Does css hover work on mobile devices?

Sigh. It seems like no-one answering this question actually tried it on a real device. In many cases it does work. The first click acts as a hover.

Some more info here: http://designshack.net/articles/css/are-hover-events-extinct/

The :hover pseudo-class needs a pointing (graphical input) device, capable of distinguishing the actions pointing and selecting/activating. Usually on mobile devices with a touch interface you don't have the former, only the latter. Also some pen interfaces only allow activating, not pointing.

The :hover pseudo-class applies while the user designates an element (with some pointing device), but does not activate it. For example, a visual user agent could apply this pseudo-class when the cursor (mouse pointer) hovers over a box generated by the element. User agents not supporting interactive media do not have to support this pseudo-class. Some conforming user agents supporting interactive media may not be able to support this pseudo-class (e. g., a pen device).

—W3C: CSS 2.1: Selectors, dynamic pseudo-classes

So, to answer your question: It depends on the device but likely no. And don't rely on it. With touch-screen devices quickly gaining in popularity you'll lose the entirety of pointing-only events.