Size does matter: crocodile mothers react more to the voice of smaller offspring.
Parental care is widespread in Archosaurs (birds, crocodilians, dinosaurs and pterosaurs), and this group provides a useful model for the evolution of parent-offspring interactions. While offspring signalling has been well-studied in birds, the modulation of parental care in crocodilians remains an open question. Here we show that acoustic communication has a key role in the dynamics of crocodilian' mother-offspring relationships. We found embedded information about the emitter's size in juvenile calls of several species, and experimentally demonstrated that Nile crocodile mothers breeding in the wild are less receptive to the calls of larger juveniles. Using synthetized sounds, we further showed that female' reaction depends on call pitch, an important cue bearing size information. Changes in acoustic interactions may thus go with the break of maternal care as well as dispersal of juvenile crocodilians. This process could have characterized other archosaurs displaying rapid early growth such as dinosaurs and pterosaurs.
Equipe Neuro-Ethologie Sensorielle, ENES/Neuro-PSI, CNRS UMR9197, Université de Lyon/Saint-Etienne, France.
T
T
Chabert
Equipe Neuro-Ethologie Sensorielle, ENES/Neuro-PSI, CNRS UMR9197, Université de Lyon/Saint-Etienne, France.
A
A
Colin
Equipe Communications Acoustiques, Neuro-PSI, CNRS UMR9197, Université Paris-Sud, France.|Centre National de la Recherche Scientifique, UMR 9197, Orsay, France.
T
T
Aubin
Okavango Crocodile Monitoring Programme, Maun, Botswana.
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V
Shacks
Okavango Crocodile Monitoring Programme, Maun, Botswana.
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SL
Bourquin
Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, Louisiana, USA.
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RM
Elsey
Fundo Pecuario Masaguaral, Francisco de Miranda, Estado de Guárico, Venezuela.
J G
JG
Acosta
Equipe Neuro-Ethologie Sensorielle, ENES/Neuro-PSI, CNRS UMR9197, Université de Lyon/Saint-Etienne, France.|Department of Psychology, Hunter College, City University of New York, USA.
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N
Mathevon
D000489:Alligators and Crocodiles / Q000502:physiology*; D000818:Animals; D049628:Body Size; D005260:Female