VIM syntax highlighting works in MacVim but not vi on command line?

When I edit a file with mvim (Installed via MacVim) I see syntax highlighting in colour on a large range of files. However when I edit with the built in vi there is never syntax highlighting. Is there something you need to do?

Colour does work with other command line commands, i.e. git, ls etc... The problem is only with vi

Im on latest OS X 10.11.5:

> vi -version
VIM - Vi IMproved 7.3 (2010 Aug 15, compiled Apr  5 2016 14:53:37)

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