of Brazil. They may sometimes be found in forests, typically inhabiting the area near the edges. Occasionally hairy-tailed bolo mice are known to reside in cultivated or abandoned fields. (Cangussu, et al., 2002; Henriques and Alho, 1991; Redford and Eisenberg, 1992; Redford and Eisenberg, 1999)

Hairy-tailed bolo mice are an olive-gray color with a lighter grayish white color on their belly, although the fur color does vary slightly according to geographic range. Aside from the lighter belly, they are uniformly colored. They have short ears, small eyes, and their hind feet are somewhat darker than their backs. They lack any distinctive facial markings. Their tail, for which they are named, is shorter than the length of their head and body and is lightly haired. On average, the head and body of the mice measures around 103 mm and the tail measures 75 mm. The average weight is 35 g. There is slight sexual dimorphism in that males sre larger than the females. (Cangussu, et al., 2002; Redford and Eisenberg, 1992; Redford and Eisenberg, 1999)

Although there have been many studies on the reproduction of this species, there is little information on the mating systems of hairy-tailed bolo mice.

Reproductive activity of hairy-tailed bolo mice increases during the rainy seasons (January to March) compared to the dry seasons (July to September). Reproductive rate probably follows rainfall because rainfall affects food availability, growth of vegetation, and the probability of fire. Although the peak in reproductive rate occurs during the rainy season, there is also high reproductive activity in the late dry season from October to November. Hairy-tailed bolo mice also produce more than one time a year and on average have 3-6 young per litter. (Cangussu, et al., 2002; Francisco, et al., 1995; Redford and Eisenberg, 1992; Redford and Eisenberg, 1999)

Little is known about the parental investment provided by hairy-tailed bolo mice but in related species of mice in the family Muridae offspring are altricial and the mother provides most of the parental care. ("Animal Diversity Web", 2004)

Although Necromys lasiurus is fairly well studied, the lifespan of this mouse is unknown.

There is not much information about the behavior of hairy-tailed bolo mice. What is known is that they are terrestrial, sometimes active during the day, and they dig and live in burrows. They build nests from grass, leaves, and other such debris. They live in burrows underground with multiple openings and tunnels. (Magnusson, et al., 1995; Redford and Eisenberg, 1992; Redford and Eisenberg, 1999)

Home ranges differ between males and females: female home ranges being approximately 35% the area of male home ranges. The average home range size for males is from 4138-21880 m^2 while for females the range is from 1317-5480 m^2. Female home ranges tend to be exclusive while males tend to overlap with females' ranges. The most likely reason for this difference as well as the difference in range sizes between sexes is that females can maximize their reproductive potential by defending their food source while males can benefit by coming into contact with as many females as possible. (Magnusson, et al., 1995)

There is little known about the communication among hairy-tailed bolo mice. There is also little information about the perception channels used by these mice but they probably rely heavily on their sense of touch and smell as opposed to vision. (Redford and Eisenberg, 1992)

Hairy-tailed bolo mice are primarily granivores, with 82% of their diet consisting of seeds. Such a large dependence on seeds can be a problem, especially when fires at the end of the dry season affect the vegetation and seed sources. This may be part of why there are such a large fluctuations in population size related to seed production. As a result of the fires, the mice show an increased dependence on invertebrates or insects during the following rainy season. (Feliciano, et al., 2002; Francisco, et al., 1995; Magnusson, et al., 1995; Redford and Eisenberg, 1992)

While there is little written about the predators of hairy-tailed bolo mice, there is no doubt that predation on these animals is strong, as in other small rodents.

Hairy-tailed bolo mice play an important role in the ecosystem as seed dispersers. They are also a food source for their predators. (Francisco, et al., 1995; Redford and Eisenberg, 1992)

Little is known about the economic importance of hairy-tailed bolo mice for humans.

Like most mice, hairy-tailed bolo mice are known to carry diseases and parasites. They may also damage some crops if they are living in cultivated fields. (Redford and Eisenberg, 1992)

At this time, hairy-tailed bolo mice are not threatened and they are under no special status on IUCN Red List and CITES. ("2003 IUCN Red List of Threatened Species", 2003; "Convention on International Trade in Endagered Species of Wild Fauna and Flora", 2004)

Hairy-tailed bolo mice have also be known as Bolomys lasiurus, Akodon lasiurus, A. arviculoides, A. lenguarum, Necromys lasiurus, Cabreramys lasiurus, and Zygodontomys lasiurus. (Redford and Eisenberg, 1992; Redford and Eisenberg, 1999)