Two of the zoo's caiman lizards were swimming in their pool, which occupies about 70% of the floor area of their exhibit. I think they may have been expecting food, and they were continually tasting the walls and the water with their tongues. The male suddenly grabbed the rear right foot of the female and held on for several minutes. She struggled and tried to bite him back, but could not do so. He hung on, but did not bite down or chew on her foot. When he finally released her, she swam away immediately and hid, but I could see clearly that she was unharmed; her foot was unmarked and there was no blood. Perhaps the male had tasted snail slime near her foot and was hoping for a meal.