OF all the beasts divers encounterunderwater, whales and dolphinsare among the most thrilling.Costa Rica is blessed with a greatdiversity of whales and dolphins;while most species do not normallyapproach divers, some have becomelocally famous for their curiositywhen approaching humans.Many Pacific-coast dive sitesare in the lee of rocks, islets and islands.This is the preferred habitatof humpback whales rearing theiryoung, courting and mating. Everyonce in a while, these giant mammalsglide over to check out diversin action, sometimes even with their young. Most of thetime they want nothing to do with people and should be leftalone – but the times they are curious can be unforgettable.The vast size of a humpback can be extremely intimidating;one misplaced fin or fluke and a diver could be brokenlike a fragile toy doll. Even the wash of water thrownbehind a huge moving tail fluke could blow apart a diverlike a scarecrow in a tornado. The biggest pectoral fins inthe world, covered with hard, rough knobs used in battlewith other whales, would also do a diver damage.Yet these giants are gentle, as long as they are notchased, bothered or approached. When humpbacks chooseto approach divers, their awareness and precision of movementis astounding in such large creatures; they make surethe wash from their fins blows not even a diver’s hair outof place.I know of at least two different dive guides who werepushed away, without injury, by the enormous pectoral fins.Both times the divers had tried to approach a mother andher young. With humpback whales, you’d better let themcome to you.False killer whales, or pseudorcas, may approach youin Costa Rica. Although not nearly as big as humpbacks,these seven-meter-long dolphins would make the biggestshark in the world look for someplace else to be. Travelingin packs of close to 100, when they near the coast theyoften fan out and start eating tuna, snapper, jack and theirapparent favorite: roosterfish.When they happen upon divers, they have no fear whatsoever.Pseudorcas will often swim right over to your facemaskand look you in the eye from a few centimeters away.They might nudge you or even bite your fin. These gestures,from a living monster, will be sure to get your heart going.Many people would say that being in the water withthem is not a good idea. However, not only have they yetto hurt anyone but, believe it or not, here in Costa Ricathese wild animals have been known to give gifts of large,live fish to people.Rough-toothed dolphins also bring gifts to divers occasionally;small fish, seaweed and plastic are among the objectsthese mysterious dolphins have been known to bringto humans. Like most dolphins that grow to the approximatesize of humans, they are skittish and liable to spook atthe slightest thing. But they sometimes approach divers fora close look and can even be quite playful.Bottlenose dolphins are famous for their affinity forhanging around people. Here in Costa Rica they are not asfriendly as some might think, often keeping to their ownbusiness. Rarely do they stop to inspect and swim withdivers. When they do, they tend to be in groups of 1,000 ormore. I guess that gives them a little more confidence.Spinner dolphins also often travel by the thousands, butthey seem to enjoy checking out divers who are respectful.These high-energy dolphins are all action; watching themswim around, you might crane your neck from all the turning.They rarely visit dive sites, but, if they do, you willknow it. The sound of a huge pod underwater is like thenoise of a big party with everyone chattering in a verystrange language.Atlantic spotted dolphins chatter a lot as well but arenormally found in much smaller groups. They are amongthe most friendly and curious of Costa Rica’s dolphins, andhave the same reputation around the Caribbean, where theyare the focus of many countries’ “swim with dolphins”tours. Here, they are hard to find and skittish, but you justmight get lucky on any dive.Pantropical spotted dolphins and pilot whales also mightapproach divers, but they will be covered at a later date.For information or to send in reports or contributions,call 835-6041 or e-mail email@example.com.