This is the worst thing David Attenborough says he's seen in his 60-year career as a naturalist

This week Sir David Attenborough, aka the British Morgan Freeman, fielded a Reddit AMA about his 60-year career as a naturalist and documentary filmmaker.

Sir David has created and amiably narrated countless BBC nature programs, including the Life and Planet Earth series. He is best known for the quality and scope of his work — covering wildlife and ecosystems all over the globe — as well as for his hushed, reverential whisper. His voiceover could even lend dignity to a turtle humping a shoe, as this magnificent video proves:

During Wednesday's Q & A on social news site Reddit, in which many Redditors pretended he was speaking out loud, Sir David touched on career highlights, personal favorites (sleeping, chocolate biscuits), and reflections on the natural world:

Most disturbing/upsetting moment? "Seeing chimpanzees kill monkeys. They do this to eat them. They chase them, set an ambush, catch them, and tear them apart."

Scariest moment working with birds? "Being charged by a cassowary." [As Redditors noted, this clawed, flightless bird is the "closest living thing to a Velociraptor" and best described as a "war ostrich." Fun fact: It also has its own subreddit: r/cassowary.]

Most compelling support for evolution? "The fossil record absolutely speaks for itself. That's all the evidence you need."

Thoughts on whether we're entering a "sixth mass extinction"? "Yes, I'm afraid we are. It's not possible to reverse the damage we've done. We are undoubtedly exterminating species at a speed which has never been known before."

One message for the current generation? "Cherish the natural world, because you're a part of it and you depend on it."

Sir David also offered this humbling observation: "I hope there is nothing I won't see again, the beauty of the natural world is that it repeats itself."

Then, because it's Reddit, a freestyle rap homage ensued, improvised by Sir David's fans:

David is so hood
Brought up in the Atten borough
Atten borough born and raised
In the jungles is where I spend most of my days
trekking out, waxwing, heron all cool
and shooting some new film, time-lapse of their stool
When a couple a flies, who were up to no good
Started eating doodie off a plank of wood
I tried one little bite and my crew just stared
And sent me to the Arctic to film polar bears

Sir David released his latest film Natural History Museum Alive (which has its own app!) on New Year's Day in the UK. Check out his full AMA here, plus this amazing video of his recent 3D work prepared just for Reddit. Sir David F. Attenborough, everyone. You can hear his mic drop from London.