Quote Originally Posted by Throbert McGee View Post
Antonio, пёс is used when you want to particularly emphasize that your dog is "a boy"!

The word собака is grammatically feminine, but can be used either:
(a) about a female dog
or
(b) about a dog whose gender/sex is not known to the speaker.

The word сука means "a definitely female dog" (and cannot be used for a dog of unknown gender) -- but, just like the English bitch, nowadays it is "used politely only by professional dog-breeders."
The word соба́ка is general. A dog can be called собака even if it’s known it is male.

The word пёс can sometimes be used to refer to a dog whose sex is not known (more rarely than собака though).

There’ş also a word кобе́ль — ‘a male dog’. Like су́ка, it is used mostly by dog-breeders and can be used as an offensive word too (‘tomcat’ (?), ‘sleazebag’(?), don’t know how to say it in English).
It’s the word кобель that means a definitely male dog.

A similar thing is with horses.
Both ло́шадь (grammatically feminine) and конь (grammatically masculine) can be used for horses of both sex.
Ло́шадь is more general, while конь is a bit rarer.
If you want to tell about a horse’s sex, you can use words кобы́ла ‘female horse’, ‘mare’; жеребе́ц ‘male horse’, ‘stallion’; ме́рин ‘castrated male horse’, ‘gelding’.