Swimming in the water of Hawaii's Big Island is a fun experience. But it can be more exciting if there are dolphins swimming around and jumping out of the sea too. For many people, it would be a wonderful dream to swim with these lovely animals! However, this may not be good for dolphins. They may get hurt because of human interaction  . Dolphins are active and usually look for food at night. In the day, they like to rest in shallow bays . Many people think the dolphins are awake during the day as they swim. But when they sleep they rest half of their brain and keep the other half awake to breathe, so they may be sleeping even when they're swimming in the water. From 2010 to 2013, spinner dolphins   of Hawaii's Big Island were exposed to human activities more than 82 percent of the time, according to Julian Tyne, a researcher at Australia's Murdoch University. The National Oceanic and Atmospheric Administration (NOAA) says disturbing the animals in their near-shore habitat could force them to swim to less favorable places, putting them at risk of attack by sharks and other animals.  Besides, when people are around, dolphins become more active. Thus, they can't get enough sleep. "Disturbing their resting behaviors can actually affect their long term health and the health of the dolphin population," Ann Garrett of NOAA's National Marine Fisheries Service told the Associated Press. As a result, the NOAA wants to make rules to help protect the dolphins. For example, the agency   may ban swimming with the Hawaii spinner dolphins. Or they may stop people from swimming in shallow bays when the dolphins are resting. Tour operators must also be taught to watch for signs to know when the dolphins are in their resting state. Which of the following about dolphins is NOT true?
They spend most of their time sleeping at night. They like to stay in shallow bays during the day. They keep half of their brain awake while sleeping. They may be sleeping even when they're swimming.