Digimon

The life span of a Digimon
Digimon live for about 15 to 20 days in Digimon World time, depending on how well you care for them. During that time you may digivole as many as five times, from baby form to ultimate form.

Baby form:
All Digimon take these forms to start with. Because they are newly hatched, both Baby and In-training forms are weak and virtually useless in battle. Both are restricted to the simple Buble attack, where the tiny Digimon spits water bubbles at the enemy. It may be cute, but it's neither effective nor strong. Even with maxed out stats, a baby or In training form can inflict only a few points of damage with Bubble.

Your best bet is to take these cute little Digimon to your local gym and try to build up their stats for Digivolution to Rookie form. Feed them a lot and watch out for signs of tiredness.

Note: The four Baby Digimon form digivole into four corresponding in-training forms. For example a Botamon (Baby) always digivolves into Koromon (In training).