You can’t find a great white shark in any aquarium in the world, but you can find whale sharks, the biggest fish in the sea. What gives? The last time an adult white shark was put on display at an aquarium in Japan, it died three days after it arrived. The only aquarium to successfully keep a white shark in captivity was the Monterey Bay Aquarium in California. Between 2004 and 2011, they displayed six white sharks, the longest of which stayed for over six months before it was released.

One challenge is that great white sharks are ram ventilators, meaning they have to move forward through the water with their mouths open to breathe, which makes them weak when they are caught. The Monterey Bay Aquarium monitored the sharks in an ocean pen before transporting them to the aquarium in a specialized tank with life support.

Another challenge is that adult white sharks eat mammals. So the aquarium brought in baby sharks that were around four feet long, but they were used to moving quickly through the open ocean and had a problem bumping into the walls of the tank. In 2011, they released the last shark after 55 days on display. Unfortunately, it died shortly after being released and the aquarium hasn’t tried again since.