Editing Hamster

{{short description|Subfamily of rodents (Cricetinae)}}
{{other uses}}
{{pp-semi-indef}}
{{pp-move-indef}}
{{Use dmy dates|date=October 2020}}
{{Automatic taxobox
| name = Hamster
| fossil_range = Middle [[Miocene]] – present
| image = European hamster (Cricetus cricetus) Meidling.jpg
| image_caption = ''Cricetus cricetus'', the [[European hamster]]
| taxon = Cricetinae
| authority = [[Johann Fischer von Waldheim|Fischer de Waldheim]], 1817
| subdivision_ranks = Genera
| subdivision = {{ubl
|''[[Allocricetulus]]''
|''[[Cansumys]]''
|''[[Cricetulus]]''
|''[[Cricetus]]''
|''[[Mesocricetus]]''
|''[[Nothocricetulus]]''
|''[[Phodopus]]''
|''[[Tscherskia]]''
|''[[Urocricetus]]''}}
}}

'''Hamsters''' are [[rodent]]s (order Rodentia) belonging to the [[subfamily]] '''Cricetinae''', which contains 19 [[species]] classified in seven [[genus|genera]].<ref>{{Cite web|url=https://animaldiversity.org/accounts/Cricetinae/|title=Cricetinae (Hamsters)|website=[[Animal Diversity Web]] }}</ref><ref name="Fox">{{cite book |last=Fox |first=Sue |year=2006 |title=Hamsters |publisher=T. F. H. Publications}}</ref> They have become established as popular [[small pet]]s.<ref name=Barrie/> The best-known species of hamster is the [[Golden hamster|golden or Syrian hamster]] (''Mesocricetus auratus''), which is the type most commonly kept as a pet. Other hamster species commonly kept as pets are the three species of dwarf hamster, [[Campbell's dwarf hamster]] (''Phodopus campbelli''), the [[winter white dwarf hamster]] (''Phodopus sungorus'') and the [[Roborovski hamster]] (''Phodopus roborovskii''), and the less common [[Chinese hamster]] (''Cricetulus griseus'').

Hamsters feed primarily on seeds, fruits, vegetation, and occasionally burrowing insects. In the wild, they are [[Crepuscular animal|crepuscular]]: they forage during the twilight hours. In captivity, however, they are known to live a conventionally [[Nocturnality|nocturnal]] lifestyle, waking around sundown to feed and exercise.<ref>{{cite book|first=Patricia Pope |last=Bartlett|title=The Hamster Handbook|url=https://books.google.com/books?id=QVlYZiNiSckC|date=2003|publisher=Barron's Educational Series|isbn=978-0-7641-2294-1|page=[https://books.google.com/books?id=QVlYZiNiSckC&pg=PA113 113]}}</ref> Physically, they are stout-bodied with distinguishing features that include elongated [[cheek pouch]]es extending to their shoulders, which they use to carry food back to their [[burrow]]s, as well as a short tail and fur-covered feet.

==Classification==
[[File:Hamster Ruso.jpg|thumb|right|''P. sungorus''. The [[winter white dwarf hamster]]]]
[[File:Pearl Winter White Russian Dwarf Hamster - Front.jpg|thumb|A winter white dwarf hamster]]
[[File:Roborofskiohamster.jpg|thumb|right|''P. roborovski.'' The [[Roborovski hamster]]]]
[[File:Campbells dwarf.jpg|thumb|right|''P. campbelli''. The [[Campbell's dwarf hamster]]]]
Taxonomists generally disagree about the most appropriate placement of the subfamily [[Cricetinae]] within the superfamily [[Muroidea]]. Some place it in a family [[Cricetidae]] that also includes [[vole]]s, [[lemming]]s, and [[New World rats and mice]]; others group all these into a large family called [[Muridae]]. Their evolutionary history is recorded by 15 extinct fossil genera and extends back 11.2 million to 16.4 million years to the Middle [[Miocene]] Epoch in Europe and North Africa; in Asia it extends 6 million to 11 million years. Four of the seven living genera include extinct species. One extinct hamster of ''[[Cricetus]]'', for example, lived in North Africa during the Middle Miocene, but the only extant member of that genus is the European or common hamster of Eurasia.

