Tourists scoping out Iguana iguana from boats in Latin America may be treated to the critters bobbing their heads furiously. This odd movement isn’t the reptiles nodding along to an unheard reggaeton beat — it may actually be a sign of distress, according to a recent study published in the journal Biotropica.
“One of the functions of head bobbing can be to communicate danger to [other iguanas],” the researchers write. “Boat activity could provoke anti-predator behavior, due to their large presence and loud noise, which could be perceived as threatening.”
Todd Lewis, an ecologist at the University of the West of England in Bristol and co-author of the paper, worked at the Caño Palma Biological Station in Costa Rica for several years. There, he saw boat traffic steadily increase to satisfy tourists eager to spot iguanas and other species. “When we used to get two or three boats sort of clustering,” he says, “I started to notice that animals would disappear from the riparian edge.”
