Hamster and Gerbil Lecture

How many hamsters should you house together?

1 (solitary and can be aggressive)

What are the most nocturnal rodents?

Hamsters

Why do we know hamsters are very photoperiodic?

They are very nocturnal

What are some of the problems with housing hamsters?

Great escape artists

What happens if you store a hamster <40F?

They will go into hibernation

Describe hamster inregumentary?

Lots of loose skin

Why do we have minimum space requirements for rodents?

Animal welfare act, use the Guide to know how much you need

Why should cedar bedding be avoided with hamsters/

Oils can cause respiratory irritation, derm irritation, poss, and elevated liver enzymes

What enrichment can you do for hamsters?

Housing hideouts with igloos or PVC pipe

What should hamsters eat?

Seeds, grain, vegetable supplements

What do hamsters do with their food?

They hoard it in their bedding (do not use a hopper)

Why do you have to place hamsters food on the floor?

Because they like to hoard it in a corner

How much fiber do hamsters need?

Not much, so a pelleted feed is ok

Why do you want to avoid seed based diets?

Rodents wont eat seed hulls and will pick and choose seeds

Can be used as treats

T/F hamsters are copraphagic?

True

T/F gerbils are coprophagic?

False

How many digits do hamsters have?

4 on the front

5 on the back

What special glands do hamsters have?

Hardarian glands

Flank glands

What do flank glands do?

More mature in males and consists of sebaceous glands, terminal hairs, and pigment cells

They convert testosterone to dihydrotestosterone

Describe buccal pouches?

Two well developed cheek pouches on lateral aspect of the head and neck. Will store, bedding, and neonates

Why are buccal pouches immunologically privileged?

Limited lymphatic drainage to regional lymph nodes

What is the research application of buccal pouches?

Cheek pouch supports long-term survival of many foreign tissues which is useful for human oral cancers

Hamsters also have few spontaneous occurring tumors

What is the disease implication of buccal pouches?

Pouch impactions

Where is the brown fat?

Between scapulas and spreads ventrally under the scapulas

Also found around adrenals and kidney

What does brown fat do?

Thermogenesis, especially during hibernation

Warms capillary beds passing through brown fat

Why do we not use brown fat as a site of injections?

They are very vascularized

What is the dental formula for hamsters and gerbils?

Same as mice and rats

Where is enamel?

Labial surface of incisors and everywhere molars

What is the maxillary : mandibular ratio?

1:3

What is the problem with malocclusion?

Must manage it for life

What teeth at birth and are hypsodont?

Incisors

Describe the stomach?

Forestomach and glandular stomach are separated by a muscular sphincter

What hamsters have gallbladders?

All except chinese hamster

How large is a hamster cecum and colon?

Larger than other rodents

What are the lung lobes of a hamster?

1 left and 5 right

What infections are hamsters resistant to?

Pulmonary infections

What part of the respiratory tract is similar to humans histologically?

Trachea

What is the research implication of hamster respiratory tract?

Studies of chronic bronchitis and emphysema of humans

Long term smoking effects

When do hamsters go through puberty?

90-100 gms weight

Females: 6-8 weeks

Males: 8-12 weeks

What is he female repro cycle?

Estrous every 4 days, continually polyestrous and spontaneous ovulators

No post partum estrus

How long is hamster gestation?

15-16 days

What is the research application of hamster repro system?

Short gestation and large litters so used in teratology and birth defect studies of humans

When do you wean hamsters?

21 days

What is day 1 of the estrous cycle in a hamster?

3 hours of proestrus

12 hours of estrus

Obulation on 18-19 hrs on day one

4 hours of metestrus

Vaginal discharge on morning of ovulation

How long does diestrus last?

From days 2-4 of cycle

What is the causative agent of antibiotic induced enterotoxemia?

Clostridium difficile

Describe the behavior of gerbils

Nonaggressive, curious, monogamous pairs, burrowers, nocturnal (but somewhat diurnal)

What do escaped gerbils do?

Do not hide

What do agitated gerbils do?

Audible stomp

How do gerbils sit?

Semierrect posture

How do you touch gerbils tails?

Do not grab ever at the tip. If grabbed t base, be careful. very susceptible to degloving and necrosis

How should you handle gerbils?

Scoop them up (hate being on back)

Can be scruffed

Why do gerbils not get ring tail?

They can tolerate lower humidity

What is different in gerbil anatomy/

Elongated rear limbs (metatarsals)

Furred tail

Long strong claws

Describe the ventral marking gland?

