Baby Humpback Whales Whisper To Get Mom's Attention

A recent study suggests humpback whale calves whisper to get their mother's attention.

According to a few researchers who eavesdropped on a conversation between a baby humpback and its mother, the calf seemed to be making something of a whale whisper.

Using detachable acoustic tags, researchers trailed eight calves and two mothers for a total of 48 hours each as they swam near the Exmouth Gulf off Western Australia.

The recordings, described in Functional Ecology, are the first of their kind.

After a quick listen, researchers noted they weren't exactly sure what they'd heard.

"It's like a squeaky sound, and some of them are really like grunting sounds," Dr. Simone Videsen of Aarhus University in Denmark said. "When they're born, these whales are around five meters long," she added, noting that this discovery is "pretty big considering it's a baby."

Dr. Videsen said her team of scientists used special sound and movement recorders that they attached to the whale's skin by suction cups.

"We were really surprised because humpback whales are really vocal normally and they have these long songs," she said. "But when you look at the communication pattern between mother and calf, you see that they're often silent and they do produce these weaker signals."

By "whispering" to its mother, scientists believe that the calf is less likely to be overheard by other predators and male humpback whales who are in search of a mate.

"There are lots of killer whales in the area which are predating on these calves," Dr. Videsen said, "and they can use these sounds between mother and calf like homing cues." But the low volume of their calls risks being overwhelmed by engine noises emitting from nearby ships.