Syrian hamster behavior

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Syrian hamster behavior refers to the ethology of the Syrian hamster (Mesocricetus auratus).

Contents

Sleeping habits

Syrian hamsters have a sleep cycle that lasts about 10 to 12 minutes. [1]

In the laboratory, Syrian hamsters are observed to be nocturnal and in their natural circadian rhythm they wake and sleep on a consistent schedule. [2] In all kinds of laboratory settings hamsters do 80% of their routine activities at night. [3] Hamsters are most active early in the night, then become less active as the night passes. [2]

A study of Syrian hamsters in the wild found that they were active almost exclusively in the daytime, which is a surprising difference from behavior in the laboratory. [2] The sleeping behavior of wild hamsters is not well understood. [2]

Reproduction

The female Syrian hamster has anatomic features that are unique from other animals. They mature between 8–10 weeks of age and have a 4-day estrous cycle. [4]

Female Syrian hamsters show mate preference before they engage in copulation by displaying vaginal marking, known to solicit males. [5] She often chooses to mate with an alpha male, who will flank mark (a scent-marking behaviour associated with aggression and competition [6] ) more frequently than any subordinate males present. [5]

Male offspring are at higher risk than female offspring of enduring effects from maternal social stress. [7] In the presence of a dominant pregnant female, subordinate pregnant female hamsters have the ability to reabsorb or spontaneously abort their young (most often males) in utero. [7] The subordinate females produce smaller litters overall, and any male offspring they do produce will be smaller in size than those that were produced by the dominant female. [7] After a mother hamster gives birth, normal behavior from the mother in the postpartum period can include establishing a maternal bond with the babies, the mother being aggressive to protect the babies, or infanticide in rodents of the mother to her young. [8]

The male Syrian hamster has a requirement for both hormonal cues and chemosensory cues in order to engage in copulation. Further, the integration of steroid cues (i.e. testosterone) and odour cues (relayed through the olfactory bulb) is crucial for mating. [9] It has also been shown that within the medial amygdala, the anterior and posterior regions work together to process the stimuli (odors), showing that their mating behaviour relies on the main olfactory system's communication to nuclei in the amygdala regions. [10] Their behaviour has demonstrated this phenomenon, as they are attracted to the odor of female hamster's vaginal discharge. [11] Males have even demonstrated mounting behaviour on other males who are scented with the female vaginal discharge. [11]

When one male and two females are placed in the same environment, the male is likely to engage in copulation with both females as it provides him with a reproductive advantage. [12] In all observed scenarios where there was one male and two females, he did not demonstrate preference for either female and engaged in copulation with both the females present. [12] There has been no reproductive disadvantage to the female when another female is present, other than decreased stimulation as compared to a one-male one-female situation. [12]

Interactions with others

Syrian hamsters acquire learned helplessness when they are bullied a few times by larger animal. [13] Syrian hamsters can regain lost confidence when some time passes without experiencing bullying. [13]

Interactions between male and female Syrian hamsters are influenced by the estrous cycle - in addition, their behaviour changes over the course of the 4-day cycle. Parameters for interactions that have been studied include sniffing, approaching, leaving, and following each other (male/female pair). [14] Specific to the male hamster, his response to the female can be measured by mounting behaviour, intromission and ejaculation. [15]

Under semi-natural conditions, the mating behaviours of male and female hamsters were observed during the 4-day period of estrous. [16] When they were allowed free interaction, females displayed lordosis in their own living area 93% of the time, where after 60 minutes of copulation the male would be driven out by the female while she retrieved his food supply and forced him into a corner farthest away from her nest via displays of aggressive behaviour. [16]

When a Syrian hamster is introduced to a stranger hamster in its own cage, they perform a standard sequence of acts and postures (also known as a fixed action pattern) that are agonistic by nature. [17] It has been observed that one hamster becomes the dominant and the other becomes submissive, as shown by their posture. [17] The stranger hamster was observed to be the dominant in the majority of situations, and the resident hamster was the submissive. [17]

Feeding behaviour

Food-anticipatory activity (FAA), meaning increased locomotion due to restricted feeding schedules (often found in laboratory settings), is a behaviour seen in many rodents. The Syrian hamster is one of only few exceptions to this activity. It has been found that the arcuate nucleus, ventromedial nucleus, and dorsomedial nucleus are all involved in the presence of FAA, and that Syrian hamsters in the laboratory do not demonstrate FAA because of the presence of light and the typical light cycles used in experiments. [18]

In a study of their food-hoarding behaviour, Syrian hamsters were given a limited access to food and expected to consume more in each sitting than they typically would. [19] Instead, they exhibited hoarding behaviour where they took the food during the given time period and continuously ate the food that they hoarded as though they were on a free-fed schedule. [19] This allowed them to maintain typical body weight, and mimic the adaptive feeding strategies they may use in their natural habitats.

