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. [1]
Choice tests with Syrian hamsters (Mesocricetus auratus) have shown that they prefer larger wheels; the animals chose a wheel diameter of 35 cm (14 in) over 23 cm (9.1 in), [2] which itself was preferred over 17.5 cm (6.9 in). [3]
Hamsters showed no preference between a relatively uniform running surface made of plastic mesh and a surface made of rungs spaced 9 mm apart, although they did prefer the mesh compared to rungs spaced 12 mm apart, most likely because of the wider space between the rungs allowed their legs to slip through. [2] The hamsters neither preferred nor avoided wheels that had small "speed bumps" installed along the running surface to provide environmental enrichment. [2]
Choice tests with mice have also shown a preference for larger wheels (17.5 cm over 13 cm in diameter) and a preference for plastic mesh over rungs and over solid plastic as a running surface. [4] More acrobatic species, such as the canyon mouse (Peromyscus crinitus) and the deer mouse (Peromyscus maniculatus) can develop preferences for wheels that force the animals to jump, such as square wheels or wheels with hurdles along the running surface. [5] [6] [7]
Like other rodents, hamsters are highly motivated to run on wheels; it is not uncommon to record distances of 9 km (5.6 mi) being run in one night. Other 24-h records include 43 km (27 mi) for rats, 31 km (19 mi) for wild mice, 19 km (12 mi) for lemmings, 16 km (9.9 mi) for laboratory mice, and 8 km (5.0 mi) for gerbils. [8] Hypotheses to explain such high levels of running in wheels include a need for activity, substitute for exploration, and stereotypic behaviour. However, free wild mice will run on wheels installed in the field, which speaks against the notion of stereotypic behavior induced by captivity conditions. [9] Alternatively, various experimental results strongly indicate that wheel running, like play or the endorphin or endocannabinoid [10] release associated with the 'runner's high', is self-rewarding. [8] [11] [12] Wheel use is highly valued by several species as shown in consumer demand studies which require an animal to work for a resource, i.e. bar-press or lift weighted doors. [8] [13] This makes running wheels a popular type of enrichment to the captivity conditions of rodents.
Captive animals continue to use wheels even when provided with other types of enrichment. In one experiment, Syrian hamsters that could use tunnels to access five different cages each containing a toy showed no more than a 25% reduction in running-wheel use compared to hamsters housed in a single cage without toys (except for the running wheel). [14] In another study, female Syrian hamsters housed with a nestbox, bedding, hay, paper towels, cardboard tubes, and branches used a wheel regularly and benefitted from it as indicated by showing less stereotypic bar-gnawing and producing larger litters of young compared to females kept under the same conditions but without a wheel. [15] Laboratory mice were prepared to perform more switch presses to enter a cage containing a running wheel compared to several meters of Habitrail tubing or a torus of Habitrail tubing. [16]
Running in wheels can be so intense in hamsters that it may result in foot lesions, which appear as small cuts on the paw pads or toes. [17] [18] Such paw wounds rapidly scab over and do not prevent hamsters from continuing to run in their wheel.
