You or an ally can ride your animal companion as long as it is at least one size larger than the rider. If it is carrying a rider, the animal companion can use only its land Speed, and it can't move and Support you on the same turn. However, if your companion has the mount special ability, it's especially suited for riding and ignores both of these restrictions.

The following are the base statistics for a young animal companion, the first animal companion most characters get. You adjust these statistics depending on the type of animal you choose. A companion has the same level you do. As you gain levels, you might make further adjustments as your companion grows more powerful. Animal companions calculate their modifiers and DCs just as you do with one difference: the only item bonuses they can benefit from are to Speed and AC (their maximum item bonus to AC is +3).

To advance a young animal companion to a mature animal companion (usually a result of one of your class feat choices), increase its Strength, Dexterity, Constitution, and Wisdom modifiers by 1. Increase its unarmed attack damage from one die to two dice (for instance 1d8 to 2d8), and its proficiency rank for Perception and all saving throws to expert. Increase its proficiency ranks in Intimidation, Stealth, and Survival to trained, and if it was already trained in one of those skills from its type, increase its proficiency rank in that skill to expert. If your companion is Medium or smaller, it grows by one size.

To advance a mature animal companion to a nimble animal companion, increase its Dexterity modifier by 2 and its Strength, Constitution, and Wisdom modifiers by 1. It deals 2 additional damage with its unarmed attacks. Increase its proficiency ranks in Acrobatics to expert. It also learns the advanced maneuver for its type. Its attacks become magical for the purpose of ignoring resistances.

To advance a mature animal companion to a savage animal companion, increase its Strength modifier by 2 and its Dexterity, Constitution, and Wisdom modifiers by 1. It deals 3 additional damage with its unarmed attacks. Increase its proficiency rank in Athletics to expert. It also learns the advanced maneuver for its type. If your companion is Medium or smaller, it grows by one size. Its attacks become magical for the purpose of ignoring resistances.

The species of animal you choose is called your companion’s type. Each companion type has its own statistics. The Size entry indicates your companion’s starting size as a young animal companion. Following the size entry are the companion’s unarmed attacks, and then its ability modifiers. The Hit Points entry indicates the companion’s ancestry Hit Points. The Skill entry indicates an additional trained skill your companion has. The Senses entry lists your companion’s special senses. The Speed entry gives your companion’s Speeds. The Special entry, if present, lists any other special abilities your companion has, for example whether it often serves as a mount and is particularly appropriate for mounted classes, such as the champion. The Support Benefit entry indicates a special benefit you gain by Commanding the Animal to use the Support action (see below). The Advanced Maneuver entry indicates a powerful new action your companion learns how to use if it becomes a nimble or savage animal companion.

Specialized animal companions are more intelligent and engage in more complex behaviors. The first time an animal gains a specialization, it gains the following: Its proficiency rank for unarmed attacks increases to expert. Its proficiency ranks for saving throws and Perception increase to master. Increase its Dexterity modifier by 1 and its Intelligence modifier by 2. Its unarmed attack damage increases from two dice to three dice, and it increases its additional damage with unarmed attacks from 2 to 4 or from 3 to 6.

Each specialization grants additional benefits. Most animal companions can have only one specialization.

A list of all animal companion specializations can be found here.

Your familiar's save modifiers and AC are equal to yours before applying circumstance or status bonuses or penalties. Its Perception, Acrobatics, and Stealth modifiers are equal to your level plus your spellcasting ability modifier (Charisma if you don't have one, unless otherwise specified). It can't make Strikes, but it can use trained skill actions for skills for which it adds your spellcasting ability modifier. If it attempts an attack roll or other skill check, it uses your level as its modifier. It doesn't have or use its own ability modifiers and can never benefit from item bonuses.

Your familiar has 5 Hit Points for each of your levels.

Your familiar is Tiny.

Your familiar has low-light vision and can gain additional senses from familiar abilities. It can communicate empathically with you as long as it’s within 1 mile of you, sharing emotions. It doesn’t understand or speak languages normally, but it can gain speech from a familiar ability.

Your familiar has either a Speed of 25 feet or a swim Speed of 25 feet (choose one upon gaining the familiar). It can gain other movement types from familiar abilities.

Each day, you channel your magic into two abilities, which can be either familiar or master abilities. If your familiar is an animal that naturally has one of these abilities (for instance, an owl has a fly Speed), you must select that ability. Your familiar can’t be an animal that naturally has more familiar abilities than your daily maximum familiar abilities.