10/22 -- Peña tweeted an apology later Sunday night, explaining that he was 12 years old when he first started using social media and was "very impressionable and was seeking attention."

He states in his apology that he has grown and matured a lot since those tweets, and hopes that everyone close to him knows he has "evolved as a human being." He explains, "I lead with love. I was a child and am now a man asking you to accept the apology of a young boy."

Viral sensation and self-proclaimed deer whisperer, "Brother Nature," started trending this weekend for all the wrong reasons -- old and incredibly vile tweets ... which invoked names like Jay-Z and Chris Brown.

20-year-old Kelvin Peña quickly turned his Twitter account to private Sunday, after people started re-posting screenshots of his old tweets from 2011 and 2012 ... many of which were racist, sexist and anti-Semitic. It's unclear what might've sparked the deep Twitter dive.

Nonetheless, what was revealed was quite disturbing. One such tweet said "Jay Z look like a monkey." Another one said ... "when I grow up I wanna be like Chris Brown. So if my girlfriend tried to look through my phone while driving I can choke and punch her :D".

There's a lot more that are even more disgusting -- tweets that say things like ... "HEIL HITLER" ... "Wanna hear a joke? Women's rights" and "TL stopped loading .. too many coons on my TL that's why f***." FWIW ... dude claims to be Dominican and Puerto Rican.

Peña first garnered attention (and views) back in 2016 with a viral video called "Money and the deer squad" which featured a deer he named Canela. He went on to put out more videos of himself interacting with Canela and other animals he encountered in "the wild" ... and eventually dubbed himself Brother Nature.

As we've seen lately with these viral types ... nothing stays buried for long. We reached out to Brother Nature's camp for comment ... so far, no word back.