Behaviour

The Port Jackson (Heterodontus portusjacksoni) shark is a benthic, buccal pumping species that remain motionless for extended periods of time.

Do Sharks Sleep?

Sleep is ubiquitous across the animal kingdom but despite anecdotal reports of sleep-like behaviour in nurse sharks and other seafloor-dwelling species, the question of whether sharks actually sleep has been intensely debated but remains unknown. A key criterion for separating sleep from other quiescent states is an increased arousal threshold. True sleep is characterised by a lack of movement that can be rapidly reversed, and a decreased awareness of surroundings.

The Fabulous Spawning Ritual of Striated Surgeonfish

Schooling striated surgeonfish

During a seven-year study of reef sharks in Tahiti, ethologist Ila France Porcher also observed the behaviours of various fish species. Here, she offers a detailed description and insights into the dynamic and mesmerising spawning events of the striated surgeonfish, which take place every year in the South Pacific.

Seeking Eye Contact: Fish Gaze Reveals Self-Awareness

For many years, I held a weekly feeding session for the resident reef sharks and their visitors in the study area where I observed their behaviour. If I had enough shark food, I would scatter crumbs into the water for the fish after the sharks had left. The fish knew this, so they had to wait, and while they were waiting, they were excited.

The Bahamas’ Tiger Beach: Petting Zoo or the Real Deal?

Divemaster strokes a tiger shark near the bait box behind him, Tiger Beach, Bahamas.

Tiger Beach in the Bahamas is firmly established as one of those global dive destinations of which almost everybody has heard. Its fame is largely derived from the many published images of its most celebrated visitor—Galeocerdo cuvier, the tiger shark.

The Underrated Nurse Shark

Plentiful nurse sharks attended the sessions I held during my shark study in Tahiti. They are heavily-built animals with large, graceful fins, a long, pennant tail, and small eyes. They forage on the sea floor for a variety of foods at night and sleep in grottos in the coral during the days. Though these unusual sharks typically lie around on the sea floor, they are also capable of clambering.

Sharks: Turning Fear into Love

A new style of shark dive has been developed by Jim Abernethy, of Scuba Adventures in Florida. In a dramatic demonstration that “shark huggers” are right, all his guests do with the sharks now is to stroke them! Jim was the pioneer who first demonstrated the peaceful way that sharks will interact with divers, especially when their curiosity has been aroused through the offer of a snack.