Researchers have discovered how deep-sea sharks are able to float, even when they are not swimming. For the study, the researchers used cameras fixed onto the fins of deep-sea sharks. Earlier, scientists thought that sharks were negatively buoyant or neutrally buoyant.

Researchers have discovered two species of these deep-sea creatures with help of photos and data captured by the swimming sharks. These are sixgill and prickly sharks that have a bit of positive buoyancy that drives them toward the surface.

Scientists at the University of Hawaii and the University of Tokyo attached a flashlight-size camera to deep-sea sharks in order to study their swimming habits. Scientists at the University of Hawaii and the University of Tokyo carried out the research. This camera is capable of working at depths of up to 6,500 feet (2,000 meters), and can be used with a strobe in order to get light to take pictures in dark, deep waters.

The scientists also used an accelerometer and magnetometer in the camera pack, on a small metal band fixed onto the shark’s fin.

According to study co-author Carl Meyer, an assistant researcher at the University of Hawaii at Manoa's Hawaii Institute of Marine Biology, “We set a date and time we want it to come off, the metal band breaks and drops off the shark and the package floats up to the surface of the ocean [and] sends us a satellite sign of where it is".