European Hamster Flashcards
Genus and species of European hamster.
Cricetus cricetus
Why was the European hamster initially used in research?
Wild-caught animals from a West German industrial area found to have bronchogenic squamous cell carcinoma. Susceptible to N-diethylnitrosamine (DEN) with development of resp tumors. Believed to be a more suitable model than Syrian for highly concentrated and prolonged smoke-inhalation studies.
Why is the European hamster provided strict legal protection in all European countries?
Bern Convention of 1979 established European hamster as a strictly protected species in Appendix II, and later became listed in Appendix IV of the Habitats Directive.
How are European hamsters sourced?
No breeding colonies in U.S. Sources from European institutional research colonies.
Are European hamsters widely used in research today?
No, most use is in studies of hibernation.
Describe European hamster behavior in the wild.
Nocturnal, hibernate in winter.
What is the size of European hamsters?
Largest species, at least 3x that of Syrians, with males larger than females.
Describe the appearance of European hamsters.
White faces and feet. Reddish brown dorsums, cranioventral black patches, and caudolateral white patches.
Describe the personality of European hamsters.
Very aggressive, easily frightened, will attach and bite. Easier to handle when bred in captivity.
Describe the social order in European hamster litters.
Defined social order, with heaviest male dominant.
What is the average life span of a research-bred European hamster and wild hamster?
Research-bred: Female 34 months, male 31 months. May be due to higher incidence of neoplasia in males.
Wild: 4-10 years
What is the diploid chromosome number of the European hamster?
2n = 22
Describe the diet and water intake of European hamsters.
Water: 5mL/100g
Food 2.9g/100g in summer, 1.8g/100g in winter
Mainly seed eaters, but will consume standard lab rodent diets.
When do European hamsters reach sexual maturity? What is the length of their estrus cycle, gestation length, litter size, and weaning age?
Sexual maturity = Females 80-90 days; Males 60 days
Estrous cycle = 4-6 days
Gestation = 18-21 days (captured); 15-17 days (lab borne)
Litter size = 7-9
Weaning = 25-28 days
How long does each period of the estrous cycle last?
Proestrus for a few hours, estrus for 1-3 days, metestrus of 6h, and diestrus for 2-4 days.
How is estrus determined? How is test mating performed?
By vaginal smears and test-mating. Steel mesh divider used to keep the pair separated. Female is only receptive for a short period during estrus, and aggressive during other 3 stages. If no aggressiveness noted, hamsters may be mated.
How many litters do females have per year?
1-2 litters/year. Sexual activity not observed in winter months, with the sexes very aggressive to each other.
How heavy are European hamsters?
At weaning, 75g.
6-month old females 300g and males 400g.
What anatomic changes occur during the non-breeding season?
Female’s vagina is closed and the male’s scrotum is decreased in size with testes in the abdominal cavity.
The critical photoperiod, at which time gonadal regression is induced, is when?
Between 15 and 15.5 hours.
Are these animals true hibernators? What changes in chemistry values are noted?
Yes. Affects thrombocytes, and leukocyte value.
Describe spontaneous neoplasia in older European hamsters.
Common, with up to 70% incidence by 2 years of age. Slightly more prevalent in males.
Most frequent, in descending order: Leukemias and lymphomas, adrenal pheochromocytomas, and granulosa cell tumors in females.
Describe thymic tumors in European hamsters.
Resembled benign human thymomas, but were associated with large number of mast cells, unlike human tumors.
Describe cysts in European hamsters.
Prone to developing in peritoneal cavity, particularly in the liver. More often in females than males. Can also seen in cecum, ovaries, kidney, and colon.
Secondary bacterial infections with Corynebacterium, Staph, and Pasteurella pneumotropica and multocida are associated with what in European hamsters?
Fistulated abscesses in head and jaws.
The development of malocclusion, osteomyelitis, and dysplasia increases with age and suggests that European hamsters could be used in what research? What are secondary sequela?
Dental. Complicated by secondary bacterial infections, which can be fatal.
