Editing Stoat (section)

==Behaviour and ecology==
===Reproduction and development===
[[File:Mustela.erminea.young.jpg|thumb|Young stoat]]
In the Northern Hemisphere, mating occurs in the April–July period. In spring, the male's [[testes]] are enlarged, a process accompanied by an increase of [[testosterone]] concentration in the [[Blood plasma|plasma]]. [[Spermatogenesis]] occurs in December, and the males are fertile from May to August, after which the testes regress.<ref>Gulamhusein, A. P., and W. H. Tam. "[https://rep.bioscientifica.com/downloadpdf/journals/rep/41/2/jrf_41_2_006.pdf Reproduction in the male stoat, Mustela erminea] {{Webarchive|url=https://web.archive.org/web/20220806231104/https://rep.bioscientifica.com/downloadpdf/journals/rep/41/2/jrf_41_2_006.pdf |date=2022-08-06 }}." Reproduction 41.2 (1974): 303–312.</ref> Female stoats are usually only [[Estrous cycle|in heat]] for a brief period, which is triggered by changes in day length.<ref name="k215">{{Harvnb|King|Powell|2007|pp=215}}</ref> [[Copulation (zoology)|Copulation]] can last as long as 1 hour.<ref>Amstislavsky, Sergei, and Yulia Ternovskaya. "[https://web.archive.org/web/20171117174933/https://pdfs.semanticscholar.org/f3b8/69a6701e7bb11035119faf36745f0bd0fafc.pdf Reproduction in mustelids]." Animal Reproduction Science 60 (2000): 571–581.</ref> Stoats are not [[Monogamy in animals|monogamous]], with litters often being of mixed paternity. Stoats undergo [[embryonic diapause]], meaning that the embryo does not immediately implant in the uterus after fertilization, but rather lies dormant for a period of nine to ten months.<ref name="k209">{{Harvnb|King|Powell|2007|pp=209–210}}</ref> The [[gestation period]] is therefore variable but typically around 300 days, and after mating in the summer, the offspring will not be born until the following spring – adult female stoats spend almost all their lives either pregnant or in heat.<ref name="k215"/> Females can reabsorb embryos and in the event of a severe winter they may reabsorb their entire litter.<ref name="k255">{{Harvnb|King|Powell|2007|pp=255}}</ref> Males play no part in rearing the young, which are born blind, deaf, toothless and covered in fine white or pinkish down. The [[milk teeth]] erupt after three weeks, and solid food is eaten after four weeks. The eyes open after five to six weeks, with the black tail-tip appearing a week later. [[Lactation]] ends after 12 weeks. Prior to the age of five to seven weeks, kits have poor [[thermoregulation]], so they huddle for warmth when the mother is absent. Males become sexually mature at 10–11 months, while females are sexually mature at the age of 2–3 weeks whilst still blind, deaf and hairless, and are usually mated with adult males before being [[weaning|weaned]].<ref name="h464">{{Harvnb|Harris|Yalden|2008|pp=464–465}}</ref>

===Territorial and sheltering behaviour===
[[File:StoatDen3 (cropped).jpg|thumb|Stoat nesting in a hollow tree.]]
Stoat territoriality has a generally mustelid spacing pattern, with male territories encompassing smaller female territories, which they defend from other males. The size of the territory and the ranging behaviour of its occupants varies seasonally, depending on the abundance of food and mates. During the breeding season, the ranges of females remain unchanged, while males either become roamers, strayers or transients. Dominant older males have territories 50 times larger than those of younger, socially inferior males. Both sexes [[territorial marking|mark their territories]] with [[urine]], [[feces]] and two types of [[scent mark]]s; anal drags are meant to convey territorial occupancy, and body rubbing is associated with agonistic encounters.<ref name="h460">{{Harvnb|Harris|Yalden|2008|pp=460–461}}</ref>

The stoat does not dig its own burrows, instead using the burrows and nest chambers of the rodents it kills. The skins and underfur of rodent prey are used to line the nest chamber. The nest chamber is sometimes located in seemingly unsuitable places, such as among logs piled against the walls of houses. The stoat also inhabits old and rotting stumps, under tree roots, in heaps of brushwood, haystacks, in bog hummocks, in the cracks of vacant mud buildings, in rock piles, rock clefts, and even in [[magpie]] nests. Males and females typically live apart, but close to each other.<ref name="s1021">{{Harvnb|Heptner|Sludskii|2002|pp=1021–1022}}</ref> Each stoat has several dens dispersed within its range. A single den has several galleries, mainly within {{cvt|30|cm}} of the surface.<ref name="h461">{{Harvnb|Harris|Yalden|2008|p=461}}</ref>

