Humpback Whale Filmed Feeding Her Calf in Rare, Underwater Video

Rare video footage has captured a female humpback whale and her calf interacting and provided a detailed look at the species' nursing and suckling behavior that is seldom captured in such detail.

Researchers with the University of Hawai'i's Mānoa Marine Mammal Research Program (MMRP) monitored the whales using non-invasive suction-cup tags that had been installed with cameras, acoustic recorders, pressure sensors and accelerometers.

The filming took place in the waters around Maui, Hawaii, over 10 days and involved seven whale calves who were tagged for periods between 5 and 20 hours.

"We can actually see what these animals are seeing and encountering and experiencing themselves," Lars Bejder, MMRP Director, said in a press release. "It's quite unique and rare footage that we're obtaining, which is allowing us to quantify these nursing and suckling bouts that are so important."

The filming was part of a project designed to quantify nursing behavior in Maui, a breeding ground for humpbacks that sees thousands of whales visit between November and March. According to the Maui Ocean Center, approximately 10,000 humpbacks make the 3,000 or so mile journey from Alaska to Hawai'i each year. It is one of the longest migrations of any species in the world.

The researchers hope to calculate the frequency and duration of nursing behavior, as well as record social interactions between different whales. Drones are being used to capture additional information, including the size and body composition of 120 whales of different ages.

In 2019, the team used similar methods to capture bubble-net feeding behaviors in Alaska. Humpback whales use streams of bubbles to cast "nets" around their prey. Bejder and colleagues filmed the activity from above using drones and at eye level using suction-cup tags fitted with cameras and sensors.

"Combining these data sets across the foraging and the breeding grounds is really going to tell us something about the importance of these different habitats for these animals," said Bejder.

It is all part of a larger project led by MMRP and other scientific organizations to track the health of humpback whales and understand what is behind the declining number of whale sightings in Hawaiʻi and Alaska.

While scientists have noticed a drop in the number of sightings since Hawaiʻi's humpbacks were delisted from the Endangered Species List in 2016, no one knows why that is.

Though yearly variations can be expected, researchers point to a drop in the number of mother-calf pairings of more than 50 percent between 2014 and 2017. Changes in habitat use and food availability as well as climate change have been put forward as potential explanations.

Humpback mother and calf
Stock humpback mother and calf. Researchers have published unique footage of a humpback whale nursing her calf from the calf's point of view. Barb_Malc/iStock