Animals are heterotrophic, which means they count on other organisms—crops and/or other animals—for their meals, as they can't synthesize their own individual food as vegetation do by way of photosynthesis. The fossil record of animals goes back about 600 million years to the Ediacaran period, or to some degree previously. https://jaspersvvsp.jasperwiki.com/6903674/facts_about_animal_porn_revealed