CHALLENGE 65

When the circus came to town a large crowd assembled to see the 'Grand Parade'. Firstly a beautiful white Horse galloped past followed by a large brown Hare and close behind an elegant Zebra. After a little gap came a big male Lion followed by a large Hippopotamus and not far behind, keeping it's distance from the Hippo that preceded it, was a white Goose. A Proboscis Monkey strolled along after the Goose and much later came a big Gorilla who slowly ambled down the road. Everybody looked in anticipation to see what animal would be next, can you guess what it was and why?