Why do some deer have horns while others not?

It's not horns that deer have, but antlers. And the answer to why some deer have antlers while others don't lies in their sex and species.

Here's a breakdown:

* Sex: In most deer species, only male deer (bucks) grow antlers. Antlers are a secondary sexual characteristic, meaning they're used to attract mates and compete with other males for dominance.

* Species: While most deer species have antlers, some species, like the reindeer, have antlers in both males and females. Reindeer females use their antlers to dig through snow for food during the winter.

Here's how antlers grow:

* Antlers are made of bone, not keratin like horns.

* They grow from bony projections called pedicles on the deer's skull.

* They are covered in a velvety skin called velvet that provides blood supply and nutrients to the growing antlers.

* The antlers are shed and regrown annually, usually in the late fall or winter.

So, in summary:

* Male deer grow antlers for mating and competition.

* Female deer usually do not grow antlers, except for reindeer.

* Antlers are made of bone, shed annually, and grow from pedicles on the skull.