Editing Winter white dwarf hamster

{{short description|Species of hamster kept as pets}}
{{good article}}
{{speciesbox
| image = PhodopusSungorus 1.jpg
| genus = Phodopus
| species = sungorus
| authority = ([[Peter Simon Pallas|Pallas]], 1773)
| status = LC 
| status_system = IUCN3.1
| status_ref = <ref name=iucn>{{cite iucn|author= Cassola, F. | year = 2016 | title = ''Phodopus sungorus'' |errata=2017 | page = e.T17037A115139908 | doi = 10.2305/IUCN.UK.2016-3.RLTS.T17037A22354157.en | access-date = 20 September 2021}}</ref>
| range_map = PhodopusSungorusIUCN.svg
| range_map_caption = Range of ''P. sungorus''{{leftlegend|#008000|Resident|outline=gray}} 
}}
The '''winter white dwarf hamster''' ('''''Phodopus sungorus'''''), also known as the '''Russian dwarf hamster''', '''Djungarian hamster''', '''Dzungarian hamster''', '''striped dwarf hamster''', '''Siberian hamster''', or '''Siberian dwarf hamster''', is one of three species of hamster in the [[genus]] ''[[Phodopus]]''. It is ball-shaped and typically half the size of the [[Golden hamster|Syrian hamster]], so is called a dwarf hamster along with all ''Phodopus'' species. Features of the winter white hamster include a typically thick, dark grey dorsal stripe and furry feet. As winter approaches and the days shorten, the winter white dwarf hamster's dark fur is almost entirely replaced with white fur. In captivity, this does not usually happen as animals maintained as pets are generally housed indoors and exposed to artificial light that prevents the recognition of short winter daylengths. In the wild, they originate from the [[grain|wheat fields]] of [[Kazakhstan]], the [[meadows]] of [[Mongolia]] and [[Siberia]], and the birch stands of [[Manchuria]].

Winter white dwarf hamsters are common as pets in Europe and North America, and exhibit greater variance in their coats than those found in the wild. They reproduce often—more so than [[Syrian hamster]]s, and as they have no fixed breeding season, can continue to produce some numbers of offspring all year round. Young pups act aggressively to one another, while breeding females may show similar aggression to males. The winter white is known to be one of the most tameable types of hamsters.

==Naming==
The hamster has no fully accepted common name, but '''winter white dwarf hamster''' and '''Russian dwarf hamster''' are among the most often used. Confusion arises because of their physical similarity to [[Campbell's dwarf hamster]]; consequently, the name Djungarian hamster and Russian dwarf can refer to both winter white and Campbell's dwarf hamsters. The term "winter white" derives from the fact that in the wild the hamster changes its fur colour to white for the winter months. This camouflages the hamster and reduces [[predation]] when snow is on the ground. Campbell's dwarf hamsters do not change fur colour during the winter and can only be described as being "winter white" erroneously.<ref>{{Cite web|url=http://dwarfhamsterhome.com/russian-dwarf-hamster/|title = Russian Dwarf Hamster Facts & Care - Campbell Hamsters}}</ref>

The [[binomial name]] for the hamster is ''Phodopus sungorus''. The hamster was first described by [[Peter Simon Pallas]] in 1773 as a [[mouse]].<ref>Sungorus Pallas 1773 (p. 703) . Quoted in:. Ross 1998 (p. 1, synonymy of the species)</ref> The name ''sungorus'' derives from the geographic region [[Dzungaria]].<ref>Steinlechner 1998, DJUNGARIAN HAMSTER AND/OR SIBERIAN HAMSTER:
WHO IS WHO?, European Pineal Society NEWS (p. 8).</ref> In 1778, Pallas renamed the hamster to ''Mouse songarus''.<ref>Peter Simon Pallas 1778 quadrupedum species novae e ordine glirium p. 269 Quoted in Ross 1998 (p. 1, synonymy of the species)</ref>
In 1912 [[Ned Hollister]] ordered the "Mouse songarus" to the genus ''Phodopus''.<ref>Ned Hollister 1912 New mammals from the highlands of Siberia Quoted in:. Ross 1998 (p. 1, synonymy of the species)</ref> A. I. Argiropulo, in 1933, changed the name to ''priority sungorus'' <ref>Argiropulo 1933rd Quoted in:. Ross 1998 (p. 1, synonymy of the species)</ref> and determined the hamster as a [[subspecies]] of Campbell's dwarf hamster called ''Phodopus sungorus sungorus''.<ref>Argiropulo 1933 (p. 136). Quoted in Ross 1998 (p. 6, "Remarks ").</ref> Today winter white dwarf hamsters and Campbell's dwarf hamsters are considered separate species, with the winter white officially known as ''Phodopus sungorus''.

