Ch 18: Mice

Which of the following statements regarding outbred mice is FALSE?

A. Out red mice have been bred for maximum heterozygosity

B. Outbred mice have a stable overall genetic makeup

C. Outbred mice all share the same genes as every other mouse in the population

D. Outbred mice are created by mating a closed population (animals at least 4 generations) of unrelated animals

C. Outbred mice all share the same genes as every other mouse in the population

True or False:

Mice less than 10 days of age may be caught by cupping the hands around the whole body or by picking up a group of pups together with a small amount of nesting material.

True

True or False:

Both respiration and heart rate in the mouse are easily measured by observing or feeling the chest

False; they are too rapid and require electronic recording devices

True or False:

An acceptable management technique that may reduce or prevent fighting among male mice housed together is to house young males together from weaning

True

True or False:

The “F1” on the end of a hybrid designation indicates that this is the second generation

False; “F1” indicates first generation of mating scheme

True or False:

Inbred strains usually have larger litters than outbred stocks

False; they usually have small litters

True or False:

By 7 days of age, mouse pups are fully furred and their eyes are open

False; by day 10 to 14

What are hybrid mice?

A. The offspring of two different strains

B. The offspring of two albino mice

C. The offspring of wild mice

D. The offspring of an agouti mouse and an outbred stock

A. The offspring of two different strains

Which statement is TRUE?

A. Genetically modified ‘nude’ mice have a hyperactive immune system

B. Mice should be fasted before surgery to prevent vomiting

C. Toe clipping is the best practice for individually identifying mice

D. Female mice exposed to constant light may stop having an estrous cycle

D. Female mice exposed to constant light may stop having an estrous cycle

Male neonates can be distinguished from female neonates by their larger __________

Genital papilla

List five signs of pain, distress, or illness in mice.

Ruffled fur

Hunched posture

Dehydration

Inactivity

Weight loss

Staining around eyes, ears, nose, or personal region

What is the average weight of an adult male mouse (grams)?

20-40 grams

What is the average weight of a newborn mouse (grams)?

1-1.5 grams

What is the average lifespan (months) of a mouse?

12-36

Do female or male mice have a longer anogenital distance?

Male

Do female or male mice have a shorter and genital distance?

Female

Female mice come into heat within how many hours after partirition?

14-28

How long is the gestation period (days) in a mouse?

19-21 days

What is the average litter size in mice?

4-12

What is the average weaning age (days) in mice?

21-28 days

What could happen if you disturb a litter after birth?

Mother cannibalizes newborns

What occurs when you fail to wean litters on time?

Overcrowding

Inbred mice typically have smaller/larger litters.

Smaller

Outbred mice typically have smaller/larger litters.

Larger

What age (days) do female mice start breeding?

50 days

List three forms of environmental enrichment commonly given to mice.

Group housing

Nesting material

Foraging material

Structure for hiding

Skin tenting and sunken eyes are signs of what health problem?

Dehydration

Mice are most active at night. What is the term used to describe being active at night?

A. Nocturnal

B. Diurnal

C. Diuresis

D. Circadian

A. Nocturnal

What is the scientific name of the common house mouse?

Mus musculus

Newborn mice are ________, meaning they are born hairless with eyes and ear canals closed.

Altricial

List three examples of permanent methods of identifying mice.

Ear notching

Numbered ear tags

Tail or toe tattoo

Implantable, subcutaneous microchip

What is the term for coming into heat 24 hours after giving birth?

Postpartum estrus