*Subfamily '''Cricetinae'''
**Genus ''[[Allocricetulus]]''
***Species [[Mongolian hamster|''A. curtatus'']]—Mongolian hamster
***Species [[Eversmann's hamster|''A. eversmanni'']]—Eversmann's or Kazakh hamster
**Genus ''[[Cansumys]]''
***Species [[Gansu hamster|''C. canus'']]—Gansu hamster
**Genus ''[[Cricetulus]]''
***Species [[Chinese striped hamster|''C. barabensis'']], including "''C. pseudogriseus''" and "''C. obscurus''"—Chinese striped hamster, also called Chinese hamster; striped dwarf hamster
***Species [[Chinese hamster|''C. griseus'']]—Chinese (dwarf) hamster, also called rat hamster, sometimes considered a [[synonym (biology)|synonym]] of ''C. barabensis''
***Species [[Long-tailed dwarf hamster|''C. longicaudatus'']]—long-tailed dwarf hamster
***Species [[Sokolov's dwarf hamster|''C. sokolovi'']]—Sokolov's dwarf hamster
**Genus ''[[Cricetus]]''
***Species [[European hamster|''C. cricetus'']]—European hamster, also called common hamster or black-bellied field hamster
**Genus ''[[Mesocricetus]]''—golden hamsters
***Species [[Golden hamster|''M. auratus'']]—golden or Syrian hamster
***Species [[Turkish hamster|''M. brandti'']]—Turkish hamster, also called [[Johann Friedrich von Brandt|Brandt]]'s hamster; Azerbaijani hamster
***Species [[Romanian hamster|''M. newtoni'']]—Romanian hamster
***Species [[Ciscaucasian hamster|''M. raddei'']]—Ciscaucasian hamster
**Genus ''[[Nothocricetulus]]'' - grey dwarf hamster
***Species [[Grey dwarf hamster|''N. migratorius'']]—grey dwarf hamster, Armenian hamster, migratory grey hamster; grey hamster; migratory hamster
**Genus ''[[Phodopus]]''—dwarf hamsters
***Species [[Campbell's dwarf hamster|''P. campbelli'']]—Campbell's dwarf hamster
***Species [[Roborovski dwarf hamster|''P. roborovskii'']]—Roborovski hamster
***Species [[Winter white dwarf hamster|''P. sungorus'']]—Djungarian hamster or winter-white Russian dwarf hamster
**Genus ''[[Tscherskia]]''
***Species [[Greater long-tailed hamster|''T. triton'']]—greater long-tailed hamster, also called Korean hamster
**Genus ''[[Urocricetus]]''
***Species ''[[Ladakh dwarf hamster|U. alticola]]'' - Ladakh dwarf hamster
***Species ''[[Kam dwarf hamster|U. kamensis]]'' - Kam dwarf hamster

===Relationships among hamster species===
[[File:Hamster clades.svg|thumb|right|Hamster clades]]
Neumann ''et al.'' (2006) conducted a [[molecular phylogeny|molecular phylogenetic]] analysis of 12 of the above 17 species using [[DNA sequence]] from three [[gene]]s: [[12S rRNA]], [[cytochrome b]], and [[von Willebrand factor]]. They uncovered the following relationships:<ref name=neu/>

====''Phodopus'' group====
The genus ''Phodopus'' was found to represent the earliest split among hamsters. Their analysis included both species. The results of another study<ref name=leb2003/> suggest ''Urocricetus kamensis'' and the related ''U. alticola'' belong to either this ''Phodopus'' group or hold a similar basal position.<ref name="Urocricetus">{{cite journal |last1=Lebedev |first1=V. S. |last2=Bannikova |first2=A. A. |last3=Neumann |first3=K. |last4=Ushakova |first4=M. V. |last5=Ivanova |first5=N. V. |last6=Surov |first6=A. V. |title=Molecular phylogenetics and taxonomy of dwarf hamsters ''Cricetulus'' Milne-Edwards, 1867 (Cricetidae, Rodentia): description of a new genus and reinstatement of another |journal=Zootaxa |date=26 February 2018 |volume=4387 |issue=2 |doi=10.11646/zootaxa.4387.2.5 |url=https://www.mapress.com/zt/article/view/zootaxa.4387.2.5 |access-date=9 December 2024|url-access=subscription }}</ref>

====''Mesocricetus'' group====
The genus ''Mesocricetus'' also forms a [[clade]]. Their analysis included all four species, with ''M. auratus'' and ''M. raddei'' forming one subclade and ''M. brandti'' and ''M. newtoni'' another.

====Remaining genera====
The remaining genera of hamsters formed a third major clade. Two of the three sampled species within ''Cricetulus'' represent the earliest split. This clade contains ''C. barabensis'' (and presumably the related ''C. sokolovi'') and ''C. longicaudatus''.

