Hamsters

Question 1

What is the taxonomy of hamsters?

Answer 1

Order: rodentia
Suborder: myomorpha
Family: critetidae
Sub-family: circetinae
Genera: mesocricetus (main one), criteus, cricetulus, phodopus, tscherskia

Question 2

What is the most common species of hamster seen in practice? What are some other species seen?

Answer 2

Syrian (golden) hamster (mesocricetus auratus)
- has many color variations
- there is an angora (or teddy bear) long haired variety

Other species: siberian (russian), european (black belly), armenian (grey), chinese “dwarf”, and long tailed

Question 3

What is unique about the black belly hamster?

Answer 3

3X the size of other hamsters, has a black belly (duh)
-primary species sold in Europe

Question 4

Describe the general history of hamsters

Answer 4

1930- one female with offspring taken from Syria to Israel and bred, almost all syrian hamsters originate from this original stock
1931- first syriann hamsters taken to britain
1938- first syrian hamsters taken to US (to east coast)
1948- first chinese hamsters shipped to US (to west coast)
1960s- several inbred strains of syrians were developed for research

Question 5

What type of research were hamsters used for?

Answer 5

Dental, cancer, immunology (xenotransplants), infectious disease, hypothermia, parasitic disease, teratology, repro, vascular physiology, genetics (DCM)
-used more for research before they enters pet trade industry

Question 6

How long is the adult hamster? How much do they weigh?

Answer 6

5-7 inches long
-50-150 g

Question 7

What is the average lifespan of a hamster?

Answer 7

2-3 years

Question 8

How much urine do hamsters produce on average?

Answer 8

5.4-8.4 mL/day
-AKA a lot
-have to change cage bedding frequently (2X per week at least)

Question 9

Describe the basic anatomy and physiology of hamsters

Answer 9

-short tailed, short haired
-short blunt nose with small, rounded ears
-most with dark eyes, some with red (albinos)
-cheek pouches present which can evert
-stomach has a proximal non-glandular portion and distal glandular portion
-large cecum, cecal fermenter, coprophagic (can be source of bacteria after antibiotic use), sensitive to antibiotics

Question 10

What exotics formulary was recommended?

Answer 10

Carpenters

Question 11

What is the function of the cheek pouches in hamsters?

Answer 11

Used to transport feed and nesting material
-these are an immunopriviledged site
-these can be everted- must sedate them

Question 12

Describe the teeth of hamsters

Answer 12

-prominent incisor teeth
-same dental formula as rats and mice
-molars do not grow continuously

Question 13

What is the difference between the stomach of hamsters compared to rats and mice?

Answer 13

There is a greater demarcation between the non-glandular and glandular portions of the stomach

Question 14

What occurs when you give antibiotics to hamsters?

Answer 14

Ileus and diarrhea

Question 15

Describe the flank sebaceous glands of hamsters

Answer 15

-patches located on the flank
-they are present in both sexes, but only functional in males
-involved in marking territory and mating behavior
-secretion causes the hair in the flank area to become wet

Question 16

Describe the behavior of hamsters

Answer 16

-borrowers in the wild- require materials to do this (paper towel rolls, PCV piping)
-crepuscular activity (most active in mornings and evenings)
-deep sleepers and can become aggressive when disturbed
-females often more aggressive than males
-permissive hibernators at temps <48 degrees
-escape artists that do not return to cage

Question 17

Describe the diet of hamsters

Answer 17

-omnivores
-eat multiple times a day (need to be given food ad libitum as well as water-they drink and urinate a lot)
-coprophagous- provides source of vitamin B and K
-lab diets are nutritionally balanced (but should provide them a variety of foods so they dont get picky)

*dont know specific nutrient requirements

Question 18

What is the ideal temperature for a hamster?

Answer 18

70-72 degrees
-dont need special temps- do well at room temp

Question 19

How can you improve the enrichment of hamsters?

Answer 19

-plenty of cage room with a running wall/wheel (dont give wire wheels as they can predispose to pododermatitis)
-they have a circadian rhythm with daily bursts of energy

Question 20

How should you restrain hamsters?

