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The cat's clavicle, or collarbone, does not connect with other bones but is buried in the muscles of the shoulder region. This lack of a functioning collarbone allows them to fit through any opening the size of their head.

Very interesting, I did not know that information, it's my first kitten. Thank you!

The claws on the cat’s back paws aren’t as sharp as the claws on the front paws because the claws in the back don’t retract and, consequently, become worn.