The researchers knew something was wrong. In July 2023, while tracking a sperm whale in the Caribbean Sea, they found a larger group — eleven whales gathered near the surface — but the animals weren’t behaving as marine biologist Shane Gero expected. “They were just laying there calmly,” he said.
The team launched two aerial drones and filmed. About an hour later the calm ended: the whales began thrashing and a rush of blood stained the water. At first Gero feared a predator attack. Instead, the footage captured a birth.
The drones recorded labor and the moment the newborn’s fluke emerged — sperm whales are born tail-first. Underwater microphones picked up the whales’ clicks; decoding those sounds is central to Gero’s work as lead biologist for Project CETI. Over hours of recording, the scientists watched individuals, including whales with no genetic ties to the mother, helping keep the calf at the surface so it could breathe.
Two papers in Science and Scientific Reports present the most detailed record to date of a sperm whale birth. Combining drone video, machine learning and long-term field observations, the team identified the mother as a whale named Rounder.
Sperm whales live in matrilineal units composed of grandmothers, mothers and daughters; males leave in adolescence. Rounder’s Unit A included two matrilines that usually don’t spend much time together. Roughly half the whales present were not directly related to her. Still, they all helped. Newborn sperm whales are negatively buoyant because their nasal oil-filled sacs are not yet developed; without support they sink. For the first three hours after birth every whale present took turns keeping the calf afloat.
“The behaviors that we’re seeing — in supporting the mom, in supporting the newborn — reflect a complex cooperative society that can’t just be explained by, ‘Oh, you’re related,'” Gero said. “There’s something richer there — in which they live in a society where the expectation is, ‘I will help you so you will help me.'”
Philippa Brakes, a behavioral ecologist at the University of Exeter who was not involved in the studies, said the findings point to a mix of cultural and innate responses. “An analogy for humans might be that some of us like sushi, others like fries — but when it comes to helping people in extremis, most of us would respond to someone who was giving birth in the street,” she said.
Gero and his team will continue to analyze the audio and video to map social dynamics and answer remaining questions. He said a broader takeaway applies to people as well: cooperation across differences helps overcome challenges. “We succeed by overcoming obstacles by working together. In spite of the fact that we’re different and unrelated,” he said. “And that’s a pretty important message, I think, these days.”