Animals roam the land, spreading and roaming thanks to the freedom they have gained in movement and striving so as not to crowd each other. They multiply over the years and increase in number. If they were crowded into a narrow area where their ancestors were, they would enter into a battle for sustenance with them and annihilate themselves. Nature plays an important role in these movements, as there is neither permanent cold nor permanent heat, but rather they are seasons that follow one another, so the animal must choose between two paths: either to leave the place to where the green plants are, or to spend the entire season in inactivity and dormancy until the earth survives with its plants, and not for most. Animals are capable of this inactivity for a long period of time, and even a few days of starvation destroy and kill them.