Let’s start with:
(1) Hunted for its horns, 95 percent of the population disappeared
This looks like a classic “dangling modifier”. We have a SPAR hunted for its horns (a Subjectless Predicative Adjunct Requiring a referent for the missing subject), but the adjunct doesn’t obey the Subject Rule (doesn’t pick up its referent from the subject of the main clause: (1) doesn’t in fact tell us that 95 percent of the population was hunted for its horns). (On the concepts and terminology, see the material in the Page on “Dangler postings”, especially the “as a SPAR” posting.)
But even without context, (1) is easily understood: 95 percent of the population is a metonymic stand-in for a population of X, and it’s X that was hunted for its horns. But that takes some interpretive work. However, when more discourse context is provided, this work is no longer needed, and I’d expect that readers wouldn’t even notice that (1) is technically a dangling modifier.