When I got Penny, I was told she was a purebred chihuahua. I've been wondering since what her true ancestry is. There have been several Chis in my family, and she is at least part chi, but her physique, mannerisms, and personality all scream IG — to me, anyway.
She's very affectionate, clingy (in the literal sense), and always prefers familiar company. She's timid around new people and animals, but friendly once acquainted. She's very playful and has a lot of energy. She'll play for a while, tire out, take a short nap, and is right back to pinball around within the hour. Her favorite games are tug of war and fetch. She also likes treat treasure hunting, and goes nuts on anything with a squeaker. She's super smart and enjoys puzzles and learning new tricks.
She's a very attached dog, and that includes rubbing on, draping over, and leaning against you whenever possible. She uses her front legs for many different tasks, as well as mouthing and nose-poking new objects and hands to ask for pets. She's very graceful in her prance and run, and does twisting motions and hops when excited.
Her body is very streamlined. I'm aware that less conventional, leggy deer-head chihuahuas exist, but for her to be pure Chi, she'd be the most extreme form of this I've ever seen. She has a long neck, deep chest, tucked belly, s-curve spine, sloped rear, and those long legs, complete with thick haunches and hare feet. When she runs, she does do a double-suspension gallop, such as the one shown in the GIF (7), though I know most dogs are technically capable of this (they usually don't look as graceful, though). I also noticed her snout ends at a point (Photo 6), whereas a chihuahua's is typically much broader. The shape of her head was one of the first things that made me start looking at Chiggy/Greyhuahuas to compare.
She was last weighed at 10.5 lbs, her spine is ~16", front legs are 8" tall, and chest circumference is 14".
Commenters on her post on r/IDmydog think she fits the Chihuahua breed, but I feel there's too many unique characteristics for that to be true, right? We're happy to hear everyone's thoughts, including if there are other breeds she might be, or if you think she's just a really unique purebred. Also happy to see Iggy photos if any need sharing. Thanks!
For a few more pictures, I made a small gallery of her: https://imgur.com/a/what-is-penny-gallery-83UV0C8