Why is it that in fiction, female reptilian humanoids are smaller than the males or, at best, about the same size? According to actual reptiles, they should probably be either the same size or larger — due to the mechanics of mating in reptiles, it's rare for females to be smaller. Actually, this applies to other types turned into anthropomorphic animals, not just reptiles, but that's where I notice it the most.
Most likely as a function of the same rules that make them humanoid. A lot of Petting Zoo People have traits their animal species would suggest they shouldn't, like bipedal movement, opposable thumbs, two breasts, etc. You don't really need to start worrying until reptiles start wearing that last pair.
Snakes and some turtles have bigger females. Lizards and crocs generally have much larger males.
We're used to mammals, where the male is larger far more often, including in the case of humans ourselves. We therefore expect this of any species, assuming we (like many series creators) don't know the facts.
How come nobody gives a gargoyle the ability to spit water at a long range? I mean, it's where their names come from, for pete's sake! Why don't people give them a 'water spout' spitting technique?
This Troper did! Too bad nothing's been published outside of deviantART..
... Wow, that is an awesome idea. Don't worry, I'll use it!
Is there some kind of sliding scale for animal evil? Basically, the uglier ones tend to get evil fictional counterparts while the cute ones are usually portrayed as nice. Repitles and amphibians are kinda in the middle since opinions vary as to how cute they are.
A lot of reptiles (not all, but enough for a memorable impression) move slowly, get angry easily, are not too social, don't express emotions much, make grunting and hissing sounds, dislike attention, have rough wrinkly skin, and attack humans. To humans, they're much like that grumpy old man who yells at kids to get off his lawn. (This is the same reason why birds, despite being a sort of reptile, tend to be portrayed as good: They display a lot of behavior humans consider socially positive.) Turtles are exempt because they like human attention; geckos are exempt because they have tight babylike skin, are small, have large curious eyes, and move fast; chameleons are sometimes exempt because they have many unusual characteristics and are friendly to people; and to some extent, some dragons are exempt because they're mythical and majestic.
Where is the main page for this JBM? I mean, yeah, I am totally against the Reptiles Are Abhorrent trope, like a lot, but there is no Reptilian Humanoid Trope. I kinda want one, though... [[supersecretspoiler: Yes, I know I shouldn't be talking in first person, but still-]]