Explainer on Sizes of Kitties

[Prokofy Neva]

Yes, I've read the Google page handbook.
Yes, I've read whatever is out there on Google about kittycats.
No, I don't want to join a group because there's always so much chatter, annoying mods, and requests for help in paying rent these days in EVERY group that I can't tolerate it, sorry!
No, I can't come to inworld events on a schedule, I have multiple RL jobs to do.

Hence, the forums.

Can someone point me to a quick and concise explainer about the cats' sizes? I only found this by accident when I saw cats being born and they seemed really big or really small.

Are they merely random feature, available from any kittycat on a random basis? Or?

I have a cat just born whose name from the system is "Gem". But *is* she a "gem"? Or is that just her random name that happens to be a coincidence? Here are her stats:

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[02:38] KittyCats - Gem: https://kittycats.ws
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♀ Gem

҉ 1 day ♥ 0% ☺ 71% ↯ 20% 모☁ 1%

Fur: Siamese - Blue
Eyes: Midnight Sky (Shape: Mysterious | Pupil: Big)
Shade: Natural
Tail: Genesis
Ears: Mysterious
Whiskers: Silver (Shape: Boo Boo)
Size: 16 cm (6.2 inch)

Version: 1.56
Owner: Prokofy Neva
ID: fe04b3df-4957-4bb6-24d3-78a5f88d2f69
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MOM: Mara
Fur: Genesis - Ginger
Eyes: Genesis Sunshine (Shape: Mysterious | Pupil: Big)
Shade: Natural
Tail: Genesis
Ears: Mysterious
Whiskers: Silver (Shape: Curious)

DAD: Saelig
Fur: Genesis - Ginger
Eyes: Midnight Sky (Shape: Curious | Pupil: Big)
Shade: Natural
Tail: Genesis
Ears: Mysterious
Whiskers: Silver (Shape: Guitar)
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For some weeks, when I've been looking at this info, it would give inches or centimeters, but not a label like "petite" or "bigger da big" as it used to do. I don't know why. But that means I couldn't tell what these animals were.

So if it says "16 cm" is that "normal" and in fact not a littler size?

Finally, I wonder if the offer to get a MegaPuss after you send in 300 cats to the Menagerie (I think I read that somewhere) is still good. I decided I want to pursue that. And that's because I simply can't figure out how to get the money generated from sending cats in the Menagerie to work "inworld". Is that money only available to feed cats in the Cattery?