The next time, he has a look at the springs. Not their surroundings - their water.
He puts a dish of blueberry water in the middle of the cave, away from the spring's usual location, and also a dish of ordinary, unflavored water.
The next time he is at the cave, he brings some lemon and some lime flavored water from rivers of these flavors.
He puts a bowl of blueberry water outside the cave exit, and waits.
He moves the bowl about a foot father away. He sits outside the cave and waits.
A troop of three poofs ventures past the edge of the cave, bumping into each other as they navigate the unfamiliar terrain. They have to use each other as stepping-stones to hop into the bowl and drink, but when the first two have had enough, they roll out and let the last one hop up onto them to get in.
Kanim keeps the bowl full, and keeps moving it farther and farther away from the cave entrance.
He stops moving it. He wants to see if anything will be lured to stay out of the cave.
He adds a cucumber bowl, farther from the blueberry one.
It is welcome to stay there till Kanim has to make refills.
With this and further informed observations, Kanim concludes that the water is the only special cave thing the Gentle Creatures require, and determines that it will be quite possible for the girls to keep Gentle Pets if they routinely fetch both kinds of water or just produce it at home. A divided spring which will do each kind costs a pentagon.