Animals who try to sound 'bigger' are good at learning sounds

JULY 7, 2020

by Max Planck Society

Some animals fake their body size by sounding bigger than they actually are. Maxime Garcia from the University of Zurich and Andrea Ravignani from the Max Planck Institute for Psycholinguistics studied 164 different mammals and found that animals that lower their voices to sound bigger are often skilled vocalists. Both strategies—sounding bigger and learning sounds—are likely driven by sexual selection, and may play a role in explaining the origins of human speech evolution.

"If you saw a chihuahua barking as deep as a rottweiler, you would definitely be surprised," says Andrea Ravignani, a researcher at the MPI and the Dutch Sealcentre Pieterburen. Body size influences the frequency of the sounds animals produce, but many animals found ways to sound smaller or bigger than expected.

"Nature is full of animals like squeaky rottweilers and tenor chihuahuas," explains Ravignani. Some animals fake their size by developing larger vocal organs that lower their sound, which makes them sound larger than you would expect. Other animals are good at controlling the sounds they produce. Such strategies (called dishonest signalling by biologists) could be driven by sexual selection, as males with larger body size or superior singing skills (hitting very high or low notes) attract more females (or vice versa).

Garcia and Ravignani wondered whether some animals may have learned to make new sounds as a strategy to attract mates. Few animal species are capable of vocal learning, among them, mammals such as seals, dolphins, bats and elephants. For instance, seals can imitate sounds, and some seals copy call types of successfully breeding individuals. Would animals who often 'fake' their body size also be the ones capable of learning new sounds?

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