Culture, Biology, and Dietary Headcanons

Houyhnhnms:

Equus captungula sapiens

Ponies have both estrus and menstrual cycles.

They’re also venomous; their venom is made of theobromine and phazon and is injected through their fangs or retractable spurs on the hooves
(unlike the platypus, females have the spurs too). Harkens back to the multicolored reason.

On that note, the teeth. They have the same incisors and (pre)molars as normal horses, but the canines differ. For the front canines, only the top two exist, and are extended into long fangs that often stick out of the mouth. The back canines (wolf teeth) always exist. The gap where the bridle goes doesn’t exist, as it’s where the muzzle was shortened (No evolutionary advantage, really)

Ponies are tetrachromats, they have the same two cones that normal horses do, as well as an additional two, sitting more towards the ends of the visible light spectrum, allowing limited access to near-infrared and a decent ultraviolet. Though they can’t distinguish green and yellow too well and have limited ability to see orange and red.

Peak absorbency at 370nm (UV), 445nm, 508nm and 666nm (For reference, humans are at ~445nm, ~508nm and ~565nm)

Puppysmiles has an amaranthine (UV) coat and pink (IR) eyes

Ponies have 69 chromosomes

All ponies have
Hooves- Obviously
Cloven front hooves- Earthsong paws/Tiny Sapient Ungulates
Non-cloven back hooves- Heart shaped (Taurson) with thick hoof-bean frogs (Brainiac)
Chest fluff- Thick and fluffy
Fangs- Upper front canines
Feather ruffles- These occur on the fetlocks. Are made of iron and ferromagnetic, and can be used to sense magnetic fields. Feel kind of like tinsel (specifically the shredded silver variety)
Large eyes- The largest of any animal relative to overall size. Have extrasensory organs on the sclera
Dewclaws- Inject venom
Teats- Multiple to better feed the more energy-hungry foal

Can stand bipedal easily, but have difficulty walking on two legs (Some manage, such as Lyra and Rampage)

Ponies are actually hard for most predators to eat fresh. They produce a chemical that slows down acidic breakdown and can give anything that eats them serious indigestion.
Only their long ago predators, the griffons, have developed an enzyme that counteracts it, while more powerful ones must rely on the rate of their metabolism to avoid problems.
More intelligent predators have learned to let decomposition set in before feasting, when the chemical has had time to drain from the body.
As infamous brigand Kris the Cook put it: “Should let hang in a bag and ripen for two days.”

Earth ponies have sanguinic jamming pads on their hooves, pegasi have cloud hooks, unicorns have small crystals, and alicorns have all three.

The “fingers” footprints are spade, diamond, club from inside to out. Hind hooves are heart shaped, the points facing forward.

An oil-producing preening gland exists in the back of the throat, as such, they can spit oil

Hair (as opposed to fur) present on mane, tail, chest, and on and between the elbows and stifles. Sometimes matches the mane/tail in some individuals, particularly the armpit and pubic hairs

Fur has properties akin to steel wool. Hair, on the other hand, is highly fluffy. Cutie marks are effectively a steel brush

Wings are actually part of the lymphatic system.

The cutie mark glows under UV light when the pony’s special talent is being expressed

Gestation is 10 months. Foals are born helpless, unlike wild and domestic horses. Pegasi are born with their wings under a thin, transparent layer of skin. Unicorn horns in newborns are a simple lump of ferozium and alicornite

Horns are actually two horns with one wrapped around the other clockwise (Counter-clockwise in Dinky’s case), containing a ferozium core and a nerve cluster. When lit up, tiny pores secrete liquid phazon

Descended from Przewalski’s horse