For 34 minutes off the coast of Dominica, eleven sperm whales worked together in a way scientists had never documented before: they helped one of their own give birth.

Researchers from Project CETI were tracking whales in July 2023 when they noticed the unusual gathering. What they captured with drones, underwater microphones, and shipboard photography became the most detailed account of a sperm whale birth ever recorded—and the first to show cooperative birthing behavior in the species.

The mother, a whale researchers call Rounder, was surrounded by adult females who took turns diving beneath her, often belly-up, heads oriented toward her genital slit. When the calf emerged tail-first, the whales immediately began what Alaa Maalouf, a researcher with Project CETI, called “a highly cooperative period of caregiving”—lifting the newborn to the surface, squeezing it between their bodies, and pushing it toward the air.

Newborn sperm whales are negatively buoyant. Without fully developed organs that help adults float, they sink. For three hours after delivery, every whale present took turns keeping the calf afloat.

Perhaps most striking: roughly half the whales present weren’t directly related to Rounder. The group included members of two separate matrilines that don’t typically spend time in close proximity. Yet they worked together seamlessly, their vocalizations shifting at key moments—suggesting coordination that goes beyond simple genetic obligation.

The findings, published Thursday in Science and Scientific Reports, add to growing evidence that sperm whale societies are built on something richer than kinship alone.

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