A Whale of a Mystery: Why Do Humpbacks "Gape"?
"The behavior appeared unusual to observers and was recognized as rare at the time of recording."
A study published this month analyzed 66 instances of humpback whales opening their mouths widely—a behavior termed "gaping"—captured in video footage from tourists, whale-watch operators, and drone users. The research specifically examined cases where this behavior occurred outside of normal feeding routines.
Study Details
The peer-reviewed study was co-authored by Dr. Vanessa Pirotta of Macquarie University alongside other researchers. The footage analyzed was sourced from the internet and social media, contributed by members of the public including tourists, drone operators, and commercial whale-watching operators. The behavior was recorded from boats, during swim-with-whale activities, and via drones.
Observations
The gaping behavior was observed in both adult humpback whales and calves. It occurred most frequently when other whales were nearby and outside of typical feeding contexts. During normal feeding, humpback whales open their mouths to take in water containing krill or small fish, then expel the water through baleen plates to trap prey. The gaping behavior differs from feeding in that it occurred without prey present.
Proposed Explanations
The researchers suggested several possible explanations for the behavior, though they stated the cause remains unknown. Hypotheses include:
- Communication or social interaction
- Playful behavior
- Exploration of ocean debris (particularly for calves)
- Cleaning of baleen plates
- Stretching or reaction to a jaw issue
Source Attribution
Dr. Pirotta noted that tourism operators and citizen scientists contribute valuable observations due to the extended periods they spend watching whales and their access to high-quality recording technology. She stated that the behavior appeared unusual to observers and was recognized as rare at the time of recording.