Editing Least weasel (section)

==Description==
[[File:Mustela nivalis 03 MWNH 768.jpg|thumb|Skull of a least weasel]]
[[File:Weasel GIF.GIF|thumb|Least weasel at the [[British Wildlife Centre]]]]
[[File:Frenataermineanivalis.png|thumb|Skulls of a [[long-tailed weasel]] (top), a [[stoat]] (bottom left) and least weasel (bottom right), as illustrated in [[Clinton Hart Merriam|Merriam]]'s ''Synopsis of the Weasels of North America'']]
The least weasel has a thin, greatly elongated and extremely flexible body with a small, yet elongated, blunt-muzzled head which is no thicker than the neck. The eyes are small in relation to their head size and are bulging and dark colored. The legs and tail are relatively short, the latter constituting less than half the body length. The feet have sharp, dark-coloured claws, and the [[sole (foot)|sole]]s are heavily haired.<ref name=s967>{{Harvnb|Heptner|Sludskii|2002|pp=967–969}}</ref> The skull, especially that of the small ''rixosa'' group, has an infantile appearance when compared with that of other members of the genus ''Mustela'' (in particular, the [[stoat]] and [[Siberian weasel|kolonok]]). This is expressed in the relatively large size of the [[cranium]] and shortened facial region.<ref name=s969>{{Harvnb|Heptner|Sludskii|2002|p=969}}</ref> The skull is, overall, similar to that of the stoat, but smaller, though the skulls of large male weasels tend to overlap in size with those of small female stoats.<ref name=h468/> There are usually four pairs of nipples but these are only visible in females.

The [[baculum]] is short,<ref>{{Cite book |last=King |first=C. M. |url=https://books.google.com/books?id=In48DwAAQBAJ&dq=baculum&pg=PA199 |title=The Natural History of Weasels and Stoats: Ecology, Behavior, and Management |date=2007 |publisher=Oxford University Press, USA |isbn=978-0-19-530056-7}}</ref> {{cvt|16|to|20|mm}}, with a thick, straight shaft. [[Fat]] is deposited along the spine, kidneys, gut mesentries and around the limbs. The least weasel has muscular anal glands under the tail, which measure {{cvt|7|by|5|mm}}, and contain sulphurous volatiles, including [[thietane]]s and dithiacyclopentanes. The smell and chemical composition of these chemicals are distinct from those of the stoat.<ref name=h468>{{Harvnb|Harris|Yalden|2008|p=468}}</ref> The least weasel moves by jumping, the distance between the tracks of the fore and hind limbs being {{cvt|18|to|35|cm}}.<ref name=s991>{{Harvnb|Heptner|Sludskii|2002|p=991}}</ref>

[[File:Weaselskeleton.jpg|thumb|Skeleton, as illustrated in [[Richard Lydekker|Lydekker]]'s ''The New Natural History'']]
Dimensions vary geographically, to an extent rarely found among other mammals. Least weasels of the ''boccamela'' group, for example, may outweigh the smaller races by almost four times. In some large subspecies, the male may be 1.5 times longer than the female. The tail lengths are also variable, constituting 13 to 30 percent of the length of the body. Average body length in males is {{cvt|130|to|260|mm}}, while females average {{cvt|114|to|204|mm}}. The tail measures {{cvt|12|to|87|mm}} in males and {{cvt|17|to|60|mm}} in females. Males weigh {{cvt|36|to|250|g}}, while females weigh {{cvt|29|to|117|g}}.<ref name=s970>{{Harvnb|Heptner|Sludskii|2002|pp=970–972}}</ref>

[[File:Mustela winter.jpg|thumb|right|The winter coat is conspicuous when there is no snow on the ground.]]
The winter fur is dense, but short and closely fitting. In northern subspecies, the fur is soft and silky, but coarse in southern forms. The summer fur is very short, sparser and rougher. The upper parts in the summer fur are dark, but vary geographically from dark-tawny or dark-chocolate to light pale tawny or sandy. The lower parts, including the [[Mandible#Other vertebrates|lower jaw]] and inner sides of the legs, are white. There is often a brown spot at the corner of the mouth. The dividing line between the dark upper and light lower parts is usually straight but sometimes forms an irregular line. The tail is brown, and sometimes the tip is a little darker but it is never black. In the northern part of its range and at high altitudes, the least weasel changes colour in the winter, the coat becoming pure white and exhibiting a few black hairs in rare circumstances.<ref name=s969/><ref name=Collins>{{cite book |title=Mammals |last=Konig |first=C. |year=1973 |publisher=Collins & Co. |isbn=978-0-00-212080-7 |page=167}}</ref>