I would specifically argue that the word "response" is itself contextually inaccurate, in the sense that it triggers ambiguity as to whether the change in reproductive rates is _intentional_ or not. My headline removes that ambiguity.
But that wouldn’t be as catchy and as misleading/misunderstood as the original. Anyone reading that one will assume that elephants are purposefully being born without tusk, but it’s just a ratio consequence of tusked elephants dying early.