Females have shown signs of anorexia and anxiety when separated from social interactions. [20] Social separation of hamsters has a bias toward females, thus providing a model for the differences between sexes when experiencing anorexia and anxiety in their adulthood. [20]

Laboratory behaviour

Although most all hamsters display wire-gnawing behaviour in all laboratory cage sizes, it has been shown that the more restricted the cage size, the more their gnawing behaviour increases. [21] Additionally, hamsters in smaller cages used the roof of their house as a platform more often than those in a larger cage which may suggest that they are trying to create more space for themselves within their cage. [21]

In another study, the bedding depth of hamsters and its influence on their stress and wire-gnawing behaviour was tracked by assigning 3 groups different bedding depths - 10 cm, 40 cm, and 80 cm. [22] This is due to the natural instinct that laboratory rodents have to dig. [22] Hamsters who had the 10 cm deep bedding showed significantly more wire-gnawing than any others, and the 80 cm deep bedding group demonstrated no wire-gnawing behaviour. [22] This research demonstrates the importance of having enough bedding for the hamsters to indulge their natural tendencies and have enough material to dig.

The behaviour and responses of Syrian hamsters have been observed and tested for a variety of medical-related studies as well, such as the development of the palate and incidence of cleft palate, [23] [24] the influence of retinoic acid on physical malformations in fetuses, [25] immune responses to diseases like hookworm, [26] and the effects of ingesting ethanol solution on liver composition and fatty acid accumulation. [27]

Related Research Articles

<span class="mw-page-title-main">Hamster</span> Subfamily of rodents (Cricetinae)

Hamsters are rodents belonging to the subfamily Cricetinae, which contains 19 species classified in seven genera. They have become established as popular small pets. The best-known species of hamster is the golden or Syrian hamster, 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, the winter white dwarf hamster and the Roborovski hamster.

The Coolidge effect is a biological phenomenon seen in animals, whereby males exhibit renewed sexual interest whenever a new female is introduced, even after sex with prior but still available sexual partners. To a lesser extent, the effect is also seen among females with regard to their mates.

<span class="mw-page-title-main">Australian zebra finch</span> Species of bird

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<span class="mw-page-title-main">Golden hamster</span> Species of rodent

The golden hamster or Syrian hamster is a rodent belonging to the hamster subfamily, Cricetinae. Their natural geographical range is in an arid region of northern Syria and southern Turkey. Their numbers have been declining in the wild due to a loss of habitat from agriculture and deliberate elimination by humans. Thus, wild golden hamsters are now considered endangered by the International Union for Conservation of Nature. However, captive breeding programs are well established, and captive-bred golden hamsters are often kept as small house pets. They are also used as scientific research animals.

Menstrual synchrony, also called the McClintock effect, or the Wellesley effect, is a contested process whereby women who begin living together in close proximity would experience their menstrual cycle onsets becoming more synchronized together in time than when previously living apart. "For example, the distribution of onsets of seven female lifeguards was scattered at the beginning of the summer, but after 3 months spent together, the onset of all seven cycles fell within a 4-day period."

<span class="mw-page-title-main">Hamster wheel</span> Exercise toy for hamsters and other rodents

A hamster wheel or running wheel is an exercise device used primarily by hamsters and other rodents, but also by other cursorial animals when given the opportunity. Most of these devices consist of a runged or ridged wheel held on a stand by a single or pair of stub axles. Hamster wheels allow rodents to run even when their space is confined. The earliest dated use of the term "hamster wheel", located by the Oxford English Dictionary, is in a 1949 newspaper advertisement. Squirrel cages featured in an 1885 catalog titled Catalogue of the Osborn M’F’G Co. came with running wheels for the squirrels, just like a hamster cage.

<span class="mw-page-title-main">Long-tailed paradise whydah</span> Species of bird

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<span class="mw-page-title-main">Courtship display</span> Communication to start a relationship with someone or to get sexual contact

A courtship display is a set of display behaviors in which an animal, usually a male, attempts to attract a mate; the mate exercises choice, so sexual selection acts on the display. These behaviors often include ritualized movement ("dances"), vocalizations, mechanical sound production, or displays of beauty, strength, or agonistic ability.

<span class="mw-page-title-main">Nesting instinct</span> Instinct in pregnant animals related to estradiol

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<span class="mw-page-title-main">Mate choice copying</span> Strategy used by organisms

Mate-choice copying, or non-independent mate choice, occurs when an individual of an animal species copies another individual's mate choice. In other words, non-independent mate-choice is when an individual's sexual preferences get socially inclined toward the mate choices of other individuals. This behavior is speculated to be one of the driving forces of sexual selection and the evolution of male traits. It is also hypothesized that mate-choice copying can induce speciation due to the selective pressure for certain, preferred male qualities. Moreover, mate-choice copying is one form of social learning in which animals behave differently depending on what they observe in their surrounding environment. In other words, the animals tend to process the social stimuli they receive by observing the behavior of their conspecifics and execute a similar behavior to what they observed. Mate choice copying has been found in a wide variety of different species, including : invertebrates, like the common fruit fly ; fish, such as guppies and ocellated wrasse; birds, like the black grouse; and mammals, such as the Norway rat and humans. Most studies have focused on females, but male mate copying has been also found in sailfin mollies and humans.

