Small Furries Flashcards
Rodents are in the order rodentia. They live everywhere but Antarctica and NZ. There are 5 suborders, name them…
Myomorpha = mouse like Hystericomorpha= porc like e.g. Guinea pigs, chinchilla, edgy Sauriomorpha= squirrel like Anomualuromorph Castorimorph
How many teeth do Myomorpha have?
State the formula
Describe the teeth compared to hystericomorphs
16
I1/1, C0/0, PM0/0, M3/3
The nerve its under the gum so allows us to bur, incisors are constantly growing, aradicular (no true root), elodont (cont grow)
Compared to hystericomorphs- they have no premolars, and only their incisiors continuously grow
How many teeth do hystericomorphs have?
State the formula
How do these differ to Myomorphs?
20
i1/1, c0/0, pm 1/1, m3/3
Hystericomorphs have premolars and Myomorphs don’t, this is why Myomorphs have 4 fewer teeth.
Compared to Myomorphs, there premolars and molars grow too!!
Describe some small animal GI adaptions
They are monogastric, the stomach is split into forestomach and glandular stomach by a ridge.
They have a large caecum
Most practice copraphagy to increase their vitamin B and K
They don’t vomit
Don’t starve them before surgery because they have a high metabolic rate
Describe some respiratory adaptions
They are obligate nasal breathers.
They have 1 lobe on the left and 4 on the right (hamsters have 5)
They have a short respiratory tract
They’re oxygen requirement is high. To achieve this….They have a high resp rate, more alveoli so an increased surface area, and high chest wall compliance
The oxygen Haem sat curve shifts right so there is more oxygen offloading
How could you sex the main rodent species?
Anogenital distance (bigger in males) = most often used
Nipples present in female mice and rats ONLY
gerbils have a pigmented scrotum
Hamsters have large testes
Guinea pigs genitals are i shaped in males, Y shaped in females
Why is sexing chinchillas hard?
Because the penis and clitorus look similar
How do you determine the stage of oestrus
Cytology of vaginal secretions
Flush, dry, stain, count lymphocytes and epithelial cells
When they are in season you’d mainly see cornified epithelial cells
What’s the purpose of the cop plug formed 8-12 hours after mating?
Increase mating success
Why are rodents suseptible to dehydration, hypothermia and hypoglycaemia?
They have a high SA to BW ratio
They have a high metabolic rate
How do the reproductive systems differ in Myomorphs and hystericomorphs
hamsters, rats, mice and chinchillas (and also rabbits) have 2 cervixes, they are duplex. There is one cervix to each horn.
Guinea pigs have been reported to have both duplex and bicornate.
Dogs cats and ferrets have bicornate
Explain how litters differ in myos and hystericos
Myomorph offspring are altricial they require lots of maternal care, they’re born hairless, they don’t move around much, they have large litter numbers and a short gestation period (18-25)
Hystericomorphs are opposite. They are precocial. Gest length (59-150)
Why are rats incisiors yellow
Due to iron pigment
Do rats have a a harderian gland?
Yes
Do rats have a gall bladder?
No
