There are two types of critters you can find for points.

Matuvus [small], blue lizard/frogs] whistle if you go near them. Use "Look" mode to find them, and watch them until they wave at you.

The Tribelles [red, three-leafed plant-critters] disappear if startled. Walked carefully or strafe up, touch them, and they should give up points.

*** Noteworthy, try to be energized when you find these critters, will give you double points.