In general the default for cats and dogs is the male form, though it can be ambiguous between male and don’t know / don’t care.

For instance if you saw a random unidentified cat you could say you saw “un gat / gato / chat”, and it would be impossible to tell whether you were referring to a male cat or a cat of unknown gender (while if you used the female form it’d be unambiguous).

Romance languages really could use a neutral form, but “gat@”, “gat*”, or “gatx” just don’t work when you try to figure out how to say them out loud, and using the female form for neutral just moves the problem to the other side.

About 80% of orange cats are male; not as clear as one in three thousand for calicos, but stilll.

The problem is that what sounds good in German doesn’t necessarily sound good in other gendered languages (romance languages, for instance), so if you know both you need to know multiple mutually incompatible lists of arbitrarily gendered words.

Many romance languages have both; for instance, in Catalan “gos” / “gossa”, “gat” / “gata”, in Spanish, “perro” / “perra”, “gato” / “gata”, or in French “chien” / “chienne”, “chat” / “chatte”.