Having a familiar can help a wizard, both with his magic and in his dealing with animals of the familiar type. This page gives some talents a familiar can confer to a wizard.

Easy spell casting
If a spell in the familiar’s domain is cast, get a bonus of 1 to the casting roll.

Easy spell learning
The mage can learn spells in the familiar’s domain for half the XP that it would cost normally.

Understand animals
horses
The mage gets a rudimentary understanding of what animals of the familiar’s type think and speak about. Those animals act toward the mage as if he is one of their kind. Note that this does not always mean that they are friendly. Protecting the territory, fights for leadership of the pack, and so on, are just as likely to happen.

Animal Friend
Animals of the familiar’s species will have a friendly disposition toward the mage.

Change perspective
By concentrating hard, the mage can see through his familiar’s eyes, hear through his familiar’s ears. This usually requires a Will Power test.

Familiar talents
Furthermore, there are some skills and talents that are linked to the sort of creature that the familiar is. These are mentioned for each type of familiar, in the list of familiars. The mage can learn these talents and skills too.