"Tom is my cat."
Translation:Том — мой кот.
I'm confused. Why exactly can't I say "Том — моя кошка"? I was under the impression that though "кошка" was grammatically feminine, the word could refer to a cat of any sex (just like how in French, the word "personne", meaning "person," though grammatically feminine, can refer to a person of any sex).
Why is my reasoning incorrect?
The first names for a female cat that come into my mind are Мурка and Муся/Муська. For male cats, Барсик, Вася/Васька, and Мурзик are very common.
My husband had a tomcat named Тимоха (a form of Tim) when he was a boy. So, after we decided to name our son Тимофей (Timofey), the first thing his father asked was: What, after our cat? It is a family joke now, that our Tim was named after a cat :-)
There are tips and notes for every lesson, but they are only visible in the web app. https://www.duolingo.com/skill/ru/Possessive-Modifiers-1
Tips and notes
POSSESSIVE ENEMY MINE
There isn't much to say about words like "my" or "your" in Russian.
his/her/their do not change: его́, её, их(and they don't get an initial Н after prepositions!)
my/your/our roughly follow an adjectival pattern, i.e. they copy the gender and the case of the noun they describe. Just like этот:
Unlike English, no distinction is made between my and mine, her and hers etc.
Pronunciation: in «его», as well as in adjective endings and "сегодня" the letter Г is pronounced В. It is a historical spelling.
Nouns in Russian belong to one of three genders: feminine, masculine or neuter. If a noun means a person of a certain gender, use that one. For all other nouns look at the end of the word:
(TABLE) ENDING IN NOM; GENDER; EXAMPLES
-а/-я ; feminine ; ма́ма, земля́, Росси́я, маши́на
consonant ; masculine ; сок, ма́льчик, чай, интерне́т, апельси́н
-о/-е ; neuter ; окно́, яйцо́, мо́ре
-ь ; feminine or masculine - consult a dictionary ; ло́шадь, ночь, мать, любо́вь / день, конь, медве́дь, учи́тель
IF THERE'S A SOFT SIGN, IT ISN'T POSSIBLE TO PREDICT THE GENDER, AT LEAST, NOT ACCURATELY. HOWEVER, ABOUT 65-70% OF THE MOST USED NOUNS THAT END IN -Ь ARE FEMININE. ALSO, YOU CAN LEARN THE COMMON SUFFIXES ENDING IN A SOFT SIGN THAT PRODUCE A WORD OF A PREDICTABLE GENDER. THEY ARE:
-ость/-есть, -знь → feminine
-тель, -арь, -ырь → masculine
ALL NOUNS WITH -ЧЬ, ЩЬ, -ШЬ, -ЖЬ AT THE END ARE FEMININE. THE CONVENTION IS TO SPELL FEMININE NOUNS WITH A SOFT SIGN AND MASCULINE ONES WITHOUT ONE: НОЖ, ЛУЧ, МУЖ, ДУШ. IT DOESN'T AFFECT PRONUNCIATION, ANYWAY.
Because that literally means "Tom 'exists' my cat." You need to put Tom's name in the genitive case to indicate ownership of something and precede it with у to refer to the space around Tom. Есть is only used for simple statements like this are primarily indicating whether something actually exists or not. If you were saying "he has a lot of blue cars" you would only use У Тома много синих автомобилей. In this 2nd sentence, the focus is on "a lot of" and "blue" cars. The fact that they exist is presupposed and obvious because they are being described and the issue of whether they exist or not is not the main focus; the number and color of the cars is the focus, hence no need for есть.