One of the first things that caught my eye in Indonesia was spotting cats with shorter tails than usual. Some just had something that seemed like a bump. I asked some locals! It is a genetic selection.
The cats brought from Europe during the Dutch conquest, was interbred with the Japanese bobtail breed. Nowadays cats on the islands carry a "shorttailes gene" and are born with tails in different sizes.

Some people coming to Indonesia worry that the cats are not treated well or even think that Indonesian people cut the tails of their cats. Many Indonesians believe that cats with short tails/no tails are better ratters and they will look after these cats. (feeding them, etc.) This genetic trait (short or kinked tails) has therefore been selected in this way.
And... even without a tail a cat can stay perfectly balanced!