UNSW Study Finds Humpback Calves 1,500 km South of Accepted Calving Zones
Updated
Updated · spacedaily.com · Jun 28
UNSW Study Finds Humpback Calves 1,500 km South of Accepted Calving Zones
1 articles · Updated · spacedaily.com · Jun 28
Summary
A 2025 UNSW-led study logged 209 neonate humpback calf records across Australia and New Zealand, including two live sightings in Tasmania near 43 degrees south—the highest-latitude neonate record reported worldwide.
That pushes the observed eastern Australian calving range about 14 degrees latitude, or roughly 1,500 km, beyond the long-accepted southern limit near Gold Coast Bay; Western Australia extended about 1,300 km.
Strict newborn criteria underpinned the finding: calves had to be under 5 meters or about one-third of the mother's length, with supporting signs such as fetal folds, undeveloped dorsal fins, placenta or attached umbilicus.
Movement data suggest some mothers give birth before migration ends: all 94 New South Wales cow-calf pairs with direction data were heading north, as were all three in New Zealand.
The authors say most calves are still likely born farther north, but the results imply temperate migration corridors can also be calving habitat—raising management concerns over shipping, fishing gear, noise and other coastal threats.
Newborn whales are now appearing in busy southern waters. How will we rewrite the rules of our oceans to protect them?
With humpback populations falling, is their expansion into colder birthing waters a sign of adaptation or a desperate gamble for survival?
Southern-Born Humpback Calves Signal Major Migration Shift and New Conservation Risks
Overview
A groundbreaking study by the University of New South Wales has revealed that humpback whale calves are now being born in temperate southern waters, far from their traditional tropical calving grounds. This discovery challenges the long-held belief that humpbacks migrate to warm, calm tropical waters to give birth, where conditions help newborns survive by reducing energy loss and predation risk. The presence of calves in cooler regions suggests a significant shift in whale breeding behavior, prompting scientists to reconsider why these migrations occur and what environmental changes might be driving this unexpected pattern.