I have hamsters at home, and their usual food is chometz. I can feed them with cornflakes and other kitniyot for a short period (about a week, maybe more), but not for a long time. Hamsters store food inside their mouth and can some time spit it out.

The question is: Can I just clean their cage from chometz before Passover, or I must ensure that they had finished all chometz inside their mouth too?

P.S. I'm aware about CYLORing, you don't have to remind me that once more :)

  • Mmmmmm.... Hamster-cheek chometz ....
    – Isaac Moses
    Commented Mar 18, 2012 at 2:21
  • 1
    Nifsal meiachilat hamster?
    – Double AA
    Commented Mar 18, 2012 at 3:04
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    @DoubleAA, it's clearly not that, though.
    – Isaac Moses
    Commented Mar 18, 2012 at 3:59
  • @IsaacMoses After they spit it out, they eat it again?
    – Double AA
    Commented Mar 18, 2012 at 4:22

3 Answers 3


The amount of chametz that one must eat to violate the issur kares of chametz on Pesach is a mashehu - any amount.

However, one does not violate the issur of owning chametz on Pesach unless / until one owns a k'zayis of chametz.

Many Rishonim and Acharonim dispute the scope of the statement in Pesachim 45a-b that two half-k'zayis pieces of chametz in a home do NOT combine.

I have no clue how much food a hamster stores in its mouth, or how much of that food is chametz. There are many different versions of k'zayis (as explained in the linked article on k'zayis above). If you're going to use the large measurement l'chumra, and eat a very large piece of matzah at the seder, you should be able to rely on that exact same measurement l'kulah, in which case I highly doubt that there is a full 28.8 cubic centimeters of chametz stuck in any one hamster's mouth!

  • 3
    I'm not sure about "If you're going to use the large measurement l'chumra..., you should be able to rely on that exact same measurement l'kulah". Often, recommended practice accounts for each of two halachic disputants l'chumra. Also, although you may be correct that we are only required to be rid of k'zesim of chametz, I think a very common practice is to be rid of even less. (This is but one of many chumros relating to chametz that the Jewish nation has accumulated over the years.)
    – msh210
    Commented Mar 18, 2012 at 16:47
  • @msh210 If the questioner has a strong relationship with a rav, rebbe, or specific subsect, he should follow his minhag on whatever a k'zayis is. If not, then following normative practice to consider 28.8 cm3 a k'zayis on Pesach makes perfect sense. Once that is your definition of a k'zayis, it works l'kula as well. The main thing is consistency.
    – user1095
    Commented Mar 18, 2012 at 18:40
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    You get karet for a chatzi shiur? I don't think so.
    – Double AA
    Commented Mar 21, 2012 at 22:24

After CYLORing the question I was told that because enjoying from chometz is also forbidden (not only eating), so if my pet is not hungry because it eats chometz that stored in his mouth - it makes me enjoy from chometz. Therefore, kitniyos diet should be started enough time before Passover, in order to eliminate chometz from their mouthes.

  • Unless you sell your chametz (and any animals that eat chametz, which is included in most versions of the mechirat chametz contract)... in which case some non-Jew's hamster is benefiting from the stored Chametz
    – Hahu Gavra
    Commented Mar 21, 2012 at 21:38
  • @HahuGavra thanks for the idea. However, see my comment to your answer.
    – jutky
    Commented Mar 21, 2012 at 21:41

Perhaps this is why the document used to sell chametz to the gentile says (I'm quoting the Shu"t Beis Av edition):

גם כל בעלי חיים הניזונות מחמץ בהמות גסות או דקות סוסים וציפורים ועופות

  • My children enjoy playing with hamsters, especially at Passover vacation when they spend more time at home. So, I prefer them to remain in my property. Anyway, thanks for the information that precisely suits my case.
    – jutky
    Commented Mar 21, 2012 at 21:39

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