T3: Lab Animals Flashcards
What are the characteriscs of rats and mice
-easily tamed and easy to care for
-social species
-same-sex pairs or groups are best
-Live an average 2-3 years
-9-11 inches for body length
-nocturnal animals
What are the family names for mice and rats?
Mus musculus: home mouse (family cridetidae)
Rattus norvegius: Brown norway rat
Rattus Rattus: black rat
melanocytes with two types of melanin:
eumelanin (black or brown) and phaeomelanin (yellow)
Other than size, mice, and rats have the same,,,,
requirements for housing
- wire cage
-glass cages are not good for ventilation 965-75F and 30-70% humidity
-do not use cedar shavings the oil can kill rats
Describe the skeleton
- 13 pairs of ribs
-clavicles
-front/rear feet: five digits each
-rat: the first digit on front feet is very small
Describe the dentition of rats
dental formula: 2 (1/1 incisors, 3/3 molars)
incisors: single pair, pigmented layer of enamel
-grown and worn down : malocclusion
What is the harderian gland
-behind eye
-stressed: creates porphyrin resembling red tears
– chromodacryorrhea (formal name)
Describe the digestive system
rats: cannot vomit, a ridge of the stomach may block the esophagus
- no gallbladder
- omnivores
-take in 10-12 grams daily
mice: no appendix
-omnivore
- 2-4 grams per day
Urethea opens in..
- in the penis in the male (urogenital orifice)
- in the genital papilla near the base of the clitoris (not in the vagina)
Describe the male urogenital system
- sperm plug
- the os penis (penis in the genital papilla)
- rats have open inguinal rings
Describe the urogenital system of the female
female
- rates have 2 cervixes, one for each horn
-mice have now cervix
-vaginal closure membrane: usually in immature females disappears prior to sexual maturity
-anogenital distance is shorter in females than in males (way to sex them)
rats: 6 pairs of nipples
mice: only 5 pairs
Describe the basic repro physiology
- polyestrous
-spontaneous ovulators
-estrous every 4-6 days
-estrus at night/day 3
-vaginal plugs by normal males
Gestation Length
-mouse: 18.5-21 dogs
-rat: 21-23 days
pups are altricial
sexual maturity
-mouse: M (5-7 weeks) F(4-5 weeks)
- rat: M (6-7 weeks) F (5-6 weeks)
What is a milk spot
presence of milk in the stomach
What are the basic characteristics of hamsters?
most common Syrian hamster
solitary, must live alone
- a wheel for running, enclosures to hide and sleep in, tunnels and paper towels to make a nest with
-litterspan: 1.5 to 2 years
-sexually mature females are aggressive to other females and to other males.
What is the formal name of the golden hamster?
mesoricertus auratus: domesticated in 1939
What do cheek pouches do for hamsters?
- to transport/store food or nest material
- extend back over the neck
- can be everted (turned inside out)
What do flank glands do for hamsters
in males: mark territory
- will scratch at glands
in females not as easily identified but are associated with the estrous cycle e
Describe the hamster basics for reproduction
mammary gland: 7 pairs of nipples, mammary tissue is not as extensive as in rats and mice
reproduction:
- Sexual maturity: M (6-8 weeks) F (same)
- 4-day estrus cycle
- ovulation occurs 6-10 hrs after onset of estrus
-lordosis, 8 hrs before ovulation
-post-ovulatory discharge
How do you know if copulation has occurred? How long is gestation?
check for sperm (vaginal) plug
- 15-18 days (the shortest!)
What are the basic characteristics of guinea pigs?
- Cavia porcellus
-they can be housed together
-social animals and very vocal
-lifespan 5-7 years
-adults: 10 ins long, 2-3 lbs
-tail less
-precocial
Describe why Guinea pigs got their names and who they are most closely related to
cavy is more accurate but European settlers thought they looked like pigs and they were sold for the monetary unit “guinea” in England
-non burrowing, herbivores
-closely related to chinchillas and porcupines
- cleft upper lip (philtrum)
How should you house and feed a guinea pig?
The biggest cage possible, do not use wire mesh for the cage floor: bedding
- vitamin C supplement
Describe the anatomy of the guinea pig
- vestigial clavicles
- 4 digits on each front foot, 3 on each back foot
- incisors are normally white, unlike those of many other rodents
-nose- breather - female: only one pair of nipples/mammary glands in the inguinal region
-sperm/vagina plug
Describe the reproduction of a guinea pig
-puberty: F (2 months) M (3 months)
-16-day estrous cycle; spontaneous ovulation
-vaginal closure membrane open for 2-3 days
-gestation: 59-72 days
The pubic symphysis (pelvis) in non-pregnant guinea pigs is closed: dystocia occurs if the symphysis has not been stretched
