>>43522731On Normal Summon, you send any Zoodiac from the deck to the grave. You can either mill a Zoodiac to revive, or the trap card Zoodiac Combo, which can be banished from the grave to shuffle back some Zoodiacs from the grave and draw a card.
The gimmick of Zoodiacs is that each turn, their Xyz can be summoned with any one Zoodiac as material once each. Xyz are played by stacking cards on top of each other (usually 2-3 of matching level), and the cards in the stack beneath the material) are fodder for effects.
So you play the effectively vanilla Boarbow on Ratpier, then some other Zoodiac Xyz on Rat, detach Boar for a free Rat with Rat's material effect, and you can go a bunch of ways from there. Broadbull can detach a material to search any Beast-Warrior, Drancia can detach a material to destroy any card, Chakanine can detach a material to revive a Zoodiac, and Tigermortar can detach a material to attach a Zoodiac from your grave to any Zoodiac Xyz as material.
The other Zoodiacs all give stats and effects to your Zoodiac Xyz when used as material, including effect negations, piercing damage, and a one-sided D.D. Warrior Lady effect.
In addition, with two Rats you can play Brotherhood of the Fire Fist - Tiger King, the boss monster of another archetype, who searches any Fire Formation and negates all non-Beast-Warrior monster effects on the field.
Fire Formations include Tenki - a searcher for low-level Beast-Warriors, Tensu - an extra Normal Summon for Beast-Warriors, and a bunch of other less-used-in-Zoodiacs cards. They all buff all of your Beast-Warriors as well, which all of your Zoodiacs are.
Before Ratpier was limited to 1, a single Ratpier could result in a board of multiple monsters on field and cards searched to hand, with no other cost than your Normal Summon.
And they have a spell that can summon any Zoodiac straight from the deck.