Joint U.S. and Japanese research shows tiger sharks repeatedly swim up and down through the water to search for prey. 

The Hawaii Institute for Marine Biology said in a statement Monday that researchers installed digital cameras and devices that record swimming speed, depth, temperature and acceleration on four tiger sharks west of the Big Island. 

Carl Meyer, the U.S. lead on the project, says scientists have long debated the reasons why tiger sharks practice yo-yo diving but have only recently developed the tools to measure the behavior. The institute says research results are due to be published by the end of the year.

The study is joint project between the Hawaii Institute of Marine Biology, University of Tokyo, the Japanese National Institute for Polar Research, and the University of Florida.