====Miscellaneous====
The remaining clade contains members of ''Allocricetulus'', ''Tscherskia'', ''Cricetus'', and ''C. migratorius''. ''Allocricetulus'' and ''Cricetus'' were [[sister taxa]]. ''Cricetulus migratorius'' was their next closest relative, and ''Tscherskia'' was basal.

==History==
Although the Syrian hamster or [[golden hamster]] (''Mesocricetus auratus'') was first described scientifically by [[George Robert Waterhouse]] in 1839, researchers were not able to successfully breed and domesticate hamsters until 1939.<ref name=Barrie>Barrie, Anmarie. 1995. Hamsters as a New Pet. T.F.H. Publications Inc., NJ {{ISBN|0-86622-610-9}}.</ref> The entire laboratory and pet populations of Syrian hamsters appear to be descendants of a single brother–sister pairing. These littermates were captured and imported in 1930 from Aleppo in Syria by [[Israel Aharoni]], a zoologist of the [[Hebrew University of Jerusalem|University of Jerusalem]].<ref name="Fritz">Fritzsche, Peter. 2008. Hamsters: A Complete Pet Owner's Manual. Barron's Educational Series Inc., NY {{ISBN|0-7641-3927-4}}.</ref> In Jerusalem, the hamsters bred very successfully. Years later, animals of this original breeding colony were exported to the United States, where Syrian hamsters became a common pet and laboratory animal. Comparative studies of domestic and wild Syrian hamsters have shown reduced genetic variability in the domestic strain. However, the differences in behavioral, chronobiological, morphometrical, hematological, and biochemical parameters are relatively small and fall into the expected range of interstrain variations in other laboratory animals.<ref name="Kuhnen, (2001)">Kuhnen, G. (2002). Comfortable quarters for hamsters in research institutions. In "Comfortable Quarters for Laboratory Animals" Eds V. Reinhardt and A. Reinhardt. Animal Welfare Institute, Washington DC. pp.33-37</ref>

==Etymology==
The name "hamster" is a [[loanword]] from the German, which itself derives from earlier [[Middle High German]] {{lang|gmh|hamastra}}. It is possibly related to [[Old Church Slavonic]] {{lang|cu-Latn|khomestoru}}, which is either a blend of the root of [[Russian language|Russian]] {{lang|ru|хомяк}} ({{lang|ru-Latn|khomyak}}) "hamster" and a Baltic word (cf. {{langx|lt|staras}} "hamster");<ref>{{cite dictionary |first=Douglas |last=Harper |dictionary=The Online Etymology Dictionary |url=http://www.etymonline.com/index.php?term=hamster |title=hamster}}</ref> or of Persian origin (cf. [[Avestan]]: {{lang|ae-Latn|hamaēstar}} "oppressor").<ref>{{cite dictionary |dictionary=Merriam-Webster's Collegiate Dictionary |title=hamster |access-date=29 May 2008 |url=http://www.merriam-webster.com/dictionary/hamster }}</ref> The collective noun for a group of hamsters is "horde".<ref>{{Cite book |last=Carnaby |first=Trevor |url=https://books.google.com/books?id=4u-VroUwC6QC&dq=horde+of+hamsters+%22collective+noun%22&pg=PA362 |title=Beat about the Bush: Mammals |date=2006 |publisher=Jacana Media |isbn=978-1-77009-240-2 |language=en}}</ref> In German, the verb {{lang|de|hamstern}} is derived from {{lang|de|Hamster}}. It means "[[Hoarding|to hoard]]".<ref>{{Cite dictionary |last=Geyken |first=Alexander|access-date=2009-07-01 |dictionary=Etymologisches Wörterbuch der deutschen Sprache |title=Hamster |language=de |url=http://www.dwds.de/?kompakt=1&qu=Hamster}}</ref>

==Description==
[[File:Die vergleichende Osteologie (1821) Cricetus cricetus.jpg|right|thumb|Skeleton of [[European hamster]]]]
Hamsters are typically stout-bodied, with tails shorter than body length, and have small, furry ears, short, stocky legs, and wide feet. They have thick, silky fur, which can be long or short, colored black, grey, honey, white, brown, yellow, red, or a mix, depending on the species. Two species of hamster belonging to the genus ''[[Phodopus]]'', [[Campbell's dwarf hamster]] (''P. campbelli'') and the [[Djungarian hamster]] (''P. sungorus''), and two of the genus ''[[Cricetulus]]'', the [[Chinese striped hamster]] (''C. barabensis'') and the [[Chinese hamster]] (''C. griseus'') have a dark stripe down their heads to their tails. The species of genus ''Phodopus'' are the smallest, with bodies {{convert|5.5|to|10.5|cm|in|abbr=on}} long; the largest is the [[European hamster]] (''Cricetus cricetus''), measuring up to {{convert|34|cm|in|abbr=on}} long, not including a short tail of up to {{convert|6|cm|in|abbr=on}}.