A hamster in a running wheel equipped with a generator can generate up to 500 mW electric power, enough for illuminating small LED lamps.[ citation needed ]
Voluntary wheel running is one of the most widely used indicators of activity and wake-time in research on circadian rhythms and other aspects of chronobiology. [19] Miniature running wheels have even been used to measure the circadian locomotor activity of cockroaches. [20] [21] For rodents, running wheels are easier to set up and automate than other techniques of activity recording such as bar-gnawing [22] and spring-suspended or knife-edge balanced cages. [23]
In rodents, voluntary exercise is almost always measured by the use of wheels. This makes running wheels the tool of choice in research on the effects of exercise and voluntary activity on metabolism, obesity, and pain. [24] [25] [26] [27] [28]
The neurotransmitter systems involved in wheel-running behavior have received considerable study. [29] Recent evidence suggests that changes in both dopaminergic and serotonergic tone alter running-wheel activity. For example, one study in mice has shown that several antidepressant medications (all of which directly or indirectly enhance serotonergic tone) suppress running-wheel activity without suppressing general locomotion. [30] The endocannabinoid system also contributes to wheel running in a sex-specific manner in rodents. [31] Mice from lines that have been selectively bred for high levels of voluntary wheel running have altered responsiveness to drugs that alter dopamine and endocannabinoid signalling, and enlarged midbrains. [32]
Tierärztliche Vereinigung für Tierschutz (TVT) recommends wheels should be at least 20 cm (8") for dwarf hamsters and at least 30 cm (12") for Syrian hamsters, since smaller diameters lead to permanent spinal curvatures, especially in young animals. They also recommend a solid running surface because rungs or mesh can cause injury. [33] It has been published in several books about small pet care as far back as 2000 that rungs and mesh wheels can cause injuries. [34] [35] [36] [37] [38]
Most wheels are constructed of steel, wood or plastic, each having advantages and disadvantages. Solid wheels are safer for all animals because the animal's feet or legs cannot get trapped and injured between rungs. There are wheels in all these materials that are solid. Plastic wheels are fine for some animals. However, some rodents (e.g. gerbils or degus) will quickly chew and destroy plastic wheels but not steel versions.
Guinea pigs cannot use exercise wheels, and attempting to use one may cause injury to a guinea pig. [39]
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A related exercise device, the hamster ball, is a hollow plastic ball into which a pet can be temporarily placed. The ball allows the pet to freely roll around on the floor to explore and exercise while preventing escape.
Recent theory suggests that hamster balls are not ideal for exercise outside of the cage. The balls prevent the rodent from using touch (whiskers) and smell to navigate the area. [40] It also restricts airflow and can catch toes or tails in the slits meant for airflow. [41]
A related exercise device is a running disc. This is a rotatable shallow bowl, or slightly concave disc, which is set at an angle to the horizontal. [42] Some commercial refuges for caged rodents have a disc mounted on the roof at a slight angle. The rodents run on the rim of the disc in a similar way to running in hamster wheels.
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.
Chronobiology is a field of biology that examines timing processes, including periodic (cyclic) phenomena in living organisms, such as their adaptation to solar- and lunar-related rhythms. These cycles are known as biological rhythms. Chronobiology comes from the ancient Greek χρόνος, and biology, which pertains to the study, or science, of life. The related terms chronomics and chronome have been used in some cases to describe either the molecular mechanisms involved in chronobiological phenomena or the more quantitative aspects of chronobiology, particularly where comparison of cycles between organisms is required.
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.
A fancy mouse is a domesticated form of the house mouse, one of many species of mice, usually kept as a type of pocket pet. Fancy mice have also been specially bred for exhibiting, with shows being held internationally. A pet mouse is inexpensive compared to larger pets, and even many other pet rodents, but mice are comparatively short-lived: typically only 2 to 3 years.
The steppe lemming or steppe vole is a small, plump, light-grey rodent, similar in appearance to the Norway lemming, but not in the same genus. The steppe lemming eats shoots and leaves and is more active at night, though it is not strictly nocturnal. In the wild, it is found in Russia and Ukraine in steppes and semiarid environments. Fossil remains of this species have been found in areas as far west as Great Britain.
Rodents are commonly used in animal testing, particularly mice and rats, but also guinea pigs, hamsters, gerbils and others. Mice are the most commonly used vertebrate species, due to their availability, size, low cost, ease of handling, and fast reproduction rate.
Hamster balls are hollow spheres made of clear plastic into which hamsters, gerbils, degus and other small rodent pets are placed, allowing them to run around outside their cages without the risk of running away or getting lost under furniture. They are designed to provide hamsters with exercise. Balls produce an audible rumble across most surfaces, making them easier to locate even when out of sight.
