I believe animals do prefer organs over other parts first because they are more nutritious. Maybe a coyote ate his organs and was full but how could he lose to a coyote at a rest stop. What are the odds a coyote ate his organs and nothing else came across the rest of him. Although I am not familiar with this rest stop it sounds like it is infrequently traveled. What are the odds organ thiefs were driving in the desert by this rest stop. That leaves one conclusion. Chupacabra!