Really it is more complicated than that in English. Most definitely if the animal is a pet then the animal is referred to as he or she. There are more and more now referring to all animals as that when the gender is known (and sometimes when not).
For cars, boats/ships and a few other things (like countries and cities), they are often referred to as she (this despite women were not allowed on boats for centuries – at least as crew – with the idea it would be bad luck). Then of course there is Lady Luck, and Lady Justice, and Mother Nature.
Why not, He appears in the night?
When I put that, I was told the correct answer is, He appears during the night and I see no Portuguese equivalent for "during" in Ele aparece à noite. But all three, including He appears at night mean essentially the same thing, and none of them is an exact direct translation.