Alligators signal size by bellowing

Alligators signal size by bellowing

From our journal article: Reber, S. A., Janisch, J., Torregrosa, K., Darlington, J., Vliet, K. A., & Fitch, W. T. (2017). Formants provide honest acoustic cues to body size in American alligators. Scientific Reports, 7(1816), 1–11. https://doi.org/10.1038/s41598-017-01948-1

By Sience Daily

“In alligators and other crocodilian species, being bigger than your conspecifics can have decisive benefits: Females only accept males larger than themselves as mates and larger alligators are much more likely to win territorial fights. However, direct physical confrontations can lead to lethal injuries so it would be advantageous if fights could be avoided by individuals reliably signalling their body size to potential mates and rivals early on. One way to achieve this is by “honest” acoustic cues to body size in vocalizations. A team around Tecumseh Fitch at the Department of Cognitive Biology at the University of Vienna has now identified cues to body size in calls of American alligators, which is the first finding of this kind in reptiles.”
  • These bellows act as cues to signal their size to rivals and potential mates
  • They can help to avoid direct physical confrontations during territorial fights
  • They produce the bellows year round, but most frequently during mating season
  • Researchers found that a specific type of sound frequency in their bellows, called resonance frequencies, act as an almost perfect predictor of their size
  • They also found that only male alligators produce what’s known as a ‘water dance’ – when water droplets sprinkle over their backs directly before the bellow

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