Mouse
Pikachu
Its nature is to store up electricity. Forests where nests of Pikachu live are dangerous, since the trees are so often struck by lightning.
Worm
Caterpie
Perhaps because it would like to grow up quickly, it has a voracious appetite, eating a hundred leaves a day.
Tiny Turtle
Squirtle
Squirtle's shell is not merely used for protection. The grooves on its surface help minimize resistance in water.
Lizard
Charmander
The flame that burns at the tip of its tail is an indication of its emotions. The flame wavers when Charmander is enjoying itself.
Dragon
Dratini
It's still weak, so it lurks on the floor of bodies of water, eating whatever food sinks down and living a quiet life.
Sleeping
Snorlax
It doesn't do anything other than eat and sleep. When prompted to make a serious effort, it apparently displays awesome power.
Freeze
Articuno
Articuno is a legendary bird Pokémon that can control ice. The flapping of its wings chills the air. Snow will fall.
Seed
Bulbasaur
Bulbasaur can be seen napping in bright sunlight. There is a seed on its back. The seed grows progressively larger.