In an unprecedented observation, researchers captured the birth of a sperm whale calf, documenting how 11 whales from two normally separate family groups coordinated closely to support the newborn for hours after its arrival. These findings offer quantitative evidence of direct communal caregiving in cetaceans and suggest that short-term, highly coordinated cooperation during critical moments like birth may play a foundational role in maintaining the complex social structures seen in sperm whale societies. The evolution of cooperation remains a fundamental question in biology, particularly among highly social, long-lived mammals such as toothed whales. Species like sperm whales exhibit remarkably intricate social systems, in which stable, matrilineal family units cooperate in activities such as foraging and communal caregiving. Birth represents a critical and high-risk moment for the animals, as whale calves require immediate support to survive, making it a uniquely revealing context for understanding cooperative behavior. However, studying these deep-diving creatures in the open ocean represents a significant challenge and direct observations of sperm whale births are exceedingly rare. As a result, the cooperative behavior in sperm whale births has long remained a mystery.
Here, Alaa Maalouf and colleagues present a detailed, high-resolution analysis of a sperm whale birth by integrating drone video footage, machine learning, and long-term data on social relationships and kinship. In July 2023, off the coast of Dominica, Maalouf et al. observed 11 members of a known sperm whale social unit, comprising two typically separate and unrelated family groups, gathering unusually close to the surface. Although these subgroups are generally distinct in their foraging behavior and social associations, they formed a cohesive cluster as a birth unfolded. Using drone footage, the authors documented the 34-minute delivery of a calf, followed by a period of intense, coordinated activity in which multiple adult females surrounded the mother. According to the authors, in the hour after birth, the group displayed strikingly cooperative behavior; individuals from both family groups took turns physically supporting and lifting the newborn to the surface, likely assisting it in breathing. The entire unit remained tightly organized during this critical period. In addition, there were close passes by Fraser's dolphins and brief interactions with pilot whales. Several hours after the birth, the sperm whale cluster gradually dispersed into smaller, more typical foraging groups.