The hamster tail can be difficult to see, as it is usually not very long (about {{frac|1|6}} the length of the body), with the exception of the [[Chinese hamster]], which has a tail the same length as the body. One rodent characteristic that can be highly visible in hamsters is their sharp [[Rodent#Dentition|incisors]]; they have an upper pair and lower pair which grow continuously throughout life, so must be regularly worn down. Hamsters are very flexible, but their bones are somewhat fragile. They are extremely susceptible to rapid temperature changes and drafts, as well as extreme heat or cold.

===Senses===
Hamsters have poor eyesight; they are [[nearsighted]] and [[colorblind]].<ref>{{cite book |author=LeeAnne Engfer |others=photographs by Andy King |title=My pet hamster & gerbils|year=1997|publisher=Lerner|location=Minneapolis|isbn=978-0822522614|page=13}}</ref><ref>{{cite book|title=Concise encyclopedia biology|year=1995|publisher=Walter de Gruyter|location=Berlin|isbn=978-3110106619|page=[https://archive.org/details/conciseencyclope00scot/page/299 299]|edition=Rev.|author=Thomas A. Scott|url=https://archive.org/details/conciseencyclope00scot/page/299}}</ref> Their eyesight leads to them not having a good sense of distance or knowing where they are, but that  does not stop them from climbing in (and sometimes out of) their cages or from being adventurous. Hamsters can sense movement around at all times, which helps  protect them from harm in the wild. In a household, this sense helps them know when their owner is  near.<ref name="omlet.us">{{Cite web|url=https://www.omlet.us/guide/hamsters/about_hamsters/anatomy/|title=Anatomy {{!}} About Hamsters {{!}} Hamsters {{!}} Guide {{!}} Omlet US|website=www.omlet.us|access-date=2019-11-20}}</ref> Hamsters have [[scent glands]] on their flanks (and abdomens in Chinese and dwarf hamsters) which they rub against the surface beneath them, leaving a scent trail.<ref>{{cite book|last1=Bartlett|first1=Patricia Pope|last2=Earle-Bridges|first2=Michele|title=The Hamster Handbook|publisher=Barron's Educational Series|isbn=9780764122941|page=[https://archive.org/details/hamsterhandbook00bart/page/21 21]|url=https://archive.org/details/hamsterhandbook00bart|url-access=registration|language=en|year=2003}}</ref> Hamsters also use their sense of smell to distinguish between the sexes and to locate food. Mother hamsters can also use their sense of smell to find their own babies and identify which ones are not theirs. Their scent glands can also be used to mark their territories, their babies, or their mate.<ref name="caringpets.org">{{Cite web|url=https://www.caringpets.org/how-to-take-care-of-a-hamster/behavior-body-language/|title=Hamster Body Language & Behavior: What it Means|website=Caring Pets|language=en|access-date=2019-11-20}}</ref> Hamsters catch sounds by having their ears upright. They tend to learn similar noises and begin to know the sound of their food and even their owner's voice.<ref name="omlet.us"/> They are also particularly sensitive to high-pitched noises and can hear and communicate in the [[ultrasound|ultrasonic]] range.<ref name="Fritz"/>

===Diet===
Hamsters are [[omnivores]], which means they can eat meat and plant matter. Hamsters that live in the wild eat seeds, grass, and even insects.<ref name="omlet.us"/> Although pet hamsters can survive on a diet of exclusively commercial hamster food, other items, such as vegetables, fruits, seeds, and nuts, can be given. Although store-bought food is good for hamsters, it is best if fruits and vegetables are also in their diet because it keeps them healthier.<ref name="All About Keeping Hamsters as Pets">{{Cite web|url=https://www.thesprucepets.com/hamsters-overview-1238973|title=All About Keeping Hamsters as Pets|website=The Spruce Pets|language=en|access-date=2019-11-20}}</ref> Hamsters in the Middle East have been known to hunt in packs to find insects for food.<ref name="Encyclopædia Britannica">"hamster." [[Encyclopædia Britannica]]. Standard Edition. Chicago: Encyclopædia Britannica, 2007.</ref> Hamsters are [[Hindgut fermentation|hindgut fermenters]] and often eat their own feces ([[coprophagy]]) to recover nutrients digested in the hind-gut, but not absorbed.<ref name="Fox"/>

