BSD sleep

Hi. Is there no built-in way of making "sleep" sleep in increments 
of minutes, hours, etc? The GNU "sleep" can be invoked like "sleep 
1h" for an hour. The FreeBSD one's manpage leads me to believe we 
can only use seconds, which is kind of annoying. Is there an 
undocmented or missing feature here? Seems really trivial to 
implement.

~ $ sleep 1h
usage: sleep seconds