A 70mm lens is the preferred "portrait lens", which seem counter intuitive. But if you think about it, a portrait is usually head and shoulders, think school pictures, without the camera being right in the subjects face. Try it with your friend, seeing how close you have to be to get the same school picture with the 50mm and 70mm.
Now if you apply that same reasoning, you can take a sort of fearless squirrel, or cowardly flower, filling the frame without being on top of it. Then you can take same wider shots as the 50mm, without walking way over there, 'cause walking is so 20th century, plus really hard walking up a tree trunk.
