Despite decades of environmental change and population recovery, eastern Australian humpback whales appear to have maintained their historical adult size.
Eastern Australian humpback whales grow at an extraordinary pace, reaching approximately 10.9 meters (35.8 feet) in length by age five. By six or seven years old, they have already attained about 90 percent of their eventual adult body length, according to new research led by Griffith University.
The findings, published in Marine Mammal Science, suggest these whales grow faster than humpback populations studied elsewhere. “This is faster growth than other humpback whale populations that have been measured,” said lead researcher Stephanie Stack, a Griffith University PhD candidate.
Drones Reveal How Quickly Humpback Whales Grow
To investigate how humpbacks develop throughout their lives, researchers measured 865 individually identified whales between 2021 and 2024. Using drones to photograph the animals from above, they calculated body lengths without physically disturbing the whales. Long-term photo-identification records helped the team track growth across newborn calves, juveniles, and adults more than 40 years old.
The measurements showed that humpbacks experience their fastest growth during early life, with the rate gradually declining as they approach adult size. Including calves and young whales allowed scientists to examine these crucial developmental stages directly rather than relying on estimates derived from older animals.
Replacing Decades-Old Whaling Data
“These are also the first contemporary growth curves developed for eastern Australian humpback whales using measurements from living animals, updating knowledge that has relied heavily on measurements collected during the commercial whaling era in the mid-20th century,” Stack said.
Eastern Australia’s humpback population has recovered dramatically since commercial whaling ended, becoming one of the world’s most successful examples of whale conservation. Despite this population rebound and decades of environmental change, the new measurements closely match historical estimates of adult humpback size in Australian waters.
“These new growth curves establish a baseline for investigating how whale biology may respond to changing environmental conditions.”
Understanding Whale Health in a Changing Ocean
“Understanding how quickly whales grow provides another piece of the puzzle in understanding the biology of this recovering population,” Stack said. “Growth influences many aspects of a whale’s life, including its health, energy requirements and potentially the timing of reproduction.”
The new growth curves provide researchers with a reference point for tracking possible changes in humpback development as ocean conditions shift. Future measurements could help determine whether environmental changes are affecting growth patterns in this recovering population.
“As environmental conditions continue to change, having robust biological benchmarks like these will be essential for understanding how whale populations are responding,” Stack said.
Reference: “Contemporary Growth Curves for Individual Humpback Whales in Eastern Australia Using Aerial Photogrammetry” by S. H. Stack, T. Fettermann, B. McGovern and S. M. Bengtson Nash, 15 October 2026, Marine Mammal Science.
DOI: 10.1111/mms.70296
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