Nursing Behavior in Sperm Whales (Physeter macrocephalus)

• Published in: Animal Behavior and Cognition
• Main Authors: Sarano, François, Sarano, Véronique, Tonietto, Modan-Lou, Yernaux, Adrien, Jung, Jean-Luc, Arribart, Marion, Girardet, Justine, Preud'Homme, Axel, Heuzey, René, Delfour, Fabienne, Glotin, Hervé, Charrier, Isabelle, Adam, Olivier
• Other Authors: Institut de Systématique, Evolution, Biodiversité (ISYEB ), Muséum national d'Histoire naturelle (MNHN)-École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL), DYNamiques de l’Information (DYNI), Laboratoire d'Informatique et des Systèmes (LIS) (Marseille, Toulon) (LIS), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Institut des Neurosciences Paris-Saclay (NeuroPSI), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut Jean Le Rond d'Alembert (DALEMBERT), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: Sperm whale; Nursing; Allonursing; Suckling; Underwater observations; [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology; [SDV.NEU.SC]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]/Cognitive Sciences; Physeter macrocephalus
• Online Access: https://hal.science/hal-04207557; https://hal.science/hal-04207557/document; https://hal.science/hal-04207557/file/Nursing-Behavior-Sperm-Whales-Sarano_et_al_ABC_10%282%29.pdf; https://doi.org/10.26451/abc.10.02.02.2023

International audience In mammals, lactation is the universal behavior of feeding offspring and has a fundamental nutritional and social value with offspring staying near their mothers. In order to obtain milk, terrestrial mammal offspring squeeze the breast of lactating females and suckle the nipples with their tongues. In the specific case of cetacean species, it was reported that lactating females intentionally eject milk from their mammary slit into the calves’ mouths. Nursing behavior in sperm whales has already been broadly described, but the results of our current study, based on 127 underwater videos, recording over 7 years and displaying explicit nursing behavior, bring a higher level of understanding. We first showed that sperm whale calves are proactive in getting milk. We were then able to illustrate and describe with a high level of precision their suckling behavior: firstly, the calf bumps its head onto the female’s genital area to signal the mother its willingness to suckle; secondly, the calf introduces its lower jawbone into the genital slit, this action makes the nipple pop up from its slit; thirdly, the calf squeezes the nipple with its tongue against the hard palate and suckles; fourthly, the calf removes its jawbone from the female and swims off. Moreover, our underwater visual observations provided the first direct evidence for allosuckling in sperm whales, a situation during which a calf obtains milk from an adult female who is not its mother.