Through electronic tagging, tissue sampling and photo identification, a lot can be discovered of the behaviours of Ocean Giants. Whale sharks can dive up to a mile deep, and routinely swim over 6000 miles each year. Giant manta rays can also travel long distances. Whale sharks need approximately 25 years to mature, and routinely live for 100 years. There is still only very limited knowledge of their reproductive habits, but manta rays are known to have annual ovulating cycles, but have the slowest reproductive rate of all elasmobranch species.