Conditioned place preference (CPP) is a form of Pavlovian conditioning used to measure the motivational effects of objects or experiences. This motivation comes from the pleasurable aspect of the experience, so that the brain can be reminded of the context that surrounded the "encounter". By measuring the amount of time an animal spends in an area that has been associated with a stimulus, researchers can infer the animal's liking for the stimulus. This paradigm can also be used to measure conditioned place aversion with an identical procedure involving aversive stimuli instead. Both procedures usually involve mice or rats as subjects. This procedure can be used to measure extinction and reinstatement of the conditioned stimulus. Certain drugs are used in this paradigm to measure their reinforcing properties. Two different methods are used to choose the compartments to be conditioned, and these are biased vs. unbiased. The biased method allows the animal to explore the apparatus, and the compartment they least prefer is the one that the drug is administered in and the one they most prefer is the one where the vehicle is injected. This method allows the animal to choose the compartment they get the drug and vehicle. In comparison, the unbiased method does not allow the animal to choose what compartment they get the drug and vehicle in. Instead, the researcher chooses the compartments.
Serge Daan was a Dutch scientist, known for his significant contributions to the field of Chronobiology.
A preference test is an experiment in which animals are allowed free access to multiple environments which differ in one or more ways. Various aspects of the animal's behaviour can be measured with respect to the alternative environments, such as latency and frequency of entry, duration of time spent, range of activities observed, or relative consumption of a goal object in the environment. These measures can be recorded either by the experimenter or by motion detecting software. Strength of preference can be inferred by the magnitude of the difference in the response, but see "Advantages and disadvantages" below. Statistical testing is used to determine whether observed differences in such measures support the conclusion that preference or aversion has occurred. Prior to testing, the animals are usually given the opportunity to explore the environments to habituate and reduce the effects of novelty.
Consumer demand tests for animals are studies designed to measure the relative strength of an animal's motivation to obtain resources such as different food items. Such demand tests quantify the strength of motivation animals have for resources whilst avoiding anthropomorphism and anthropocentrism.
Michael Menaker, was an American chronobiology researcher, and was Commonwealth Professor of Biology at University of Virginia. His research focused on circadian rhythmicity of vertebrates, including contributing to an understanding of light input pathways on extra-retinal photoreceptors of non-mammalian vertebrates, discovering a mammalian mutation for circadian rhythmicity, and locating a circadian oscillator in the pineal gland of bird. He wrote almost 200 scientific publications.
A hamster cage is an enclosure designed to house one hamster. It is recommended that hamster cages contain at least 100 x 50 cm, although there is evidence that hamsters experience less stress if housed in larger cages. Commercially available pens are made of wire or plastic. Some pet owners house their hamsters in aquarium tanks, and some make their own pens out of wood or plastic storage bins. 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.
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 hamster behavior refers to the ethology of the Syrian hamster.
Gulf Hamstery was a hamstery which established the commercial Syrian hamster industry in the United States. It operated between 1946 through the early 1950s and was located in Mobile, Alabama.
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.
A cat exercise wheel is a large wheel that a cat either runs on or walks on for exercise or play. A cat wheel looks like a large hamster wheel: the wheel turns from the weight of the cat. A wheel can be used for enrichment or to exercise high energy indoor cats. The wheels are generally 120 cm in diameter, with a depth of 25 cm. There are several pioneering brands, such as Cat One Fast and Tirica Wheels.
Johanna H. Meijer is a Dutch scientist who has contributed significantly to the field of chronobiology. Meijer has made notable contributions to the understanding of the neural and molecular mechanisms of circadian pacemakers. She is known for her extensive studies of photic and non-photic effects on the mammalian circadian clocks. Notably, Meijer is the 2016 recipient of the Aschoff and Honma Prize, one of the most prestigious international prizes in the circadian research field. In addition to still unraveling neuronal mechanisms of circadian clocks and their applications to health, Meijer's lab now studies the effects of modern lifestyles on our circadian rhythm and bodily functions.
Nicholas Mrosovsky was a Canadian zoologist known for his research in the fields of homeostasis, chronobiology, and sea turtle biology. He spent his whole professional career at the University of Toronto. His laboratory was notable for its seminal investigations of the influence of behavioural arousal on circadian rhythms. He was also the founder, in 1976, of Marine Turtle Newsletter. He received a Guggenheim Fellowship in 1973, and in 1993 he was elected a Fellow of the Royal Society of Canada.