===Diet===
As with the [[least weasel]], mouse-like rodents predominate in the stoat's diet. It regularly preys on larger rodent and [[lagomorph]] species, and takes individuals far larger than itself. In Russia, its prey includes rodents and lagomorphs such as [[European water vole]]s, [[common hamster]]s, [[pika]]s and others, which it overpowers in their burrows. Prey species of secondary importance include small [[bird]]s, [[fish]], and [[shrew]]s and, more rarely, [[amphibian]]s, [[lizard]]s, and [[insect]]s.<ref name="s1018">{{Harvnb|Heptner|Sludskii|2002|p=1018}}</ref> It also preys on [[lemming]]s.<ref>{{cite news |title=It's Feast Or Famine: Predators May Drive Lemming Cycles, Science Researchers Say |date=2003 |author=American Association For The Advancement Of Science |publisher=ScienceDaily |url=https://www.sciencedaily.com/releases/2003/11/031104063521.htm#:~:text=The%20results%20showed%20the%20stoats,exclusively%20on%20lemmings%20for%20prey |access-date=2023-11-28 |archive-date=2016-09-05 |archive-url=https://web.archive.org/web/20160905111350/https://www.sciencedaily.com/releases/2003/11/031104063521.htm#:~:text=The%20results%20showed%20the%20stoats,exclusively%20on%20lemmings%20for%20prey |url-status=live }}</ref>
In Great Britain, [[European rabbit]]s are an important food source, with the frequency in which stoats prey on them having increased between the 1960s and mid 1990s since the end of the [[myxomatosis]] epidemic. Typically, male stoats prey on rabbits more frequently than females do, which depend to a greater extent on smaller rodent species. British stoats rarely kill shrews, [[rat]]s, [[squirrel]]s and water voles, though rats may be an important food source locally. In Ireland, shrews and rats are frequently eaten. In mainland Europe, water voles make up a large portion of the stoat's diet. [[Hare]]s are sometimes taken, but are usually young specimens.<ref name="h463"/> In New Zealand, the stoat feeds principally on birds, including the rare [[Kiwi (bird)|kiwi]], [[New Zealand kaka|kaka]], [[Yellowhead (bird)|mohua]], [[yellow-crowned parakeet]], and [[New Zealand dotterel]].<ref name="h463">{{Harvnb|Harris|Yalden|2008|p=463}}</ref> Cases are known of stoats preying on young [[muskrat]]s. The stoat typically eats about {{cvt|50|g}} of food a day, which is equivalent to 25% of the animal's live weight.<ref name="s1020">{{Harvnb|Heptner|Sludskii|2002|p=1020}}</ref>

[[File:Stoat killing a rabbit.jpg|thumb|Stoat killing a [[European rabbit]]]]
The stoat is an opportunistic predator that moves rapidly and checks every available burrow or crevice for food. Because of their larger size, male stoats are less successful than females in pursuing rodents far into tunnels. Stoats regularly climb trees to gain access to birds' nests, and are common raiders of nest boxes, particularly those of large species. The stoat reputedly mesmerises prey such as rabbits by a "dance" (sometimes called the [[weasel war dance]]), though this behaviour could be linked to ''[[Metastrongylidae|Skrjabingylus]]'' infections.<ref name="h463"/> The stoat seeks to immobilize large prey such as rabbits with a bite to the spine at the back of the neck. The stoat may [[surplus killing|surplus kill]] when the opportunity arises, though excess prey is usually [[Cache (biology)|cached]] and eaten later to avoid [[obesity]], as overweight stoats tend to be at a disadvantage when pursuing prey into their burrows.<ref name="v417">{{Harvnb|Verts|Carraway|1998|p=417}}</ref> Small prey typically die instantly from a bite to the back of the neck, while larger prey, such as rabbits, typically die of [[Shock (circulatory)|shock]], as the stoat's canine teeth are too short to reach the spinal column or major arteries.<ref name="h463"/>

===Communication===
The stoat is a usually silent animal, but can produce a range of sounds similar to those of the least weasel. Kits produce a fine chirping noise. Adults trill excitedly before mating, and indicate submission through quiet trilling, whining and squealing. When nervous, the stoat hisses, and will intersperse this with sharp barks or shrieks and prolonged screeching when aggressive.<ref name="h460"/>

Aggressive behavior in stoats is categorized in these forms:<ref name="h460"/>
* Noncontact approach, which is sometimes accompanied by a threat display and vocalization from the approached animal
* Forward thrust, accompanied by a sharp shriek, which is usually done by stoats defending a nest or retreat site
* Nest occupation, when a stoat appropriates the nesting site of a weaker individual
* [[Kleptoparasitism]], in which a dominant stoat appropriates the killing of a weaker one, usually after a fight.