==Physical description==
[[File:Winter white hamster agouti2.jpg|left|thumb|98x98px|Agouti colouration (natural color)]]
[[File:Winter white hamster pearl.jpg|left|thumb|95x95px|Pearl colouration]]
[[File:Winter white hamster sapphire.jpg|left|thumb|95x95px|Sapphire colouration]]
[[File:Winter white hamster pearl sapphire.jpg|left|thumb|95x95px|Pearl sapphire colouration]]
[[File:Winter white hamster merle.jpg|left|thumb|95x95px|Merle colouration]]
[[File:Winter white hamster merle sapphire.jpg|left|thumb|95x95px|Merle sapphire colouration]]
The coat of the winter white dwarf hamster is less woolly than that of [[Campbell's dwarf hamster]],<ref name="aboutpets book">The Dwarf Hamster: A Guide to Selection, Housing, Care, Nutrition, Behaviour, Health, Breeding, Species and Colours (About Pets) {{ISBN|978-1-85279-210-7}}</ref> and apart from the normal colouring, they can be coloured sapphire, sapphire pearl, or normal pearl. The head and body length of the winter white dwarf hamster is 70–90&nbsp;mm, the length of the tail is 5–15&nbsp;mm, and the hind legs are 11–15&nbsp;mm.<ref name="WA1941:R1998:GC">Winogradow und Argiropulo 1941. Zitiert in: Ross 1998 (S.&nbsp;1, „General Characters“)</ref><ref name="KS1964:R1998:GC">Krylzow und Schubin 1964. Zitiert in: Ross 1998 (S.&nbsp;1, „General Characters“).</ref> The [[body weight]] changes dramatically throughout the year. It is at its lowest during the winter.<ref name="Bartness1985">Bartness & Wade, 1985. Photoperiodic control of seasonal body weight cycles in hamsters (Abstract)</ref> In males, the body weight ranges from {{convert|19|to|45|g|oz}}, and in females, {{convert|19|to|36|g|oz}}.<ref name="KS1964:R1998:GC"/> In human care, they are slightly heavier. The average lifespan of the winter white dwarf hamster is one to three years in [[Captivity (animal)|captivity]], though they can live longer. In the wild, they are known to live as little as one year.<ref name="aboutpets book" />

In summer, the fur of the winter white hamster on the back changes from ash-grey to dark brown, or sometimes pale brown with a [[tint]].<ref name="How2care">How to Care for Your Dwarf Hamster (Your first...series) {{ISBN|1-85279-150-0}}</ref> The face changes to grey or brown, while the mouth area, the [[whisker]] area, and the ears are slightly brighter.<ref name="F1973">Figala und Mitarbeiter 1973 (Abstract). Die Angaben beziehen sich auf unter natürlichen Bedingungen gehaltene Hamster.</ref> The outer ears and the eyes have black edges. The rest of the head is dark brown or black. From the head to the tail runs a black-brown dorsal stripe.<ref name="R1992:R1998">
{{cite book
  | last = Ross
  | first = Patricia
  | author-link = Patricia Ross
  | title = On activity and behavior of three taxa of dwarf hamsters of the genus ''Phodopus'' Miller, 1910
  | series = Plant Journal of Mammalogy
  | pages = 65–76 
  | year = 1992
}}
Dissertation Quoted in Ross 1998 (p. 1, Diagnosis, General Characters "</ref> The throat, belly, tail and limbs are white.<ref name="F1973" /> The ears are grey with a pinkish tint<ref name="How2care" /> with scattered black hairs. The hairs on the underside are completely white.<ref name="L2002:158">
{{cite book
  | last = Hamann
  | first = U.
  | author-link = David Mumford
  | title = The Red Book of Varieties and Schemes
  | series = Lecture notes in mathematics 1358
  | year = 1987}} Quoted in Ross, 1998 (p. 1, "Context and Content" of the genre, "Diagnosis "</ref><ref>{{cite book
  | last = Logsdail
  | first = Chris
  | title = Hamsterlopaedia. A Complete Guide to Hamster Care
  | publisher = Ringpress Books
  | page = 174
  | year = 2005
  | isbn = 1-86054-246-8
}}</ref>
The bright coat the bottom extends to the shoulders, flanks, and hips in three arches upward. It is distinguished from the darker fur on the top of the existing black-brown hair, three curved line.<ref name="KS1964:R1998:GC" />

