How Do Mother Whales Feed Their Young

October 04, 2022 Post a Comment

A video taken by a camera carried by a baby whale shows underwater nursing behavior from the calf's perspective.
The CATS Cam camera used in the filming incorporates multiple environmental sensors, such as depth and temperature, as well as movement and acceleration by the calf.
The unusual perspective may help researchers better understand the nursing process of a baby whale, including surfacing to breathe while its mother remains underwater and suckling from mammary slits on each side of its mom.

Baby whales, like all young mammals, rely on their mother's milk for their early development. A new video follows a nursing humpback whale and her calf and takes the calf's point of view as it positions itself beneath its mom and begins nursing. A camera placed by researchers in Madagascar on the back of the baby provided the unusual viewpoint.

Researchers from Cétamada, a Madagascar non-profit conducting research, education, and ecotourism awareness raising on whales and other cetaceans, and the bioacoustic communications team at the Université Paris Sud in France have studied humpback whales that breed along Madagascar's east coast, near the island of Sainte Marie.

This is the "first-ever camera attached to a humpback whale calf to study mother-young behavioral interactions," write the researchers in the video. The clip first shows the traveling whales and the calf's visit to the surface to breathe.

A humpback whale calf travels with and suckles its mother, the first time this has been filmed from the calf's view. Note how the calf negotiates the mammary slits on both sides of its mom while the mother slows her pace to better enable her calf to feed. You can also listen for whale calls in the background. The video was recorded using a CATS Cam camera on a humpback whale breeding ground at Sainte Marie Island on the east coast of Madagascar. Video courtesy of (c) CNRS/ Cétamada.

"It is very important for us to collect underwater video footage, Olivier Adam, a professor at Université Paris Sud, told Mongabay, "especially to have information about the mom and calf interactions, the duration of the apneas [breathing cessations, often at the surface], the depth of the dives."

The researchers recorded the video with a CATS Cam camera, a programmable device designed specifically for animal tracking. For studying mother-calf interactions, Adam said, the device combined the video and audio with accelerometers and environmental sensors, to capture temperature, pressure and movement patterns that change as a whale descends or surfaces.

Whales grow up hearing many sounds, including male songs, social calls, and physical sounds produced by breaches or the slapping of tails and pectoral fins. Since 2013, the team studying the eastern Madagascar humpbacks have deployed acoustic tags on mother-calf pairs to learn about their vocal interactions, which were previously mostly unknown.

They used a 3-meter (10-foot) length pole to attach the camera/tag to each whale they track. "We approach the whale very slowly in order to put the cam on the back of the humpback whale," Adam said.

The multi-sensor tags with audio and video capacity have allowed the scientists to better understand mother-calf social behavior as well as assess threats to their changing environment.

During their first year, baby whales are able to stay underwater for only a few minutes at a time. Nursing events typically occur below the surface. Whale calves can't breathe and nurse at the same time, so given the effort it takes for the calf to position itself underneath its mom to suckle, nursing events tend to be short. The milk is 45-60 percent fat, so even short nursing events allow the calf to grow.

A humpback whale mother and calf near the surface. Calves need to breathe every few minutes during their first year, so the pair tends to remain near the surface. Image credit: montereydiver on Best Running / CC BY 2.0.

Without the photographic evidence, the research text says in this video, witnessing suckling by whale calves at any time is extremely rare. In a 2017 study of nearly 200 mother-calf humpback whale pairs in Hawai'i, researchers observed only four clear nursing events. These calves suckled for roughly 31 seconds (range 15 – 55 seconds) at a time before returning to the surface to breathe.

Scientists have previously placed a "whale cam" on a juvenile minke whale to get that first-person view of the animal's movement and feeding habits in the Antarctic.

According to the Madagascar research team, the new video is the "first time [nursing behavior is observed] from the calf's view." The footage suggests that the mother slows her pace to accommodate her nursing calf and shows the calf surfacing to breathe while its mom can stay below.

"Such video recording is an amazing opportunity to study maternal care in humpback whales," the scientists concluded in the text. "With better knowledge of humpback whales, we can better protect them."

A humpback mother with her calf at the surface to breathe. Newborn calves are roughly 4-5 meters (13-16 feet) long and transition to eating solid food after a year of sustenance on their mother's rich milk. Image credit: flickkerphotos on Best Running / CC BY-NC-ND 2.0.

Citation

Zoidis, A., & Lomac-MacNair, K. (2017). A note on suckling behavior and laterality in nursing humpback whale calves from underwater observations. Animals, 7(7), 51.

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