It's not just animals bodies that we are changing, it's their behaviour too. We are so ubiquitous that other species are increasingly coming into contact and conflict with us. To continue to exist and live alongside us, or avoid us, they are being forced to adapt their behaviour.
Nature is amazing, and animals can and do adapt to changes.
However, many cannot adapt, or cannot adapt quickly enough as we take over their land and their lives. Our growing population and our actions are causing other species to either adapt or die. For too many, the latter is the only option.