I never trained my dog. He understands pointing and many many full sentences that I regularly use that is related to him. I never specifically trained him to do something, I just talk to him like a kid. When he understands something new and amazing, I must produce a reaction. He taps on shoulder and walks to towards somewhere when he wants me to do something for him; I never taught him that. Domesticated animals and non-domesticated ones have the ability to learn and use their brain just like us.
Elephants mentioned there in Africa which have not been trained, they can also figure things out just the same. They can connect action and reaction just like us. Elephants use their trunk for point naturally so they process human arms as a trunk and our reaction proves that their analysis is correct.