Please do your homework before teaching others English to avoid wasting other people's time and public resource.

There are millions and millions examples in which American writers used 'have N legs",  I just give a few here.

All dogs have 4 legs.
- Psychology 240: Statistics 1 Lectures: Chapter 8

Spiders (order Araneae) are air-breathing arthropods that have eight legs

http://en.wikipedia.org/wiki/Spider

Illuminations: Spiders Have 8 Legs

How Many Legs does a Spider Have | Reference Answers

Evolutionary history helps explain why humans have two legs ...
 - articles.washingtonpost.com › Collections‎

Why do humans have two legs and not four - WikiAnswers