Reptile & Amphibian Forums

Is rat litter size determined by genetics or by the age/condition of the female? I have a few adult rats, I don't know their age but they are giving me consistently small litters. The younger females (from these adults) that I raised from babies have given me nice large healthy babies. Would it be worth it to keep females from large litters?

Another question - how many litters on average can a female have before their production starts to slow down? How about approximate age?
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Jerry
WeiSides Zoo

I've read on the rat forums that females tend to stop producing around 18 months of age, and that as they approach that age their litter sizes go down.

I have one female who's actually over 2 years old that still gives me litters of between 12 and 15 every 4 weeks or so... She also steals everyone's pups to try and nurse them... She's my "supermom" but then her mother was the same way until she got sick and I was forced to euthanize her...The general rule is 18 months.. but there are exceptions to every rule.
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Lucien

1.1 Columbian Redtail Boa (BCI)(Sutekh and Isis)
2.1.1 Leopard geckos (2 Blizzards (Caine and Goliath), 1 Tangerine Albino (Tequila Sunrise ...Tiki for short) and 1 dbl. het blizzard x tang albino (Malice))
0.1 Savannah Monitor (Kiros)
13 rats
1 Gerbil
2 Dogs (Loki and Storm)
2 cats (Sahara and Hercules)

>>I have one female who's actually over 2 years old that still gives me litters of between 12 and 15 every 4 weeks or so... She also steals everyone's pups to try and nurse them... She's my "supermom" but then her mother was the same way until she got sick and I was forced to euthanize her...The general rule is 18 months.. but there are exceptions to every rule.
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>>Lucien
>>
>>1.1 Columbian Redtail Boa (BCI)(Sutekh and Isis)
>>2.1.1 Leopard geckos (2 Blizzards (Caine and Goliath), 1 Tangerine Albino (Tequila Sunrise ...Tiki for short) and 1 dbl. het blizzard x tang albino (Malice))
>>0.1 Savannah Monitor (Kiros)
>>13 rats
>>1 Gerbil
>>2 Dogs (Loki and Storm)
>>2 cats (Sahara and Hercules)
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Jerry
WeiSides Zoo