A remarkable event has been captured for the first time in great detail: a group of sperm whales coming together to support the birth of a calf. On 8 July 2023, scientists observed and recorded two family groups of sperm whales (Physeter macrocephalus) uniting in the Caribbean Sea near Dominica. They took turns assisting with the birth and helping the newborn calf stay afloat to take its initial breaths.
“Our results suggest that kin and non-kin engaged in sustained, cooperative postnatal care, taking turns to support the newborn and maintain group cohesion, in contrast to historical kin-segregated foraging patterns,” writes a cross-disciplinary team led by computer scientist Alaa Maalouf from MIT’s Project CETI.
“These findings provide rare quantitative evidence of direct allocare [caring for non-biologically related offspring] in cetaceans and can lend support to the hypothesis that transient, structured cooperation during birth is a key mechanism sustaining complex sociality in sperm whales.”
Sperm whales are among the most social creatures on Earth. They live in groups, and their survival depends heavily on cooperation and collaboration. Within their large clans, which can include up to 10 individuals, the smallest units are matrilineal, led by a mother and her daughters, while adult males typically live separately, joining female groups only to reproduce.
The dynamics of this social structure during birth are not well understood. Before this event, only four sperm whale births had been reported in the past 60 years, and those were either based on anecdotes or observed during whaling activities, suggesting some level of community support without clear documentation.
In July 2023, Maalouf and his team were conducting fieldwork off Dominica’s coast as part of Project CETI, an initiative to decode sperm whale communication using advanced recordings and machine learning.
Initially, everything seemed normal until 9:50 am local time, when researchers encountered a group of 11 sperm whales at the surface, consisting of two unrelated matrilines that typically forage separately. This unusual behavior prompted scientists to deploy observational tools, such as hydrophones and drones, to capture audio and video.
The ensuing events were extraordinary. At 11:12 am, a pregnant whale named Rounder began delivering her calf, a process completed in 34 minutes. Other adult female whales formed a synchronized circle around her. By 11:46 am, the birth was marked by blood plumes and the appearance of the newborn whale.
Immediately after the birth, the entire group took turns helping the newborn stay afloat to breathe, as newborn sperm whales likely cannot swim independently right away. Other cetacean species also appeared, seemingly curious.
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“The group rapidly transitioned to cohesive and highly active behavior; individuals took turns lifting the newborn, physically supporting and pushing it to the surface, consistent with supporting a negatively buoyant neonate. This phase continued for about an hour, during which time the entire unit remained tightly grouped,” the researchers write.
“In addition, there were close passes by Fraser’s dolphins (Lagenodelphis hosei) and brief interactions with pilot whales (Globicephala macrorhynchus), which encompassed the sperm whale cluster and occasionally dove beneath them.”
To analyze the observations, researchers utilized machine learning and computer vision to identify individual whales, track movements, and study group interactions during the birth.
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The analysis revealed that every whale in the group of 11 took at least one turn supporting the calf in the hour after birth. A core group of four whales – Rounder, the mother; her half-sister Aurora; Ariel, an unrelated juvenile; and Atwood, an older relative – covered about 96 percent of the support time.
Audio recordings indicated an intense and active soundscape during the birth, though the study focused more on the whales’ actions than their vocalizations.
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Despite not analyzing the audio, the study sheds light on the complex social behaviors of these intelligent creatures. “Our results provide quantitative evidence for the paradigm that calf survival, particularly around births, drives selection for the social bonds underpinning the complex social organization that has evolved in sperm whales,” the researchers write.
“These findings place the complexity of sperm whale birth behavior and coordination in comparative context with terrestrial mammals, including primates and humans, raising questions about the cognitive architectures and communication systems that support and mediate these behaviors.”
The research has been published in Science Advances.
