Biologists have observed Bryde's whales preying on fish with unique foraging patterns in waters near south China's Weizhou Island, using creative teamwork to trap their harvest near the ocean surface.
The foraging techniques were discovered by Chinese and Thailand biologists, who have been working closely to protect Bryde's whales, one of the national first-class protected aquatic animals in China.
Weizhou Island, located in the Beibu Gulf, is China's youngest volcanic island. Bryde's whales, a species mainly living in tropical and subtropical waters, are frequently spotted preying on fish in the waters near Weizhou Island.
Patcharaporn Yaowasooth, a marine biologist at the Department of Marine and Coastal Resources of Thailand, said that during her joint research with the Chinese partners, she discovered a great number of similarities in the ways that Bryde's whales in Thailand and China hunt. This includes corkscrew-style swimming and bubble-net feeding -- a learned method of cooperative hunting in which a group of whales traps fish within a net of bubbles formed by exhaling through their blow holes.
"Almost all of them in Thailand have this feeding. And (the similarities extend) up to the species and fish that they eat, also," she said.
Yet, the scientists also saw unique behaviors that are not seen in Thai waters, as a Chinese professor from the School of Life Sciences of Nanjing Normal University explained.
"The Bryde's whale living in the waters near Weizhou Island have two unique foraging behaviors. In one case, they were discovered emerge from the water, tilt to the right, and then whirl around in a full or half circle, just like one creates swirling motion while scooping. We named the new hunting technique as 'self-rotating foraging' or 'swirling foraging'. In another case, they conduct teamwork, making up a circle with their bodies and then spiraling up to the water surface to trap the fish inside before eating up the harvest. This is a quite unique foraging technique," said Bingyao Chen, a professor at the university's School of Life Sciences.
Bryde's whales, like other species, are capable of learning non-instinctual behaviors from each other, allowing unique behaviors to develop in different parts of the oceans.
Chinese, Thai biologists discover unique foraging pattern of Bryde's whale
