When you look in-game at the Fighter Board (in the Felyne kitchen at the right), there are different options to select. Choose the first option, "Development". When you select a Felyne you can choose the following options:
OPTION - DESCRIPTION Martial Arts - The Felyne gains levels like in missions. Strength - The Felyne gains attack power. Toughness - The Felyne gains defense power. Fencing - The Felyne gains both attack power and defense power. Meditation - The Felyne gains skill points. Rest - The Felyne increases its loyalty.