Taking animal shots is very time consuming, a lot of waiting for things to happen and a lot of wasted shots taken to anticipate upcoming events which turned out to be nothing. So hang in there, study their behaviour while waiting for the good light and fun opportunities to present themselves
In the zoo the extra challenge is to make the shot look like its been shot in the wild, unless you want to tell a sad story of the poor animal locked up behind bars for life. In that regard the lion image doesn't work for me as the wall in the background puts the lion in the zoo but the butterfly image could have taken everywhere, well done.
Elephants are a difficult topic because they are a very big grey blob with little pigmy eyes, haven't succeeded myself in capturing them properly in the zoo. I like your image though but would like to see it in black and white as the eye is attracted to the brightest or most colourful spot in an image and in this case that is the background and not the cute couple. In B&W you equalise the colour pallet and with proper sharpening and added contrast only applied to the main subjects they should pop out of your screen and become the main focus point.
