Ch 19: Rats

What is the approximate normal body weight for an adult male rat?

300-500 grams

What is the approximate normal body weight for an adult female rat?

250-300 grams

Which of these anatomical characteristics distinguishes rats from mice?

A. A shorter esophagus

B. Two upper and two lower incisors

C. The lack of a gallbladder

D. The presence of premolar teeth

C. The lack of a gallbladder

Which rat is albino, has a wide head, long ears, and a tail that is half its body length?

A. Sprague-Dawley

B. Wistar

C. Long-Evans

D. Fischer

B. Wistar

True or False:

Male rats cannot be pair housed or they will fight

False; male rats can be co-housed

True or False:

Molar teeth of rats grow continuously

False; only the incisors grow continuously

True or False:

Rats are nocturnal and are never active during the day

False; they have periods of activity day and night

True or False:

Red staining around the eyes and nose is due to porphyrin, a secretion that can be normal for rats, but at other times may indicate a condition of stress

True

True or False:

Toe clipping is the recommended identification method for adult rats

False; only on neonates when other methods aren’t feasible

True or False:

Rats can be “tickled” by caretakers, reducing stress during handling and restraint

True

What are some of the common inbred strains of rats?

Fischer 344

Lewis

Which rat stock is also known as the “hooded” rat?

Long-Evans (LE) because the fur on its head is pigmented

What problem can occur if you pick rats up by the tip of the tail?

The skin on the tail may rip off or slough off (degloving)

List two biological features that rats have in common with mice.

Do not vomit

No canines or premolars

One pair of upper and lower incisors

Malocclusion common

How long does a female rat’s estrous cycle last?

4-5 days

Cervical dislocation should only be performed on rats weighing less than what?

200 grams

Which of the following statements is TRUE?

A. Rat pups are born fully furred and with their eyes open

B. Rats can be harem mated with one female and several males in a cage

C. Rats can be weaned at 14-17 days of age

D. Rats are inquisitive and enjoy complex environments where they can climb and play

D. Rats are inquisitive and enjoy complex environments where they can climb and play

What is the scientific name for the common laboratory rat?

Rattus norvegicus

How much food and water does an adult rat usually consume in a day?

5 grams of food'

8-11 mL of water

True or False:

Rats are social animals and benefit from group-housing as well as provision of nest-building material for environmental enrichment

True

What problem occurs if rats are kept in wire-bottom cages for long periods of time (a year, or more)?

Pododermatitis (foot lesions)

How frequently should rat cages be changed?

Twice a week