Young dolphins have been found to possess unique receptors on their tongues that are sensitive to fatty acids, providing fresh understanding of their development and feeding behaviors.
Researchers have revealed that juvenile bottlenose dolphins have unique receptors that help them detect the fatty acids found in their mother’s milk. These discoveries, detailed in the journal Marine Mammal Science, shed light on the growth, feeding practices, and communication of these oceanic mammals.
This new research questions earlier beliefs about the sensory functions of cetaceans. Unlike their terrestrial counterparts, dolphins and other marine mammals have a significantly diminished sense of smell, which is not effective in underwater settings. As a result, scientists have theorized that dolphins rely on alternative methods to sense their environment and locate food.
Fat is crucial for delivering energy and aiding brain development in dolphin calves, which rely solely on their mother’s milk during the very beginning of their lives.
“We examined the tongue of a young Indo-Pacific bottlenose dolphin and identified special structures likely assisting in fat detection,” explains the study’s lead author, Hinako Katsushima, from Hokkaido University’s Graduate School of Environmental Science in Japan. “At the back of the tongue, there’s a V-shaped arrangement of taste receptors specifically designed to pick up fatty acids. These receptors contain enzymes that help break down fat, aiding the dolphin in sensing and processing it.”
In a following experiment, the researchers provided young dolphins with a selection of two liquids: one was milk, and the other a cloudy liquid. The dolphins exhibited an unexpected preference for the cloudy solution. This supports the idea that dolphins can differentiate between the two liquids, but the reason for their avoidance of the milk remains unclear. One explanation could be that they found the milk unfamiliar, given it was a blend from two different females, leading to a cautious approach to new foods—a behavior known as neophobia.
“Our results indicate that the capability to detect fatty acids in their mother’s milk is part of a specialized ‘fat taste’ system, which may assist dolphins in evaluating the nutritional quality of their diet,” states Assistant Professor Takashi Hayakawa of Hokkaido University’s Faculty of Environmental Earth Science, who oversaw the study. “In natural settings, where high-fat diets are essential for survival, this ability may give dolphins an evolutionary advantage, enabling them to select nutritious milk from their mothers and later assess the dietary value of their catch.”
This study paves the way for deeper understanding of how marine mammals perceive and engage with their surroundings, including their communication and foraging behaviors in the wild. Additional research will be necessary to further explore the intricacies of this ‘fat taste’ system and its functionality among other marine creatures.
