This prophecy is actually a subset of the 4th seal judgment, the pale horse.  It speaks of a time when the wild animals in our world will entirely lose the fear of mankind that they have now and will begin attacking and killing people by the thousands or more.  It'll be like Jaws, Hitchcock's "The Birds", and every other animal attack movie all wrapped up into one.  I've put this out on its own apart from, but still attached to the 4th seal judgment as both a means to track this branch of the prophecy, and its growing pre-tribulation activity around the world.  And yes, while I realize the 4th seal isn't open yet, nothing says that the events it portrays can't have a smaller, earlier, pre-trib fulfillment.

Edit (2020-02-05): I'm seeing a bit of a pause in the fulfillment of this prophecy, so its status is being set to "partial fulfillment" until more significant forward motion on its fulfillment begins to happen again.