#but i absolutely adore going in-depth into the mersupial lore

[salparadiselost]

Has How to Train Your Mers Dickie ever been mistaken as a mermaid by new guests at the aquarium because of his long hair and pretty face?

Like as female? I would guess so yes! Though his name is Dick which is very... male.

But! Male and females don't have a ton of species dimorphism in the HTTYM-verse.

Males are larger, mainly to provide better protection for their young and because their tails need to accommodate a pouch. Females are smaller, slimmer and often have a lot for scarring from fights. Females are also almost always living on their own, while males tend to form a pod. Male mer tails tend to be wider and they have the pouch seam, whereas female mer tails are slimmer. However, the difference between their tails isn't so great that untrained eyes can tell. Because female mers are often aggressive towards pups that aren't their own and may try to kill the pup a male is pouching to make room for her own, male mers have an incentive to hide their pups inside their pouches and keep it looking as normal as possible.

Female mers also do not have any form of breasts like human females do. Neither males or females have nipples visible on their chests. Males have a single nipple inside of their pouch, which the mer pup will suckle on until they are weaned. This is also one of the reasons that twins are extremely rare for mers. There's only one pouch and one nipple, so dad really only has room for one. In the rare instances were twins do occur, the dad would need to transfer the pup over to another male with an empty pouch who is willing to pouch them.

So! Although there are physical differences between male and female Mers, they tend to be pretty nuanced or not visible to the naked eye. This would increase the chance that Dick gets called a girl lol