I think certain wyverns can be pretty small (A species that grows to about only 2 feet tall)
Wyverns are traditionally the largest species from what I've read, they grow to be about 40 feet long whereas a common european dragon would top out at about 25
though it's been a while since I checked my books so the exact figures might be a little bit off
I bet it hates taking jogs
surprisingly enough they're not THAT slow for their size
but yeah they basically can't do much more than a waddle, its adorable
my feral 'sona is part knucker