Norfolk Island's Most Avid Bird Watchers: Tiger Sharks

Norfolk Island is tiny as far as landmasses go. The craggy island sits 877 miles east of Australia. It measures a mere 13.4 square miles in area. Yet some things about Norfolk Island aren't small. Need proof? Just ask the scientists who study the island’s tiger sharks.  

“This was the most tiger sharks we had ever caught in one day and they were the biggest males and biggest females we had ever seen,” biologist Lauren Meyer told National Geographic (NatGeo). Her team found that the tiger sharks who circle the island are a full six feet longer (15 feet) on average than the same fish in other regions (9 feet). There are more of them, too. A 2022 study found that the waters around Norfolk Island boast a greater number of tiger sharks than any other region on Earth.  

Sporting snubbed noses and stripes like the big cats from which they take their name, tiger sharks aren't picky eaters. Dissections of their stomachs have revealed everything from fish and seal meat to whole sea turtles, oranges, and the license plates of cars. To grow them Norfolk Island-big, though, takes a little extra.   

“You need something special to be able to sustain that many large sharks,” biologist Charlie Huveneers told NatGeo. At first, researchers thought cow remains might be the culprit. Local farmers throw them into the ocean around the island. But stomach samples revealed that cow only makes up 10% of the tiger sharks’ diet. 52% of their stomach contents was seabird meat.  

“Seabird rafting movement at dusk is the perfect (chance) for sharks to come up and use their big, flat noses to suction these birds off the surface,” Meyer said. 

Reflect: Why do you think it's important for scientists to study different animals and their behaviors in various environments?

Gif of tiger sharks from GIPHY.