Quadruped Races (5e Variant Rule)
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Hey all, here's some help developing Quadruped Races. In general, quadruped races have their own traits (Which you'd put on their individual pages), but have a few traits that are general to all of them, displayed here to make things easier for DMs looking to use them. As the DM, you can use some or all of these traits or make your own based off them to enhance the game. If making pages on this wiki for a quadruped race, you can link this page to avoid having to restate anything redundant on it.
Squeezing: Quadruped races usually can't crouch easily or otherwise make the actions that let them squeeze, so if using the squeezing rule (Wherein characters can enter areas one size smaller than their own but with penalties related to it), than quadruped races cannot squeeze, except to get low to the ground and crawl under objects. Openings that aren't lowered ceilings (Or the like) that require squeezing can't be traveled through by quadruped races, and certain quadruped races (Such as horses or giraffes, but why though?) can't even do that.
Encumbrance: To make it simple, regardless of how inventory is managed, quadruped races are always able to carry twice as much as non-quadruped races of the same Strength score and size. However, this is only partially true. Many quadruped races can't easily manipulate items placed in things like saddlebags and the like that are on them, and usually don't have pockets of their own. Unless otherwise stated on the individual race's page, assume that items that aren't already out of their bags can't be reached by them, unless if the bag is explicitly made to allow them access. This is because normally those types of bags are built to be opened at the top, not the side, which requires awkward reaching and messing about. Such races CAN still mess with their inventory, but have to take the bags in question off first.
Size: Size category for quadruped races is measured from the most forward point on the head to the most backward part of their other end, usually a tail, though some creatures (We'll use horses again for the example, but I'm not making a horse race. Heh, horse race. Comedy gold, that one.) may not have solid tails that would make sense to measure. This measurement is considered similar to height in measuring for size categories, though keep in mind that 5e doesn't have a hard limit on what makes each size category (There might be one, but I haven't seen it stated). Measuring weight is basically unchanged, though quadrupeds tend to be a little heavier than bipedal creatures of the same size.
Manipulating Objects: Assuming you're playing a sentient creature, you can still manipulate weapons, tools, and objects with your mouth or front limbs. However, if these front limbs wouldn't be able to hold items (Such as if their hooves, and not claws or hands), then even if the race is sentient you should not be able to wield and use them (Though you may still understand how they work if you're sentient). However, if your race is sentient AND has front limbs with digits, congratulations, you can use things like anyone else. However, without opposable thumbs, this is much more difficult unless the tool, weapon, or other item has been explicitly made to accommodate this difference. This doesn't necessarily ruin your skill with them in any way, but makes it take longer to perform any action with them. Any such use that takes a bonus action instead takes an action, and any that takes an action would instead take either your action and movement, OR you action and bonus action. You can use your reaction for the round to avoid this penalty once. However, unless otherwise stated, if you have starting equipment, ALL of it is made to accommodate this difference. Any weapons, tools, kits, if it's yours, it is built to be used by either your mouth or your specific "hands" (Claws, probably). The exceptions to this are obvious, things like money and the like won't be different, and your bags to store all your gubbins aren't custom-made to let you grab them easily. Any such equipment built to be used by you does NOT take longer than normal to use.
Examples: Some examples of Quadruped races will be displayed below when I finish this ruleset, as it only exists as part of a larger project I'm making about revamping the way dragons are appear in 5e. If you're wondering, that page is Dragons Reborn! (5e Variant Rule).