Since you didn't post any of your own thoughts on this image, my critique will be short and sweet...
This is an excellent black and white but it didn't score well because the photo doesn't meet the challenge in a standard way. People generally think of portraits as shots of 'people'. Better luck next time :)
Whilst I'm sure you'll be hammered for the lack of a human being, I like this shot very much personally. I wish you'd been able to find more contrast between the water and the hippo, though - but the clarity and the detail are excellent.
nice B&W image, some here at DPC don't like animals in a portrait challenge, I do however. way to carry the focus thru the entire length of the hippo's head.-7-