Water specifically. It helps mask the smell, and it's a frequent spot for one of their favorite foods, frogs. They also fish whatever is left in the water, if any. A lot gets caught on their tails, which frequently dip into the water.

Surprisingly, they're extremely clean creatures, even with their dietary habits! They rarely carry any known passable diseases, even rabies! In fact, the biggest issue to look for is Metabolic Bone Disorder, or MBD, which is a sign of low calcium, and causes twisting of the bone structure, often leading to death. There is no cure, just slowing the spread.