Clumping litter works by absorbing the moisture content in your cat’s liquid and solid waste. As the litter absorbs the moisture, it forms clumps!
The first mass produced clumping cat litter was made of bentonite clay, a type of clay that does a really good job of absorbing moisture.
Clumping clay litter does its work by swelling up when it comes in contact with moisture.
That is how the clumps occur.
In its fresh form, sodium bentonite-based clumping kitty litter looks like small granules – sort of like the sand your cat might gravitate towards outdoors.