==Behavior==
[[File:Cream-colored long-hair pet Syrian hamster with banana.jpg|thumb|right|Pet Syrian hamster examines a banana]]

===Feeding===
A behavioral characteristic of hamsters is [[Hoarding (animal behavior)|food hoarding]]. They carry food in their spacious cheek pouches to their underground storage chambers. When full, the cheeks can make their heads double, or even triple in size.<ref name="Fox"/> Hamsters lose weight during the autumn months in anticipation of winter. This occurs even when hamsters are kept as pets and is related to an increase in exercise.<ref>{{cite journal |doi=10.1371/journal.pone.0090253 |pmid=24603871 |pmc=3946023 |title=Effect of Exercise on Photoperiod-Regulated Hypothalamic Gene Expression and Peripheral Hormones in the Seasonal Dwarf Hamster Phodopus sungorus |journal=PLOS ONE|volume=9 |issue=3 |pages=e90253 |year=2014 |last1=Petri |first1=Ines |last2=Dumbell |first2=Rebecca |last3=Scherbarth |first3=Frank |last4=Steinlechner |first4=Stephan |last5=Barrett |first5=Perry |bibcode=2014PLoSO...990253P |doi-access=free  | issn = 1932-6203}}</ref>

===Social behavior===
[[File:Hamster fight.jpg|thumb|right|Hamsters fighting]]
Most hamsters are strictly solitary. If housed together, acute and chronic [[stress (psychological)|stress]] might occur,<ref name="Kuhnen, (2001)"/> and they might fight fiercely, sometimes fatally. [[Phodopus|Dwarf hamster]] species might tolerate [[siblings]] or same-gender unrelated hamsters if introduced at an early enough age, but this cannot be guaranteed. Hamsters communicate through body language to one another and even to their owner. They communicate by sending a specific scent using their scent glands and also show body language to express how they are feeling.<ref name="caringpets.org"/>

===Chronobiology===
Hamsters can be described as [[nocturnal]] or [[crepuscular]] (active mostly at dawn and dusk). Khunen writes, "Hamsters are nocturnal rodents who are active during the night",<ref name="Kuhnen, (2001)"/> but others have written that because hamsters live underground during most of the day, only leaving their burrows for about an hour before sundown and then returning when it gets dark, their behavior is primarily crepuscular. Fritzsche indicated although some species have been observed to show more nocturnal activity than others, they are all primarily crepuscular.<ref name="Fritz"/>

In the wild Syrian hamsters can [[hibernate]] and allow their body temperature to fall close to ambient temperature. This kind of [[thermoregulation]] diminishes the [[metabolic rate]] to about 5% and helps the animal to considerably reduce the need for food during the winter.<ref name="Kuhnen, (2001)"/> Hibernation can last up to one week but more commonly last 2–3 days.<ref name="britishhamsterassociation.org.uk">{{Cite web|url=http://www.britishhamsterassociation.org.uk/get_article.php?fname=journal/hibernation.html|title=Welcome to the British Hamster Association Web Site}}</ref> When kept as house pets the Syrian hamster does not hibernate.<ref name="britishhamsterassociation.org.uk"/>

===Burrowing behavior===
All hamsters are excellent diggers, constructing burrows with one or more entrances, with galleries connected to chambers for nesting, food storage, and other activities.<ref name="Fox"/> They use their fore- and hindlegs, as well as their snouts and teeth, for digging. In the wild, the burrow buffers extreme ambient temperatures, offers relatively stable climatic conditions, and protects against predators. Syrian hamsters dig their burrows generally at a depth of {{convert|70|cm|ft|abbr=on}}.<ref name="Gattermann et al., (2001)">{{cite journal |doi=10.1017/S0952836901000851 |title=Notes on the current distribution and the ecology of wild golden hamsters (Mesocricetus auratus) |journal=Journal of Zoology |volume=254 |issue=3 |pages=359–365 |year=2001 |last1=Gattermann |first1=R. |last2=Fritzsche |first2=P. |last3=Neumann |first3=K. |last4=Al-Hussein |first4=I. |last5=Kayser |first5=A. |last6=Abiad |first6=M. |last7=Yakti |first7=R. }}</ref> A burrow includes a steep entrance pipe ({{convert|4|-|5|cm|in|abbr=on}} in diameter), a nesting and a hoarding chamber and a blind-ending branch for urination. Laboratory hamsters have not lost their ability to dig burrows; in fact, they will do this with great vigor and skill if they are provided with the appropriate substrate.<ref name="Kuhnen, (2001)"/>