Apart from the typical colouration, winter white dwarf hamsters can also be coloured pearl, sapphire, sapphire pearl, and marbled. Other colorations are available, but these are strongly suspected to appear only in hybrid crossings with Campbell's dwarf hamsters. Some of these colorations are mandarin, blue, argente, yellow blue fawn, camel, brown, cream, merle, and umbrous.<ref name="aboutpets book" />

In the winter, the fur is more [[Density|dense]].<ref>{{cite book
  | last = Honey
  | first = Sandra
  | author-link = David Mumford
  | title = Dwarf hamsters. Biology. Attitude. Breeding 
  | publisher = Nature-and animal-Verlag
  | series = 2nd
  | year = 2005
  | pages = 9, 56–58
}}</ref>
They sometimes have a grey tint on their heads.<ref>Pallas 1773rd Quoted in Ross 1998 (p. 1, General Characters ").</ref>
More than 10% of the hamsters kept in the first winter develop the summer coat. In the second winter, only a few change into the winter coat and winter colour is less pronounced. The [[moulting]] in the winter fur starts in October or November and is completed in December, while the summer coat begins in January or February and is completed in March or early April.<ref name="F1973" /> The ears are grey with a pinkish tint.<ref name="aboutpets book" />
Moulting both run jobs on the head and the back of the spine to the sides, the legs and the underside.<ref>{{cite book
  | last = Zdenek
  | first = Veselovský
  | title = Contribution to knowledge of Dzungars-Hamsters, ''Phodopus sungorus'' (Pallas, 1773)
  | series = Journal of Mammalogy
  | year = 1964
  | pages = 305–311}}  Quoted in Ross 1998 (p. 1-2, " form ")</ref> The hairs grow longer in the summer, to about ten millimetres long.<ref name="How2care" />

The [[pigmentation]] of hair is controlled by the hormone [[prolactin]] and colour [[genetics]].<ref>{{cite journal
  | last =  Duncan
  | first = Marilyn
  | author-link = David Mumford
  | title =  Hormonal regulation of the annual pelage color cycle in the Djungarian hamster, ''Phodopus sungorus''. I. Role of the gonads and the pituitary
  | journal = The Journal of Experimental Zoology
 | publisher = Anthology The Journal of Experimental Zoology
  | year = 1984
  | volume = 230
 | issue = 1
 | pages = 89–95
| doi = 10.1002/jez.1402300112
 | pmid = 6726149
 }}</ref>
Day length can be less than 14 hours to initiate the change to winter coat, though it is possible they may be able to sense a directional change in photoperiod length, such as in one experiment that demonstrated a transition from 16 hours of light to 14 hours initiates a change to the winter coat.<ref>Niklowitz P., Lerchi A., Nieschlag, E. 1994. Photoperiodic responses in Djungarian Hamsters (Phodopus sungorus): Importance of Light History for Pineal and Serum Melatonin Profiles. Biology of Reproduction. 51: 714-724.</ref> The change to the winter coat can be triggered in the summer by the short day lengths. The change occurs back to the summer coat in the autumn, when the length of the days change again. At internal temperatures hamsters in captivity start later with the changes. The winter colour is less pronounced in them.<ref name="F1973" /> The eyes of the winter white hamster are black, unless it is [[albino]], in which case they are red.<ref name="How2care" />

==In the wild==
[[File:Pallas PS by Tardier grey.jpg|thumb|100px|left|[[Peter Simon Pallas]] named the hamster in 1773 as ''Mouse sungorus''.]]
In the wild, the hamster's fur changes colour in the winter. This adaptation helps them to evade predators in the snow-covered [[steppe]]s.<ref name="aboutpets book" /> The hamster digs tunnels one metre deep leading to ground burrows where they can sleep, raise their young and hide from predators.<ref name="How2care" /> The [[weasel]] is one of the hamster's main predators.<ref name="KS1964:R1998:GC" /> Most of these burrows have six entrances. In the summer, the burrows are lined with moss. To keep the burrow warm in the winter, the hamster closes all but one entrance and lines the burrows with animal fur or [[wool]] that it finds. The temperature inside the burrow is usually {{convert|16.7|°C|F}}.<ref name="aboutpets book" /> The hamsters sometimes live in the [[semidesert]]s in Central [[Asia]].<ref name="J1979:R1998:E">Boris Stepanovich Yudin, Lijana Ivanova Galkina, Antonina Fedorovna Potapkina 1979 Quoted in Ross 1998 (p. 5, "Ecology ").</ref> They also live in the dry steppes and wheat or [[alfalfa]] fields, as well as on small fields in the forests of the region around [[Minusinsk]].<ref>M. N. Meier 1967 Peculiarities of the reproduction and development of''‘‘Phodopus’’ sungorus Pallas''of different geographic populations] Volume 46 Russian Cited In: Ross 1998 (p. 5, "Ecology"). The figures refer to the area of Minusinsk.</ref> The fur on the hamster's feet protect the feet from the cold ground in the cold climates in the wild.<ref name="aboutpets book" /> The [[population density]] is highly varied.<ref name="J1979:R1998:E" /> In 1968, the first four examples of the hamster were caught in Western Siberia and brought to the [[Max Planck Institute]] in [[Germany]].<ref name="How2care" />

