How do Japanese differentiate between "mouse" and "rat"?
When I type mouse or rat into Google Translate, they are both called "nezumi" so how do Japanese speakers refer to the specific animal?
First ... I recommend using a legitamate dictionary for looking up Japanese words, rather than relying on Google Translate. It is notoriously good at generating nonsense without warning.
That being said, it is correct in this instance. The word ネズミ is used for rats and mice. Rats are relatively uncommon in Japan (cockroaches are more common pests in big cities). Most of the time, if you say ネズミ, people will be thinking of a mouse. But ネズミ or 鼠 can be used for either one and no one will find it odd. If it is important to distinguish, you can use マウス or ラット. But under normal circumstances, you just use ネズミ.
I stayed months in Japan and only saw one rat - in Shibuya as well XD Seems to be the most popular rat-spot in Tokyo then.
There's an article on this website basically entitled "what is the difference between ラット (rat) and マウス (mausu)?" If you wanted to specify, you could say ラット and マウス, but the difference wouldn't really have any meaning to the average Japanese person. The article also cites the more scientific names ドブネズミ (dobunezumi) for rats and ハツカネズミ (hatsukanezumi) for mice.
For those going through the new tree, this same issue comes up with sentences talking about ハト (hato). Duolingo accepts both "dove" and "pigeon", as Japanese doesn't differentiate between the two. "Pigeons are a symbol of peace."
Mice are smaller, softer, with a delicate triangular snout and round ears. Rats are often larger and greasier with a more rounded snout and hunched back.