What is the currently understood purpose of the great hornbill's casque?

What is the currently understood purpose of the great hornbill's casque?

• A. It stores water
• B. The purpose is not fully understood, but it may be used for display or in fighting
• C. It helps regulate body temperature
• D. It is used to crack nuts

Answer: (B)

The casque on the great hornbill’s bill is a hollow bony extension, and its exact function isn’t known for sure. What researchers do observe is that the casque is involved in social interactions: birds use it in courtship displays to attract mates and in displays or confrontations with rivals, suggesting a role in visual signaling and competition. Some evidence also points to the casque acting as a resonator that helps amplify or project calls through the forest, which could aid communication over long distances. Because multiple possibilities fit the data and no single function is definitively proven, the best understanding is that its purpose isn’t fully known, with display and fighting-related roles being the most supported ideas. It isn’t intended for storing water, regulating body temperature, or cracking nuts.

The casque on the great hornbill’s bill is a hollow bony extension, and its exact function isn’t known for sure. What researchers do observe is that the casque is involved in social interactions: birds use it in courtship displays to attract mates and in displays or confrontations with rivals, suggesting a role in visual signaling and competition. Some evidence also points to the casque acting as a resonator that helps amplify or project calls through the forest, which could aid communication over long distances. Because multiple possibilities fit the data and no single function is definitively proven, the best understanding is that its purpose isn’t fully known, with display and fighting-related roles being the most supported ideas. It isn’t intended for storing water, regulating body temperature, or cracking nuts.