==Pet ownership==
Winter white hamsters are often found on the pet market in Europe, Japan, and North America.<ref name="aboutpets book" /> Care of this hamster is similar to all other species of ''Phodopus''.<ref name="siberiancare">{{cite web|url=http://siberianhamster.net/siberian-hamster.html |title=Siberian Hamster |publisher=Siberian Hamster |access-date=2011-08-08}}</ref>

==Breeding==
Winter white dwarf hamsters reproduce at a faster rate than Syrian hamsters.<ref>{{cite web|url=http://www.ask-the-vet.com/breeding-hamsters-breed-hamsters.htm|title=Breeding hamsters - how to breed hamsters|access-date=8 August 2011|archive-date=12 December 2013|archive-url=https://web.archive.org/web/20131212043437/http://www.ask-the-vet.com/breeding-hamsters-breed-hamsters.htm|url-status=dead}}</ref> Research suggests biparental care in Campbell's hamsters (''P. campbelli'') but not in winter white hamsters (''P. sungorus'').<ref>Research by Dr. Katherine Wynne-Edwards at Queen's University, Ontario, Canada</ref>  Frequent fighting can occur between the pups and as soon as they are weaned from their mother, they are separated from her.  Most of the dwarf hamsters grow to 3 to 4" long. Hamsters maintained indoors that get artificial illumination during autumn and winter are likely to breed all year round, whereas in the wild and in animals maintained in captivity but under entirely natural light-dark cycles, breeding is restricted to the long days of spring and summer.<ref name="How2care" />

During the breeding time, the hamster may become aggressive. After mating, the female may want to attack the male to protect her babies. The male usually hides in holes or caves to escape the vicious bite of the female.<ref>Sandra Honey: ''Dwarf hamsters. Biology. Attitude. Breeding''. 2nd Edition. Nature and animal-Verlag, Münster 2005, {{ISBN|3-931587-96-7}}</ref> The hamster's [[estrous]] cycle lasts four days; every four days, the female may accept the male back to breed again. This usually occurs when the darkness of the evening sets in. If male and female hamsters are not housed together from a young age, determining if the female is willing to breed with the male is difficult.<ref name="aboutpets book" />

===Hybrids===
Of the five species of hamsters kept commonly as pets, only Campbell's dwarf hamster and the winter white dwarf hamster are able to interbreed and produce live hybrid offspring. Although hybrids make suitable pets, the breeding of hybrids and [[cloning]] can cause health and reproduction problems. In addition, the widespread breeding and distribution of hybrids could threaten the existence of both pure species and subspecies of the ecosystem, resulting in only mongrels. Hybridizing causes each litter to become smaller and the young begin to form [[congenital]] problems.<ref name="aboutpets book" />

==Conservation status==
This hamster is listed as of [[Least Concern]] by the [[International Union for Conservation of Nature]] (IUCN). The population and distribution size are large, and no major or widespread threats to the species are known. Population numbers in the wild are not recorded.<ref>{{Cite journal|url=https://www.iucnredlist.org/species/17037/115139908|title=IUCN Red List of Threatened Species: Phodopus sungorus|journal=IUCN Red List of Threatened Species|date=18 August 2016}}</ref>

== References ==
{{Reflist}}

==External links==
* {{Wikispecies inline|Phodopus sungorus}}

{{Hamster}}
{{Taxonbar|from=Q214633}}

[[Category:Phodopus]]
[[Category:Rodents of Asia]]
[[Category:Mammals described in 1773]]
[[Category:Mammals of Siberia]]
[[Category:Taxa named by Peter Simon Pallas]]