Updated: Dec. 30 (2023)
Dwarf
Dwarf, dr/dr
Two copies of The Spontaneous Dwarf Rat gene
Chromosome: 20
RVG description:
Dwarf is an effect of stunted growth and while other dwarf types have health issues the Dwarf found in the fancy is healthy, maybe even more healthy than standard sized rats as it seems that the Dwarf gene inhibits the growth of tumors.
Dwarf can be ID'ed from birth in some cases but most breeders can ID them after a few weeks.
Dwarf will have smaller feet and a shorter, thinner tail. They weight around 80-170 g. with the average weight around 120 g. in adulthood. Some lines do have tendencies to be overweight due to their production of ghrelin (the hunger hormone). It seems some Dwarfs have what is considered to be a normal to high production of ghrelin, but being under half the size of their standard counterparts, normal to high is just too much for such a small size.
Interestingly the eyeball of Dwarf seems to be regular in size which makes the eyes appear larger on Dwarfs.
Another thing I've noticed is the Dwarf tail and its cleanliness. Very rarely do I see a dirty Dwarf tail.
Sources:
Pictures from Spunky Rats Rattery, NezumiYa Rattery, and Igloo Rats
Two copies of The Spontaneous Dwarf Rat gene
Chromosome: 20
RVG description:
Dwarf is an effect of stunted growth and while other dwarf types have health issues the Dwarf found in the fancy is healthy, maybe even more healthy than standard sized rats as it seems that the Dwarf gene inhibits the growth of tumors.
Dwarf can be ID'ed from birth in some cases but most breeders can ID them after a few weeks.
Dwarf will have smaller feet and a shorter, thinner tail. They weight around 80-170 g. with the average weight around 120 g. in adulthood. Some lines do have tendencies to be overweight due to their production of ghrelin (the hunger hormone). It seems some Dwarfs have what is considered to be a normal to high production of ghrelin, but being under half the size of their standard counterparts, normal to high is just too much for such a small size.
Interestingly the eyeball of Dwarf seems to be regular in size which makes the eyes appear larger on Dwarfs.
Another thing I've noticed is the Dwarf tail and its cleanliness. Very rarely do I see a dirty Dwarf tail.
Sources:
- Genetics of the Norway Rat, Growth and Longevity, Dwarf-1, Dwarf-2 (not SDR)
- Gene Complex Controlling Growth and Fertility Linked to the Major Histocompatibility Complex in the Rat (Dwarf-3) (not SDR)
- Lifespan extension in the spontaneous dwarf rat and enhanced resistance to hyperoxia-induced mortality (SDR)
- Mammary tumorigenesis in growth hormone deficient spontaneous dwarf rats; effects of hormonal treatments (SDR)
Pictures from Spunky Rats Rattery, NezumiYa Rattery, and Igloo Rats