Answer 20

-cupping in hand or towel
-grip on scruff of neck and back (be aware they have a lot of skin, mobility of head is extreme)
-always support their bottom

Question 21

How can you easily gender hamsters?

Answer 21

Anogenital distance

Question 22

Describe the reproduction of hamsters

Answer 22

-4 day estrous cycle
-estrus (heat) starts at night
-post ovulatory discharge on the 2nd day
-females in estrus will exhibit lordosis 8 hrs before ovulation
-gestation is 15-18 days (shortest of all lab animals)
-litter size of 4-12 pups
-females may cannibalize pups if disturbed (stress response)

Question 23

Describe neonatal development of hamsters

Answer 23

-birth weight of 2-3 g
-born hairless with eyes and ears closed
-ears open at day 5
-begin eating solid food on day 7-10
-hair starts emerging on day 9
-eyes open on day 15
-weigh 35-40 g at weaning
-weaning at 17-21 days
-can sex them at 5-7 days (should try to separate them early to prevent breedings in the future)

Question 24

What are the options for collecting blood from hamsters?

Answer 24

Jugular, cephalic, retroorbital (not very humane), saphenous, mandibular, toe nail clip (not appropriate)
- maximum volume of 0.8-1 mL

Mandibular or saphenous recommended under sedation

Question 25

Describe proliferative enteritis of hamsters

Answer 25

-aka wet tail
-caused by clostridium dificile mainly, but also lawsonia intracellularis, campylobacter fetus ssp jejuni, and E coli
-causes lethargy, anorexia, ruffled coat, typhlitis, diarrhea, dehydration and death
-often occurs post antibiotic therapy (most commonly), stress, poor diet, and recently weaned individuals
-lesion seen is hyperplasia of ileal epithelium
-transmitted by fecal oral route
-treatment: gentamycin- consider C/S testing

Question 26

What are the main causes of pneumonia in hamsters?

Answer 26

Pasteurella pneumotropica, strep pneumonia and sendai virus (murine parainfluenza-hamsters are carriers but rarely show clinical signs)
-causes lethargy, anorexia, respiratory distress, nasal and ocular discharge
-trt: antibiotics

Question 27

What are the primary tumors found in hamsters?

Answer 27

Malignant
- lymphosarcoma (viral induced, can affect skin GI or kindey - warts enteritis or pyelonephritis)
-reticulum cell sarcoma- lymph nodes
-carcinoma of intestine and adrenals

Benign-usually found post mortem
-gastrointestinal polyps
-adenomas of adrenal cortex

Question 28

What is the primary cause of death in old hamsters?

Answer 28

Amyloidosis
- >85% occurrence in hamsters over 18 months
- etiology unknown
- causes anorexia, weight loss, PUPD, and proteinuria
-kidney is most common site of deposition
-occasionally amyloid in other organs (spleen, liver and adrenals)

Question 29

What is tyzzers disease?

Answer 29

Caused by clostridium piliforme
-gram negative spore forming rod
-most common in mice
-stress induced disease
-clinical signs similar to wet tail (anorexia and weight loss, scruffy hunched up appearance, profuse diarrhea and dehydration)
-causes acute mortality with severe and/or bloody diarrhea and perianal staining (much more acute than wet tail)

Question 30

Describe lymphocytic choriomeningitis

Answer 30

• a rodent borne viral disease (arenaviridae)
• more common in mice than hamsters
• virus spreads in urine, droppings, saliva and nesting material
• potentially zoonotic**- causes fever and muscle aches
• 2-5% of US human population has antibodies against this
  -clinical signs in hamsters are variable, may include lethargy, anorexia, rough haircoat, weight loss, death
  -can be infected for 8+ months, and may infect offspring

Question 31

What are some of the internal parasites of hamsters

Answer 31

-giardia
-trichomononas
-spironucleus
-sympacia obvelata and s muris (pinworms- most commonly seen)
-hymenolepis nana and diminuta (tapeworms)

*hopefully not seen in pet populations as all are bred in captivity

Question 32

What external parasites can be seen in hamsters?