Ventral midline sebaceous gland that is androgen dependent and more prominent in males

What can happen to ventral marking glands/

Infection or neoplastic

What is the common hamster used for research?

Mesocricetus auratus

What hamster does not have a gall bladder?

Crietulus griseus (chinese hamster)

What dental research are hamsters used in?

Dental caries since crowns of molars allow for fine food retention allowing for dental carries

What GI research are hamsters used in?

Inducible pancreatic tumors are very comparable to humans

How do you sex hamsters?

Anogenital distance is longer in males

Pointed posterior in males

Darker area around flank glands

How many urogenital openings do females have?

3 (urethra, vagina, rectum)

When do you breed females?

3 days after seeing vaginal discharge on day 2 of estrus (this is day 1 of the 4 day cycle)

Breed late in the day (1 hour before beginning of dark cycle)

How long is gestation in hamsters?

16-17 days

When can you detect pregnancy?

10 days due to abdominal distension and rapid weight gain

Lack of vaginal discharge

How long do you need to avoid disturbing pups after parturition?

7 days due to cannabolism

When do you wean and sex pups?

3 weeks old b/c breeding can start at 6-8 weeks

What is the research application of antibiotic induced enterotoxemia?

Model for pseudomembranous colitis in humans

When does antibiotic induced enterotoxemia of C. diff occur?

2-10 days after using inappropraite Ab therapy

What antibiotics cannot be given?

Lincomycin, clindamycin

Ampicillin

Vacnomcyin

Erythromycin

Cephalosporins

Gentamicin

Penicillins

What antibiotics can you give?

Enrofloxacin

Chloramphenicol

Tetracyclines

Sulfonamides

What are the C/S of C. diff?

Acute onset enteritis, profuse diarrhea

Hx of Ab therapy

Fatal typhlitis

What is the pathology of C. diff?

Necrotizing typhlitis

Hemorrhagic necrosis d/t toxin production

What causes illness from C. diff?

Toxin A (enterotoxin) and toxin B (cytotoxin

What causes C. diff?

Antibiotics reduce normal flora and C. diff is opportunistic

What is AAC?

Antimicrobial associated colitis (C. diff)

What are the differences in AAC in hamsters and humans?

it is in the distal ileum, cecum, and proximal colon in hamsters

Distal colon in humans

Hamsters do not get pseudomembranes

What are all the research uses of hamsters?

Dental carries, tumor and oral tumor studies, pancreatic tumors, chronic bronchitis and emphysema, teratology and birth defects, AAC

T/F if syrians are bred on postpartum estrus there will be a delay of implantation causing gestation to be 25 days?

False, there is no postpartum estrus

What is the scientific name for gerbils?

Meriones unguiculatus

How do you hold a gerbil?

Over back with index and middle fingers around the neck with your thumb and ring fingers around the body 

How can you deglove a hamster?

Improper handling

How do you treat a degloved tail?

Amputation

What humidity do you want for gerbils?

30-50% because they are from dry environments

Will also not get ring tail easily

T/F gerbils have a persistent thymus?

True

Describe gerbil kidneys?

Long loops of henle and renal papillae

Very concentrated urine

Lower H2O intake

Very large adrenal glands

How do you sex male gerbils?

No nipples

Dark scrotum

Greater anogenital distance

Larger ventral marking gland

How many nipples do gerbils have?

Females only have 4 pairs (8 total)

Why are gerbils used for hearing research?

Large bullae

When do gerbils reach maturity?

F: 9-12 weeks

M: 9-18 weeks

Describe gerbil estrus cycle

4-7 days

Continually polyestrous and spontaneous ovulators

How long is gerbil gestation?

23-26 days unless bred on postpartum estrus then up to 48 days due to delayed implantation

What is the average litter size of gerbils?

5

T/G gerbils cannabilize often?

False

When do you wean gerbils?

21-30 days

What causes facial eczema in gerbils/

Increased porphyrin secretions due to stress and mechanical trauma

This causes a secondary Staph infection

What are C/S of facial eczema?

Erythema then alopecia then moist dermatitis

How do you treat facial eczema in gerbils?

Correct stressors, topical Ab

Hardarian gland removal

What antibiotic is TOXIC to gerbils (not dysbiosis)?

Streptomycin like neomycin and penicillin-dihydrostreptomycin

What are the C/S of streptomycin toxicity?

Acute ascending paralysis causing respiratory arrest and death in minutes