There are comparatively few hard scientific facts known about whale sharks. Their migration patterns and where they mate and pup are uncertain. Here in Sogod Bay, Southern Leyte whale sharks are to be found between November and May, but their whereabouts during the rest of the year are a mystery. Research into whale sharks continues and doubtless our knowledge about them will improve over time, but the following is a summary of what is currently known.
The whale shark is the world’s largest fish with lengths of up to 13 metres and weights of over 21 tonnes being reliably recorded. There are numerous unconfirmed reports of much larger ones. Here in the waters near Padre Burgos the average length is between 7 and 8 metres, and the largest I have seen personally was about 10 metres long. The smallest recorded live whale shark was just 38 cm long.
The whale shark is a filter feeder, with a staple diet of plankton and krill. Water and food is sucked into the mouth, the food filtered out and the water expelled through 5 pairs of gills. Although they have huge mouths, their teeth are tiny and they pose no significant threat to humans, so it is safe to swim at close quarters with them.
Whale sharks live between 70 and 120 years and reach sexual maturity around 30 years of age. The mother produces hundreds of eggs which hatch inside her body and she gives birth to live pups.
Whale sharks like warm waters and are to be found anywhere around the tropical belt, with the most significant aggregations being reported off western Australia, eastern Africa, eastern central America and around the Philippines. They are capable of swimming at depths well in excess of 1,000 metres but frequently feed close to or even on the surface. Reports of whale sharks being stranded on beaches or coral reefs, particularly at nighttime, are common.