Female copulatory vocalizations, also called female copulation calls or coital vocalizations, are produced by female primates, including human females, and female non-primates. They are not purposeful, but instead are evolutionary and are spontaneously produced by female primates, including women, to encourage her partner to produce good-quality sperm during the mating process. Copulatory vocalizations usually occur during copulation and are hence related to sexual activity. Vocalizations that occur before intercourse, for the purpose of attracting mates, are known as mating calls.

<span class="mw-page-title-main">Sexual selection in amphibians</span> Choice of and competition for mates

Sexual selection in amphibians involves sexual selection processes in amphibians, including frogs, salamanders and newts. Prolonged breeders, the majority of frog species, have breeding seasons at regular intervals where male-male competition occurs with males arriving at the waters edge first in large number and producing a wide range of vocalizations, with variations in depth of calls the speed of calls and other complex behaviours to attract mates. The fittest males will have the deepest croaks and the best territories, with females making their mate choices at least partly based on the males depth of croaking. This has led to sexual dimorphism, with females being larger than males in 90% of species, males in 10% and males fighting for groups of females.

<span class="mw-page-title-main">Non-reproductive sexual behavior in animals</span> Non-reproductive behavior in non-human animals

Animal non-reproductive sexual behavior encompasses sexual activities that non-human animals participate in which do not lead to the reproduction of the species. Although procreation continues to be the primary explanation for sexual behavior in animals, recent observations on animal behavior have given alternative reasons for the engagement in sexual activities by animals. Animals have been observed to engage in sex for social interaction bonding, exchange for significant materials, affection, mentorship pairings, sexual enjoyment, or as demonstration of social rank. Observed non-procreative sexual activities include non-copulatory mounting, oral sex, genital stimulation, anal stimulation, interspecies mating, same-sex sexual interaction, and acts of affection, although it is doubted that they have done this since the beginning of their existence. There have also been observations of sex with cub participants, as well as sex with dead animals.

Inbreeding avoidance, or the inbreeding avoidance hypothesis, is a concept in evolutionary biology that refers to the prevention of the deleterious effects of inbreeding. Animals only rarely exhibit inbreeding avoidance. The inbreeding avoidance hypothesis posits that certain mechanisms develop within a species, or within a given population of a species, as a result of assortative mating and natural and sexual selection, in order to prevent breeding among related individuals. Although inbreeding may impose certain evolutionary costs, inbreeding avoidance, which limits the number of potential mates for a given individual, can inflict opportunity costs. Therefore, a balance exists between inbreeding and inbreeding avoidance. This balance determines whether inbreeding mechanisms develop and the specific nature of such mechanisms.

<span class="mw-page-title-main">Hamster cage</span> Enclosure that houses hamsters

A hamster cage is an enclosure designed to house one hamster. It is recommended that hamster cages are at least 5000cm² for dwarf hamster except Roborovski and 6000cm² for syrian and Roborovski, although there is evidence that hamsters experience less stress if housed in larger cages. Commercially available pens are made of wire or plastic - both of which are unsafe for hamsters. Some pet owners house their hamsters in aquarium tanks, and some make their own pens out of wood or safe materials like plexi. Laboratory hamsters, commonly known as laboratory Syrian hamsters, are housed in pens designed for scientific use. There are also special pens designed for hamster shows.

<span class="mw-page-title-main">Domestication of the Syrian hamster</span>

The domestication of the Syrian hamster began in the late 1700s when naturalists cataloged the Syrian hamster, also known as Mesocricetus auratus or the golden hamster. In 1930 medical researchers captured Syrian hamster breeding stock for animal testing. Further domestication led this animal to become a popular pet.

Syrian hamsters are one of several rodents used in animal testing. Syrian hamsters are used to model human medical conditions including various cancers, metabolic diseases, non-cancer respiratory diseases, cardiovascular diseases, infectious diseases, and general health concerns. In 2014, Syrian hamsters accounted for 14.6% of the total animal research participants in the United States covered by the Animal Welfare Act.

Elizabeth Adkins-Regan is an American comparative behavioral neuroendocrinologist best known for her research on the hormonal and neural mechanisms of reproductive behavior and sexual differentiation in birds. She is currently a professor emeritus in the Department of Psychology and the Department of Neurobiology and Behavior at Cornell University.

References

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  26. ↑ Mendez, Susana; Valenzuela, Jesus G.; Wu, Wenhui; Hotez, Peter J. (2005-06-01). "Host Cytokine Production, Lymphoproliferation, and Antibody Responses during the Course of Ancylostoma ceylanicum Infection in the Golden Syrian Hamster". Infection and Immunity. 73 (6): 3402–3407. doi:10.1128/IAI.73.6.3402-3407.2005. ISSN   0019-9567. PMC   1111885 . PMID   15908367.
  27. ↑ Cunnane, S.C.; Manku, M·S.; Horrobin, D.F. (1985). "Effect of Ethanol on Liver Triglycerides and Fatty Acid Composition in the Golden Syrian Hamster". Annals of Nutrition and Metabolism. 29 (4): 246–252. doi:10.1159/000176977. ISSN   1421-9697. PMID   4026205.{{cite journal}}: CS1 maint: multiple names: authors list (link)
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