Our oceans today have become home to a great deal of noise.  This noise is attributed to many things, such as human recreation, shipping vessels, oil drilling, military operations, and many others.  This addition of extra noise in the oceans creates a need for marine life to compensate.  Vocal compensation strategies include increasing the amplitude (volume), duration, and/or repetition rate of one’s acoustic signals to help reduce the probability of masking from environmental sounds.  Although accumulating evidence from recent research illustrates that several marine mammal species readily modify the parameters of their acoustic signals to compensate for masking noise, potential energetic costs of such compensation behavior are unknown.  To our knowledge, there is no empirical data on the metabolic costs of sound production of any marine mammal species.  Given that changes in vocal behavior in response to masking noise has been documented in several species, assessing the biological significance of these effects is paramount, but also very difficult given the life histories of marine mammals.

This project is designed to build upon previously trained behaviors.  The animals rest while we measure their metabolic rate and are asked to produce various vocalizations for varying amounts of time.  The amount of oxygen consumed while they perform these vocalizations will help researchers begin to deduce how much energy (calories) is required to produce these sounds.   Additionally, animals will be trained to produce additional types of vocalizations, such as echolocation clicks, as well as perform these vocalizations at different volume levels and for various durations.

Data collected from this study will provide valuable information about sound production costs in odontocetes (toothed whales and dolphins) including costs of modifying acoustic signals in response to anthropogenic sound exposure.  This has direct implications to ocean conservation because if there are significant costs to sound production for these animals, and they are being required to produce sound louder and longer to overcome the amount of noise we put into the ocean, then this could lead to detrimental impacts on animal’s energy balances.  If this balance is disrupted, this can affect species survival as well as reproductive outcomes.