Marine Iguanas and hetero-specific comprehension

Abstract: Galapagos marine iguanas are capable of understanding the alarm call of native mockingbirds and then respond with anti-predator behaviour.
By being able to discriminate and recognize hetero-specific alarm calls, the animals are able to tap into an extra source of information thus bolstering predator awareness. However, this is normally attributed to species that live in close proximity with one another.
There is still a debate over whether this is a result of a learned response by associating the call with predators, or if it is an innate response to acoustical properties of the sound itself.
Aim: it was to investigate whether the iguanas were capable of recognizing the mockingbird calls since they don’t emit any vocalizations or alarm signals themselves. They would benefit since it would be a rapid transmission of information, while they normally rely on olfactory and visual information which would be slower to transmit.
Method: Recorded mockingbird songs and alarm calls and played them back to iguanas while observing behaviour
Results: the iguanas showed significantly more vigilance behaviour when the alarm calls were played rather than the song
Discussion: Multiple reasons could have caused for this to occur. It seems that the iguanas were more likely to respond during times when their body was at a lower temperature, therefore benefiting from the additional time to escape given their inability to move as quick as they could if it was midday.