Wild hamsters will also appropriate tunnels made by other mammals; the Djungarian hamster, for instance, uses paths and burrows of the [[pika]].<ref>{{Cite news|url=https://www.britannica.com/animal/hamster#ref756119|title=hamster {{!}} Facts & Breeds|last=Musser|first=Guy|work=Encyclopedia Britannica|access-date=2018-02-01|language=en}}</ref>

==Reproduction==
[[File:Hamster with babies.jpg|thumb|right|A mother Syrian hamster with pups less than one week old]]

===Fertility===
Hamsters become [[fertility|fertile]] at different ages depending on their species. Both Syrian and Russian hamsters mature quickly and can begin reproducing at a young age (4–5 weeks), whereas Chinese hamsters will usually begin reproducing at two to three months of age, and Roborovskis at three to four months of age. The female's reproductive life lasts about 18 months, but male hamsters remain fertile much longer. Females are in [[estrus]] about every four days, which is indicated by a reddening of genital areas, a musky smell, and a hissing, squeaking vocalisation she will emit if she believes a male is nearby.<ref name=Barrie/>

When seen from above, a [[sexually mature]] female hamster has a trim tail line; a male's tail line bulges on both sides. This might not be very visible in all species. Male hamsters typically have very large [[testes]] in relation to their body size. Before sexual maturity occurs, it is more difficult to determine a young hamster's sex. When examined, female hamsters have their anal and genital openings close together, whereas males have these two holes farther apart (the penis is usually withdrawn into the coat and thus appears as a hole or pink pimple).<ref name=Barrie/>

===Gestation and fecundity===
Syrian hamsters are [[seasonal breeder]]s and will produce several litters a year with several pups in each litter. The breeding season is from April to October in the Northern Hemisphere, with two to five litters of one to 13 young being born after a gestation period of 16 to 23 days.<ref name="Encyclopædia Britannica"/> Dwarf hamsters breed all through the year. Gestation lasts 16 to 18 days for Syrian hamsters, 18 to 21 days for Russian hamsters, 21 to 23 days for Chinese hamsters and 23 to 30 for Roborovski hamsters. The average litter size for Syrian hamsters is about seven pups, but can be as great as 24, which is the maximum number of pups that can be contained in the uterus. [[Campbell's dwarf hamster]]s tend to have four to eight pups in a litter, but can have up to 13. Winter white hamsters tend to have slightly smaller litters, as do Chinese and Roborovski hamsters.

===Intersexual aggression and cannibalism===
Female Chinese and Syrian hamsters are known for being aggressive toward males if kept together for too long after mating. In some cases, male hamsters can die after being attacked by a female. If breeding hamsters, separation of the pair after mating is recommended, or they will attack each other.

Female hamsters are also particularly sensitive to disturbances while giving birth, and may even eat their own young if they think they are in danger, although sometimes they are just carrying the pups in their cheek pouches.<ref name="Fritz"/> If captive female hamsters are left for extended periods (three weeks or more) with their litter, they may [[Cannibalism (zoology)|cannibalize]] the litter, so the litter must be removed by the time the young can feed and drink independently.

===Weaning===
[[File:Dwarf hamsters eating cooked, frozen beans - 03.ogv|thumb|right|250px|An adult female and several juvenile dwarf hamsters (''Phodopus sungorus'') feeding]]
Hamsters are born hairless and blind in a nest the mother will have prepared in advance.<ref name=Barrie/> After one week, they begin to explore outside the nest. Hamsters are capable of producing litters every month. Hamsters can be bred after they are three weeks old. It may be hard for the babies to not rely on their mother for nursing during this time, so it is important that they are supplied with food to make the transition from nursing to eating on their own easier. After the hamsters reach three weeks of age they are considered mature.<ref>{{Cite web|url=https://animals.mom.me/soon-can-hamster-its-mother-1312.html|title=How Soon Can You Take a Hamster From Its Mother?|website=animals.mom.me|language=en|access-date=2019-11-20}}</ref>

===Longevity===
Syrian hamsters typically live no more than two to three years in captivity, and less in the wild. Russian hamsters (Campbell's and Djungarian) live about two to four years in captivity, and Chinese hamsters {{frac|2|1|2}}–3 years. The smaller Roborovski hamster often lives to three years in captivity.<ref name="Fox"/>

