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Maevatiana’s PhD on humpback whale mother-calf interaction: Whale Done!

In continuing a long-standing collaboration between the Cétamada association (Madagascar, led by Anjara Saloma) and the Acoustic Communications team at the Paris-Saclay Institute of Neurosciences (France, led by Isabelle Charrier), Maevatiana Ratsimbazafindranahaka began his PhD thesis on humpback whale mother-calf interactions in 2020 at the Paris-Saclay University and the University of Antananarivo. Supervised by Isabelle Charrier, Aristide Andrianarimisa, Olivier Adam, and Chloé Huetz, the research aimed to delve into nursing, swimming, and vocal behaviors using innovative multi-sensor tag techniques.

Maevatiana successfully defended his these in November 2023, and presented the first detailed description of the nursing pattern in humpback whales, offering unprecedented insights into this critical life stage. His work also elucidated the early development of calf activities and the maternal support that is crucial for navigating underwater. Additionally, the thesis explored vocalizations, particularly calf social calls, identified as a means of acoustic contact during vertical separations and in initiating behaviors such as nursing.

The study, conducted in the Sainte Marie Channel, an important breeding area in the Southwestern Indian Ocean, provided significant contributions to understanding mother-calf interactions in humpback whales, shedding light on maternal care, the development of young baleen whales, and the use of acoustic signals for communication in an aquatic context. While the research necessitated close approaches to the whales for tagging, effort was made to minimize disturbances and ensure animal welfare. Over the years, the team has perfected exceptionally soft tagging approaches, dubbed with a touch of fun as ‘Peace and Love’ tagging, currently among the least invasive tagging methods ever implemented. The team hopes the findings will inform conservation efforts and stimulate further research. Four articles have now been published in peer-reviewed journals. 

The thesis is available online here, and excerpts of the tagging approaches can be viewed on YouTube.

Contributor: Maevatiana Ratsimbazafindranahaka