Learn Hardcore Russian: У оленя красивые рога, но коза подошла к нам ближе и совсем не боялась. - The deer has beautiful horns, but the goat came closer to us and was not afraid at all.

Breakdown of У оленя красивые рога, но коза подошла к нам ближе и совсем не боялась.

Why does the sentence use У оленя instead of something like олень имеет for the deer has?

Russian very often expresses possession with the pattern:

у + possessor in the genitive + есть / implied there is

So У оленя красивые рога literally feels like:

At the deer, there are beautiful antlers.

This is the normal, natural way to say the deer has beautiful antlers.

A few key points:

у = by / at
оленя is the genitive singular of олень
In the present tense, есть is often omitted when it is just giving simple existence/possession

So:

Using иметь is possible in Russian, but it is often less natural in everyday speech for ordinary possession.

Why is it оленя and not олень?