"We are listening to that cat."
Translation:My słuchamy tamtego kota.
Not only you don't need it, using it would deprive the sentence of any sense. In Polish you 'listen something/someone', not 'listen to'. Just like you hear something and not 'to something' (in Polish as well).
And this something/someone is in Genitive.
Hi, I thought tamta Kota for that Cat .When do you use tamta rather than tam tego.
"tamta" is feminine, and the basic word for "cat" (kot) is masculine.
"słuchać" (to listen to) takes Genitive, Genitive for "tamten kot" (that cat) is "tamtego kota".
"kotki" (from "kotka") is a female cat. It's on the list of accepted answers, although it isn't taught.
Duolingo usually doesn't seem to care about the difference between 'this' and 'that', but in this case, 'my słuchamy tego kota' was not accepted.
It's not that we don't care about the difference (for example, the main answer should always correspond exactly, this=ten and that=tamten), but the way those work in English and in Polish are just different. Yeah, 'tego' should have worked, added.