Iguana the world’s only sea-feeding lizard has come up with a surprise for researchers. Scientists have noted that Iguanas recognizes and utilizes the alarm call of the Galapagos Mockingbird. This is the first instance of a non-vocal species utilizing the calls of another species. Galapagos Hawk prey on both Iguanas and Mocking Bird. Scientists are trying to ascertain whether the eavesdropping on mockingbirds is a learned behavior or ingrained.
For more details refer to Maren N. Vitousek, James S. Adelman, Nathan C. Gregory, and James J. H. St Clair (2007).
Biology Letters, Heterospecific alarm call recognition in a non-vocal reptile.