LO1 - Small Mammals Flashcards
What are Myomorphs?
Includes rats, hamsters and gerbils
They have 16 teeth with no premolars and rooted molars
What are Caviomorpha?
- Includes Guinea Pigs and Chinchillas
- Herbivores which eat highly abrasive materials
- 20 teeth with open rooted molars
- Have precocious young, born fully furred, capable of living independently
What are Sciuromorpha?
Includes chipmunks, squirrels and prairie dogs
20-22 teeth with rooted molars
What is Coprophagy?
When an animal re-ingests its own excreted faeces
Observed in rats, mouse, hamsters, Guinea pigs and chinchillas
Unnecessary with feeding modern diets but innate behaviour stimulated by anal reflex
Rats - Normal Parameters
Life Span - 2.5 to 3.5 years
Weight - 400 to 800g
Heart Rate - 260 to 450bpm
Respiratory Rate - 70 to 150bpm
Temperature - 38*
Rats - Factors affecting their Temperature?
- they have poor heat tolerance as they have few sweat glands, and are unable to pant
- tail and ears are important for heat dispersion
- death at temperature above 37*
Rats - Dentition Facts
- incisors are for fighting, holding food, gnawing and excavating burrows
Rats - Skeletal System
- 7 Cervical, 13 Thoracic, 6 Lumbar, 4 Sacral, 27 to 31 Coccygeal Vertebrae
- long tail is sensitive to pain, and important for balance and thermoregulation
Rats - Male Reproductive System
- testicles from 3 to 4 weeks of age
- no nipples
Rats - Female Reproductive System
- anogenital distance shorter than in males
- have 6 mammary glands
Rats - Respiratory System
Involved with respiration, humidifying, filtering incoming air, and olfaction
Rats - Digestive System
- omnivores
- GI transit time 12 to 24 hours
- diastema, helps close off back of mouth to allow gnawing on hard substances
- ridge between oesophagus and the cardiac region of the stomach which makes regurgitation of food material almost impossible
Rats - Injection Sites
Lateral tail vein
Lateral saphenous vein
Hamsters - Normal Parameters
Life Span - 2 to 3 years
Weight - 80 to 120g
Heart Rate - 280 to 412bpm
Respiratory Rate - 70 to 80bpm
Temperature - 36.2* to 37.5*
Hamsters - Digestive System
- omnivores
- cheek pouch
- vomiting impossible sue to ridge between oesophagus and the cardiac region of the stomach
- stomach has 2 compartments the non-glandular and glandular, distinguished by muscle sphincter
Hamsters - Male Reproductive System
- distance between opening of anus and opening of genital tract is longer in male than female
- no nipples in males
- males have external testes, retained in scrotum
Chinchillas - Normal Parameters
Life Span - 10 to 12 years
Weight - 400 to 600g
Heart Rate - 100 to 150bpm
Respiratory Rate - 40 to 80bpm
Temperature - 38 to 39*
Chinchillas - Skeletal System
- sensitive whiskers
- delicate ears
- dark prominent eyes
- can see in poor light
Chinchillas - Digestive System
- monogastric herbivores
- small narrow oral cavity
- tongue is continuous with soft palate and the entrance to the pharynx via a small hole, the palatel optimum
- diastema
- prone to dental problems
Chinchillas - Extra Waste Factors
- eat faecal pellets at night and then caecotrophs between 8am and 2pm
- can die from constipation
- D+ is caused by over indulgence
Chinchillas - Male Reproductive System
- no true scrotum
- 3 pairs of mammary glands
- penis supported by small bone known as baculum
Chinchillas - Female Reproductive System
- anogenital distance is shorter
- seasonal polyoestrous and spontaneous ovulators
- uterus has 2 horns, each of which terminate into cervix
- 2 cervix leading into single vagina
- 3 pairs of mammary glands
Mice - Normal Parameters
Life Span - 2 to 3 years
Weight - 20 to 40g
Heart Rate - 500 to 600bpm
Respiratory Rate - 100 to 250bpm
Temperature - 37.5*
Mice - Skeletal System
- large dark eyes
- poor sight
- delicate ears
