Most of the writing I'm doing on the expanded rules right now centers on spandrels, and I thought you'd like a peek at some of them.
Recall than many listed game stat of a species -- its attack type & damage, AC, MV, Species Traits -- can be used as spandrel rewards for animal adventurers of other species. And animals will be able to claim magical items by eating them.
In addition, there will be several spandrels unique to animal PCs, that can be rewarded in place of standard magical items. Here are some samples.
You can fully transform yourself into a member of one of your evolutionary ancestor species, gaining all of its inherent Species Traits for 1d5 [1d6] turns + 1 turn per level. The form you assume must actually have existed in your species’ evolutionary history, and must actually have been ancestral to your species and not from a sister taxa or mostly-unrelated extinct taxa. A monkey, for instance, cannot transform into a T. rex, but could assume the form of a dimetrodon or some other proto-mammal.
You may only assume a single form with this spandrel, which will be specified in its description; for instance, “Greater Atavism: Dimetrodon” in the above case. However, you can switch between this form and your regular form at will for the duration of the effect.
A greater atavism can be used 1d3 [1d4] times per day.
You can manifest a Species Trait from your species’ evolutionary history, gaining all of its relevant game rule effects, for 1d5 [1d6] turns +1 turn per level. The trait must actually have belonged to one of your species’ ancestor taxa and not a sister taxa or mostly-related extinct taxa. A monkey, for instance, cannot manifest the wings of a pterosaur, but could manifest the bite attack of a dimetrodon or some other proto-mammal.
You may turn this manifested Trait “on” or “off” at will for the duration of the effect. This spandrel will always grant only a single Trait, specified by its description; for instance, “Lesser Atavism: Dimetrodon Bite Attack” in the above case.
A lesser atavism can be used 1d3 [1d4] times per day.
You gain a +2 bonus on all attack rolls, lore checks, and saving throws you make while opposing the efforts of a longpaw, so long as she is within 20 feet of you.
Sprint Of The Cheetah Lords (Prerequisite: Epic Sprint Species Trait or spandrel)
Once per day, you can run in a straight line up a vertical surface, or across a body of water or gases, at any speed up to your Epic Sprint MV, provided the distance traveled is equal to or less than your Epic Sprint MV score in feet. If you find that the distance is greater than you anticipated, you cannot stop or turn, and must keep moving in a straight line until you’ve covered the maximum possible distance. At this point, you suffer whatever consequences your miscalculation entails: falling into water and risking drowning, perhaps, or suffering falling damage if tumbling from a great height.
Warding Growl (Prerequisite: Must be capable of vocalizations)
Your growl (or hiss, shriek, etc.) becomes exceptionally frightening. A character or creature who has up to, but not more than, 2 Total Levels or Hit Dice more than you must succeed on a Fear save vs. your Threat, or suffer one of the Fight or Flight effects described in Chapter 4.
This effect applies even to beings not commonly spooked by animals, such as aliens, demons, longpaws, monsters, robots, undead creatures, etc.
Weaponized Musk (Prerequisite: Musk Attack Species Trait)
In addition to its normal effects, your musk attack now inflicts damage on all creatures within its area of effect. The damage is equal to your maximum HP; for instance, if you normally have 15 HP when fully rested and healed, your musk attack inflicts 15 HP damage, regardless of your current HP. This means the damage your musk attack causes increases as your Total Level increases.
Creatures within the area of effect are entitled to Tough Poison save for half damage.