All of the animals in those photos had HUGE eyes and tiny bodies, giving out that "cute" and "adorable" appearance. That is a very powerful tool in advertising because no one can say NO to those little guys. I remember watching TV commercials about animal abuse, filled with images of animals whom you just feel sorry for, and most importantly, whom you can't say NO to. Soon after you'll find yourself donating loads of money to save the poor animals, I know I did.
Now, I wonder: will the "cute" effect work throughout different types of campaigns? We shall see.

Monkey!