The question that I posed in the title is a philosophical one because, judged against human artistic values, obviously the girl is beautiful and the Iguana is exceedingly ugly. But if the actions of humans and the actions of Iguanas were to be part of the evaluation, then the result might not be so clear.
This morning, for example, I turned off the news on CNN which was showing just another day in Iraq. There were bodies everywhere, terrible destruction...well, I'm sure that you've seen it yourself. I just couldn't stand to see yet again what humans are doing to each other every day in many places in the world. It made me feel sick!
Of course, what humans are doing to each other is not always so graphic. The slow starving of billions of people which occurs as a result of a grossly unfair economic system, one which enables a minority of people to accumulate vast wealth, does not make for news. That people are dying from preventable diseases because of lack of medicines or health information or condoms, or because of contaminated water or landmines or from brutal occupation, etc, "Well, it happens and we don't want to see that," well-off people say with a shrug and check their investment portfolios with a smile.
It could be argued that, if we judge humans (well most) by their actions, surely the Iguana which hurts nothing or no one (beyond securing its daily food) is beautiful and humans are indescribably ugly.