Not much is known about the Niffler. It is a bit of an obscure creature and we know very little about it which you can see right here
Nifflers are native to Britain and they are called Nifflers. That’s pretty much most of what we know. They also have an obsession for all things shiny which is one of the best parts about them (and of ‘Fantastic Beasts and Where To Find Them®’) they love to have gold around them and they stuff it in their fur to try hide it but Newt knows all of their tricks ;). The only other thing we know about them is that they are very adorable. End Of.