Shark Dynamics: Bull Shark vs. Great Hammerhead

Overview

• Event: Rare encounter between a bull shark and a great hammerhead in spring 2021.
• Location: Boca Grande Pass, Florida.
• Outcome: Bull shark attacks and kills a great hammerhead.
• Significance: Provides a unique opportunity to study interactions between apex predators.
• Experts: Dr. Mike Heithaus, Dr. Yannis Papastamatiou, Erin Spencer, Valerie Hagan, Captain Mike Myers.

Initial Footage and Observations

• Video: Viral video showing bull sharks attacking a great hammerhead near the beach.
• Appearance: Great hammerhead gets pinned and torn apart by bull sharks.
• Reactions: Various experts express surprise and interest in studying this behavior.

Bull Shark Characteristics

• Physical Traits: Stocky, superior jaw strength, notorious for aggression.
• Behavior: Known to attack and eat other sharks; typically not seen attacking hammerheads.
• Size: Smaller than hammerheads, around 10 feet max.
• Ecology: Found in various habitats, highly adaptable.

Great Hammerhead Characteristics

• Physical Traits: Sleek, massive, elongated head unique features (cephalofoil), near 360-degree vision.
• Behavior: Agile, capable of precise and rapid turns, typically larger than bull sharks (up to 20 feet).
• Ecology: Difficult to study due to their vast range and size.

Investigation Methodologies

Tools and Techniques

• Biologgers: Comparable to Fitbits for sharks, used to track movements and behaviors.
• Tagging: Sharks tagged with biologgers to obtain 3D movement data.
• Cloacal Swabs: Collecting fecal matter for dietary analysis via DNA testing.

Research Activities

• Boca Grande Pass: Primary location for encounters and deploying hammerhead tags.
• Tag Recovery: Tags track movement for several days before being recovered.
• Camera Tags: Cameras attached to free-swimming bull sharks for direct observational data.

Key Discoveries

Great Hammerhead Insights

• Maneuverability: Superior agility and speed, quick turns, essential for avoiding predators and hunting prey.
• Predator Avoidance: Typically, bull sharks avoid areas populated by great hammerheads.
• Size Advantage: Larger hammerheads tend to dominate bull sharks in encounters.

Bull Shark Insights

• Aggressive Hunts: Capable of hunting in groups, displaying social hunting behaviors.
• Prey Preference: Analysis of swabs showed bull sharks eating other large sharks but no hammerhead-specific DNA.
• Video Evidence: No direct attempt to hunt hammerheads noted from the footage gathered.

Dynamic Interactions

• Behavioral Shifts: Bull sharks may sense weakness in hammerheads and capitalize on it when the latter is vulnerable.
• Social Structure: Bull sharks appear to have a complex social structure, possibly aiding in their hunting strategies.
• Fight or Flight: Hammerheads typically avoid conflict or exhibit defensive behavior when directly confronted.

Case Study Re-Analysis

• Injury & Predation: The specific hammerhead may have been injured or compromised before being attacked by bull sharks.
• Unusual Encounter: Likely not a common event; exceptional circumstances lead to predatory behavior.

Conclusion

• Predatory Dynamics: Both species respect territorial and ecological boundaries but will exploit vulnerabilities.
• Research Implications: Continuous study needed to understand fully the predatory hierarchies and interactions of these apex predators.