==Society and culture==
===Hamsters as pets===
[[File:Hamster standing in exercise wheel.jpg|left|thumb|A [[Syrian Hamster|Syrian hamster]] (''Mesocricetus autatus)'' standing in [[Hamster wheel|exercise wheel]]]]
{{anchor|Gerbils as pets|reason=Old section name, may be linked.}}
The best-known species of hamster is the [[golden hamster|golden or Syrian hamster]] (''Mesocricetus auratus''), which is the type most commonly kept as [[pet]]s. There are numerous [[Syrian hamster variations]] including long-haired varieties and different colors. British zoologist [[Leonard Goodwin]] claimed most hamsters kept in the United Kingdom were descended from the colony he introduced for medical research purposes during the Second World War.<ref name="tel">{{cite news|url=https://www.telegraph.co.uk/news/obituaries/4241645/Leonard-Goodwin.html |archive-url=https://ghostarchive.org/archive/20220111/https://www.telegraph.co.uk/news/obituaries/4241645/Leonard-Goodwin.html |archive-date=11 January 2022 |url-access=subscription |url-status=live|title=Leonard Goodwin – Telegraph|date=14 January 2009|newspaper=The Daily Telegraph|access-date=18 January 2009}}{{cbignore}}</ref> Hamsters were domesticated and kept as pets in the United States at least as early as 1942.<ref>Testimony from Grant C Riddle (born 1929, living in Lake Wildwood, CA) who had a pet hamster in 1942.</ref>
[[File:Syrian Hamster Cage.jpg|thumb|298x298px|A spacious [[hamster cage]] made from a display cabinet]]
Other hamsters commonly kept as pets are the three species in the genus [[Phodopus]]. [[Campbell's dwarf hamster]] (''Phodopus campbelli'') is the most common—they are also sometimes called "Russian dwarfs"; however, many hamsters are from Russia, so this ambiguous name does not distinguish them from other species appropriately. The coat of the [[winter white dwarf hamster]] (''Phodopus sungorus'') turns almost white during winter (when the hours of daylight decrease).<ref name=Barrie/> The [[Roborovski hamster]] (''Phodopus roborovskii'') is extremely small and fast, making it difficult to keep as a pet.<ref name="Fox"/>

===Hamster shows===
{{main|Hamster show}}
A hamster show is an event in which people gather hamsters to judge them against each other.<ref name="Logsdail 2002 page 166-9">{{cite book|last1=Logsdail|first1=Chris|last2=Logsdail|first2=Peter|last3=Hovers|first3=Kate|title=Hamsterlopaedia : a complete guide to hamster care|date=2002|publisher=Ringpress|location=Lydney|isbn=978-1860542466|page=161}}</ref> Hamster shows are also places where people share their enthusiasm for hamsters among attendees. Hamster shows feature an exhibition of the hamsters participating in the judging.<ref name="Logsdail 2002 page 166-9"/>

The judging of hamsters usually includes a goal of promoting hamsters which conform to natural or established varieties of hamsters.<ref name="Logsdail 2002 page 166-9"/> By awarding hamsters which match standard hamster types, hamster shows encourage planned and careful hamster breeding.<ref name="Logsdail 2002 page 166-9"/>

===Owner activism===
When the first reported case of animal-to-human transmission of [[Severe acute respiratory syndrome coronavirus 2|SARS-CoV-2]] in [[Hong Kong]] took place via imported pet hamsters, researchers expressed difficulty in identifying some of the viral mutations within a global [[Genomic and medical data|genomic data]] bank, leading city authorities to announce a mass cull of all hamsters purchased after December 22, 2021, which would affect roughly 2,000 animals. After the government 'strongly encouraged' citizens to turn in their pets, approximately 3,000 people joined underground activities to promote the adoption of abandoned hamsters throughout the city and to maintain pet ownership via methods such as the forgery of pet store purchase receipts. Some activists attempted to intercept owners who were on their way to turn in pet hamsters and encourage them to choose adoption instead, which the government subsequently warned would be subject to police action.<ref>{{cite news |last1=Mahtani |first1=Shibani |last2=Yu |first2=Theodora |title=Hong Kong hamster massacre: Residents resist 'zero covid' city's pet project |url=https://www.washingtonpost.com/world/2022/01/20/hong-kong-hamsters-covid/ |access-date=22 January 2022 |newspaper=Washington Post |date=20 January 2022 |archive-url=https://web.archive.org/web/20220122005223/https://www.washingtonpost.com/world/2022/01/20/hong-kong-hamsters-covid/ |archive-date=22 January 2022}}</ref><ref>{{cite news |last1=Ting |first1=Victor |last2=Choy |first2=Gigi |last3=Cheung |first3=Elizabeth |title=Coronavirus: 2,000 hamsters to be culled over fears of first animal-to-human transmission in Hong Kong, pet store customers ordered into quarantine |url=https://www.scmp.com/news/hong-kong/article/3163775/coronavirus-hong-kong-leader-worried-about-community-outbreak |access-date=22 January 2022 |publisher=South China Morning Post |date=18 January 2022 |archive-url=https://web.archive.org/web/20220122005514/https://www.scmp.com/news/hong-kong/article/3163775/coronavirus-hong-kong-leader-worried-about-community-outbreak |archive-date=22 January 2022}}</ref>

