Please view the images at full size if possible.
18 photos and 18 species to identify. Each image has at least one eye and one nostril visible. In this puzzle all the animals have something in common and there are no odd ones out. As usual, there are several easy identifications to help everyone to start. But some are quite hard, so you will probably need to find the common factor before you can solve them all and some research is likely to be necessary (I suggest starting with Wikipedia, but other sources may be useful too). Remember that a species often has several alternative names.Once you have all the names, the second challenge is to list your answers in rank order, explain how you have ranked them. Note that some species may be entitled to equal ranking.
I will be happy to look at PMs with possible answers, but I will not reveal any answers until New Years Day. So please do not post any solutions in this thread until after noon (UST/GMT) on Saturday January 1st, 2022.
Merry Christmas and Happy New Year to all ZooChatters.