I think a lot of people (especially nervous new divers) sometimes imagine divers jump in the water and are instantly encircled by an array of sharks. Sadly although this does sometimes happen (like the awesome pair of reef sharks that swam through the openwater course I was assisting with a while back to the students delight) its fairly unusual. Diving with sharks often requires carefully planned trips to specific locations and sometimes special equipment....like...erm...planes.
This is the Shark Research Institute spotter plane which flies out of La Paz, Mexico. Now as you can imagine if its big enough to be seen from the air its probably a big animal. Actually, its the biggest of all known sharks, all know fish even - the Whale Shark (Rhincodon typus). If you're lucky on your whale shark trip, shortly after the plane flies over your boat it will change direction as the captain follows instructions from his eye in the sky and shortly after that someone will spot something like this in the water. They are not particularly difficult to spot from above water on account of being 30 feet long and polka-dotted.
In water it can be different. As whale sharks are harmless filter feeders (just like those basking sharks) they favour areas with lots of food which means low viz. The boat will drop you on course to be alongside where the shark is moving towards and then people on the boat will talk you onto the shark. Which means you jump in the water and then swim like hell all the while having no idea where the shark is until suddenly you see this:
at which point I defy you not to be awestruck (not by the photo - when you actually do it obviously). Its truly awesome (especially if like me you've wanted to do it since you were 6 years old). Lots more on Whale Sharks to come (including much better photos - by the way the top 2 were taken with a disposable f*lm camera after the e900 died - can you tell? Oh and yes that pink fringing on the right edge of pic 2 is my thumb - stupid disposable cameras with no lens barrel!).