{{anchor|Research|As research animals|As laboratory animals|As lab animals}}

===Hamsters as lab animals===
{{see|Laboratory Syrian hamster}}
The extracted cells of babies' kidneys and adults' ovaries are used to study [[cholesterol synthesis]].<ref name="Slotte-et-al-1994">{{cite book | editor-last=Hoekstra | editor-first=Dick | title=Cell lipids | publisher=[[Academic Press]] | publication-place=[[San Diego]] | year=1994 | isbn=978-0-12-153340-3 | oclc=30147917 | pages=483–502/xii+638 | issn=0070-2161 | volume=40 | chapter=19 Flow and Distribution of Cholesterol{{mdash}}Effects of Phospholipids | first1=J. Peter | last1=Slotte | first2=M. Isabella | last2=Pörn | first3=Ann-Sofi | last3=Härmälä}} {{ISBN|0-12-153340-9}} {{ISBN|9780080585116}}</ref>

==Similar animals==
Some similar rodents sometimes called "hamsters" are not currently classified in the hamster subfamily Cricetinae. These include the maned hamster, or crested hamster, which is really the [[maned rat]] (''Lophiomys imhausi''). Others are the [[mouse-like hamster]]s (''Calomyscus'' spp.), and the [[white-tailed rat]] (''Mystromys albicaudatus'').

==See also==
* [[Hamster cage]]
* [[Hamster show]]
* [[Hamster wheel]]
* [[Hamster ball]]
* [[Chinchilla]]
* ''[[Ebichu]]''
* [[Gerbil]]
* [[Guinea pig]]
* [[Hampster Dance]]
* [[Hamster racing]]
* ''[[Hamtaro]]''
* [[Rat]]
* [[Wet-tail]]

==References==
{{Reflist|35em|refs=
<ref name=leb2003>Lebedev, V. S., N. V. Ivanova, N. K. Pavlova, and A. B. Poltoraus. 2003. Molecular phylogeny of the Palearctic hamsters. ''In'' Proceedings of the International Conference Devoted to the 90th Anniversary of Prof. I. M. Gromov on Systematics, Phylogeny and Paleontology of Small Mammals (A. Averianov and N. Abramson eds.). St. Petersburg.</ref><ref name=neu>{{cite journal|pmid=16483801|title=Molecular phylogeny of the Cricetinae subfamily based on the mitochondrial cytochrome ''b'' and 12S rRNA genes and the nuclear vWF gene|year=2006|last1=Neumann|first1=K|last2=Michaux|first2=J|last3=Lebedev|first3=V|last4=Yigit|first4=N|last5=Colak|first5=E|last6=Ivanova|first6=N|last7=Poltoraus|first7=A|last8=Surov|first8=A|last9=Markov|first9=G|volume=39|issue=1|pages=135–48|doi=10.1016/j.ympev.2006.01.010|journal=Molecular Phylogenetics & Evolution|bibcode=2006MolPE..39..135N |hdl=2268/77207|url=http://orbi.ulg.ac.be/bitstream/2268/77207/1/mol%20phyl%20evol%20cricetinae.pdf}}</ref>
}}

==External links==
{{Wikispecies|Cricetinae}}
{{Wiktionary|hamster}}
{{Commons category|Cricetinae}}
{{Wikiquote}}
* [https://hamsters-uk.org/ National Hamster Council of the UK]

{{Cricetidae}}
{{Hamster}}

{{Taxonbar|from=Q6573}}
{{Authority control}}

[[Category:Cricetidae]]
[[Category:Hamsters| ]]
[[Category:Articles containing video clips]]
[[Category:Extant Miocene first appearances]]
[[Category:Taxa named by Gotthelf Fischer von Waldheim]]