We don't know the backstory on this but we can basically make it up, it doesn't take a genius.
A sloth was trying to cross a heavily - trafficked highway, but hello. It's a sloth. So of course, it's slower than slow.
An angel of a man decided to get out of his car and help the sloth, not only to cross the street, but he lifted him ever so gently and placed him in a tree, far away from the road. He then kept holding on to him to make sure that the sloth had a good grip.
The sloth then turned around, smiled, and WAVED like it was saying 'thank you' and MY HEART IS BURSTING!