http://www.dailymail.co.uk/news/article-1190772/What-squeak-Daring-mouse-
whos-boss-scares-leopard-steals-lunch.html
You're right; it's ungrammatical -- at least for me, a native
speaker of American English. It should be either "Stealthy hunters,
leopards ..." or "A stealthy hunter, the leopard is known ... its
prey ..."
--
Jim Heckman