The Karni Mata Temple in Deshnok is about 30km from Bikaner and is dedicated to a goddess who was considered the reincarnation of Durga. The temple is famous, most of all, because there are a ton of rats living there, and they have completely lost their fear of people. People head to this sacred place to pray and put out food for the rats, which are considered reincarnations of the Charan, a group of traditional musicians. They say it's good luck to see the rats in the temple and that they'll bring you happiness.
During religious festivals, like the Aarti, they spoil the rats with treats and sweets.