“And to all the beasts of the earth and all the birds in the sky and all the creatures that move along the ground–everything that has the breath of life in it–I give every green plant for food.” And it was so” (Genesis 1:30).
Animals were created herbivores (Gen 1:30). Humans corrupted them through selective breeding for profit (Gen 30:37-43). And by neglecting our divinely ordained responsibility of earthly stewardship (Gen 2:15), we also destroyed the habitat God created for them and their natural food sources they were designed to eat.
When we have a change of attitude and return to God and live by love instead of fear and selfishness, through humanity (Matthew 18:3) God will restore the earth to the way it was before we corrupted and destroyed it (2 Chronicles 7:14). Then all the prophecies about animals lying down safely without fear will come true (Hosea 2:18, Isaiah 11:6-9, Revelation 21:4, etc).