Submissive stoats express their status by avoiding higher-ranking animals, fleeing from them or making whining or squealing sounds.<ref name="h460"/>

===Predators===
Larger mammalian predators such as [[red fox]]es (''Vulpes vulpes'') and [[sable]]s (''Martes zibellina'') are known to prey on stoats.<ref name="s1025">{{Harvnb|Heptner|Sludskii|2002|p=1025}}</ref> Additionally, a wide range of [[birds of prey]] can take stoats, from small [[northern hawk-owl]]s (''Surnia ulula'') and [[short-eared owl]]s (''Asio flammeus'') to various [[Buteo|buzzards]], [[milvus|kites]], [[goshawk]]s, and  even [[Eurasian eagle-owl]]s (''Bubo bubo'') and [[golden eagle]]s (''Aquila chrysaetos'').<ref>Korpimäki, Erkki, and Kai Norrdahl. "Avian predation on mustelids in Europe 1: occurrence and effects on body size variation and life traits." Oikos (1989): 205–215.</ref> Although not classified as birds of prey, [[grey heron]]s (''Ardea cinerea'') are known to prey on stoats.<ref>SAWARA, Yuji, Muneki SAKUYAMA, and Gen DEMACHI. "Diets and foraging site utilization of the Grey Heron, Ardea cinerea, in the breeding season." Japanese Journal of Ornithology 43.2 (1994): 61–71.</ref>

===Diseases and parasites===
[[Tuberculosis]] has been recorded in stoats inhabiting the former Soviet Union and New Zealand. They are largely resistant to [[tularemia]], but are reputed to suffer from [[canine distemper]] in captivity. Symptoms of [[mange]] have also been recorded.<ref name="h466">{{Harvnb|Harris|Yalden|2008|p=466}}</ref>

Stoats are vulnerable to [[ectoparasite]]s associated with their prey and the nests of other animals on which they do not prey. The [[louse]] ''Trichodectes erminea'' is recorded in stoats living in Canada, Ireland and New Zealand. In continental Europe, 26 [[flea]] species are recorded to infest stoats, including ''Rhadinospylla pentacantha'', ''Megabothris rectangulatus'', ''Orchopeas howardi'', ''Spilopsyllus ciniculus'', ''Ctenophthalamus nobilis'', ''[[Moorhen flea|Dasypsyllus gallinulae]]'', ''[[Northern rat flea|Nosopsyllus fasciatus]]'', ''Leptospylla segnis'', ''Ceratophyllus gallinae'', ''Parapsyllus n. nestoris'', ''Amphipsylla kuznetzovi'' and ''Ctenopsyllus bidentatus''. [[Tick]] species known to infest stoats are ''Ixodes canisuga'', ''[[Ixodes hexagonus|I. hexagonus]]'', and ''[[Ixodes ricinus|I. ricinus]]'' and ''[[Haemaphysalis longicornis]]''. Louse species known to infest stoats include ''Mysidea picae'' and ''[[Polyplax spinulosa]]''. [[Mite]] species known to infest stoats include ''[[Neotrombicula|Neotrombicula autumnalis]]'', ''[[Demodex|Demodex erminae]]'', ''[[Eulaelaps|Eulaelaps stabulans]]'', ''Gymnolaelaps annectans'', ''Hypoaspis nidicorva'', and ''[[Listrophorus|Listrophorus mustelae]]''.<ref name="h466"/>

The [[nematode]] ''[[Skrjabingylus nasicola]]'' is particularly threatening to stoats, as it erodes the bones of the [[nasal sinus]]es and decreases fertility. Other nematode species known to infect stoats include ''[[Capillaria (nematode)|Capillaria putorii]]'', ''Molineus patens'' and ''Strongyloides martes''. [[Cestode]] species known to infect stoats include ''[[Taenia (flatworm)|Taenia tenuicollis]]'', ''Mesocestoides lineatus'' and rarely ''[[Acanthocephala]]''.<ref name="h466"/>