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Brown rat


The brown rat, also referred to as common rat, street rat, sewer rat, Hanover rat, Norway rat, ... Stories of rats attaining sizes as big as cats are exaggerations, .... by a factor of three and a h...

Rat Reproduction: Mating, Gestation, Birthing, and Growth


Rats do not have a breeding season, although very hot or cold temperatures will reduce breeding. .... In rats, the average litter size is 6-13 pups. The first sign is ...

20 Things You Didn't Know About... Rats | DiscoverMagazine.com


Dec 7, 2006 ... Jack Black the royal rat catcher, Jacko the world-champion rat killer, rats ... females can only have up to 4 litters in a life time, and the litter size ...

Part 1 Biology - National Fancy Rat Society


Nov 26, 2012 ... Rats can have big litters of 14 or more and two rats can become 100 in ... to mount his own mother successfully due to the difference in size.

Pest Control : Brown Rat


The brown rat can be found native through out the UK and tends to be heavily ... The litter size does vary but an average litter size is 8 with approximately 6 litters  ...

Rat - Are You Attracting Rats and Mice to Your Yard - Department of ...


The house mouse, roof rat, and Norway rat can reproduce year-round when adequate food ... with and average litter size of 4 to 7 pups. Rats can reproduce up ...

Influence of litter size on the postnatal growth of rat pups: is there a ...


Environ Res. 2009 Nov;109(8):1021-7. doi: 10.1016/j.envres.2009.07.015. Epub 2009 Sep 16. Influence of litter size on the postnatal growth of rat pups: is there ...

sex ratios and litter size in the laboratory rat - Journal of Heredity


SEX RATIOS AND LITTER SIZE IN THE. LABORATORY RAT. J. F. KlDWELL AND H. J. WEETH*. THE chromosome theory of sex de- termination leads to the ...

The Rationale for Culling of Rodent Litters


Reduction of Litter Size: ' "The value of culling or not culling for detection of effects on ... tinely culled rat litters to four/sex or five/sex on Postnatal. Day 4, 5, or 6 in ...



The Rat and Mouse Club of America (RMCA) Rat FAQ. ... LITTER AND BEDDING ..... The average size litter is 12, but numbers from 1 to 22 are possible.

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AFRMA - Breeding & Stuff - Large Litter of Rat Babies


What is the normal litter size for rats? Do they always have this many?! Is the mother rat going to be able to care for 16 babies? What will I need to do for her?

Mice & Rat Reproduction - Animal Hospitals USA…


Sexually mature male mice and rats usually exhibit prominent scrotum. ... Litter sizes average 10-12 pups, though it is not unusual for a female's first litter to be ...



Various factors concerned in the regulation of litter size and total reproductive ... litter size have been fairly extensively studied in rats and mice, although most.