The Neotropical pygmy squirrel (''Sciurillus pusillus'') is a South American species of

tree squirrel Tree squirrels are the members of the squirrel family (Sciuridae) commonly just referred to as "squirrels." They include more than 100 arboreal species native to all continents except Antarctica and Oceania. They do not form a single natural, o ...

, being the only living species in the genus ''Sciurillus'' and the subfamily Sciurillinae. Genetic analysis has shown it to be the sister group to all other squirrels.

Description

The Neotropical pygmy squirrel is the smallest species of tree squirrel native to the Americas, measuring on average just in head-body length, with an 11-cm tail. Adults weigh from . The fur is grizzled grey over the body, with paler, but not sharply contrasting, fur on the underparts. The head is slightly reddish, with distinct white markings behind the ears, which are shorter and more rounded than on most other tree squirrels. The limbs are slender, with the fore limbs elongated to assist in climbing. Females have six

teat A teat is the projection from the mammary glands of mammals from which milk flows or is ejected for the purpose of feeding young. In many mammals the teat projects from the udder. The number of teats varies by mammalian species and often corr ...

Distribution and habitat

Neotropical pygmy squirrels inhabit at least four widely separated regions in northern South America, in

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, Suriname, central

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, northern

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, and southern Colombia. Within these regions, they inhabit lowland tropical rainforests. Three subspecies are currently recognised, although their respective geographic distributions are unclear, and these may represent two or more distinct species. * ''S. p. pusillus'' (E. Geoffroy, 1803) * ''S. p. glaucinus'' Thomas, 1914 * ''S. p. kuhlii'' (Gray, 1867)

Biology and behaviour

Neotropical pygmy squirrels are diurnal and spend the day in the forest canopy, usually at least above the ground. They have been observed nesting in abandoned arboreal

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nests lined with fibres gathered from the machimango ('' Eschweilera'') tree. They feed by gnawing on the bark of trees, especially those of the genus ''

Parkia ''Parkia'' is a genus of flowering plants in the family Fabaceae. It belongs to the mimosoid clade of the subfamily Caesalpinioideae. Several species are known as African locust bean. In 1995, about 31 species were known.Melissa Luckow and ...

'', and probably eating either the gummy exudates produced by the trees in response to injury or the

cambium A cambium (plural cambia or cambiums), in plants, is a tissue layer that provides partially undifferentiated cells for plant growth. It is found in the area between xylem and phloem. A cambium can also be defined as a cellular plant tissue from w ...

beneath the bark. Population densities are apparently low, with normally no more than three individual per km², although groups containing more than one adult, plus young, have been observed in areas with a local concentration of food. These squirrels typically move rapidly through the trees, and are highly excitable, giving an alarm call described as similar to the sound of a

cricket Cricket is a bat-and-ball game played between two teams of eleven players on a field at the centre of which is a pitch with a wicket at each end, each comprising two bails balanced on three stumps. The batting side scores runs by str ...

. They give birth to one or two young at a time, with pregnant females having been observed in June.

Description

Distribution and habitat

Biology and behaviour

References

Further reading