Snorkeling with manta rays is one of the coolest things I have done. I didn't have very high expectations, but it seemed too cool to not try. It is a major attraction off the Kona coast of the Big Island, and basically you go into the ocean at night with some sort of light source which attracts lots of plankton. Mantas eat plankton, so come to areas where they are gathered and feed on them. When manta rays eat, they open up the cephalic lobes on the sides of their head, which help direct the tiny food into their mouths. (When they are not feeding, mantas roll up the cephalic lobes in spirals, and they look like horns, which is where the name "devil ray" comes from). The animals are filter feeders, and the water passes out through their gills, trapping the plankton in their mouth for them to eat. Despite their huge size (the reef mantas we met can be up to 16 feet across!!!) their throats are only about as wide as a quarter, so no, they cannot eat people.
There are a couple ways to go see the mantas feeding. One is to be crazy and go out on your own. But it is at night, in the ocean, and this seems like a bad idea (at least to me). Alternatively, you can go with a group in kayaks. You paddle out, jump in the water, and have flashlights to attract the plankton. This was our original plan, but the water where these tours go out was too rough and the trip got cancelled.
The third, most popular method is to go with a tour from Kona proper who take you on a regular (engine powered) boat to the water by the airport. We ended up doing this with
Big Island Divers, and I would highly recommend it. You get to watch the sun set over the water, snacks and drinks, get a manta ray briefing, and when it is dark enough you jump in. They have big lights that are set up on the ocean floor, and each group of snorkelers hangs on to a modified surfboard with a PVC rail to grab, with another pretty big light pointing down into the water. Each snorkel is outfitted with a light at the top, and each company has a unique color so they can keep track of their snorkelers. There are usually some scuba divers that go down and sit at the bottom, with their bubbles coming up.
Then there are the freaking manta rays. They swim so close you have to try not to touch them. They have sensitive skin, and will get sores if you pet them. But at the surface of the water I felt like I had to flatten out to avoid going belly to belly with the beast. When they feed they do a backwards somersault, so their light colored belly is parallel to the surface. The night we were out there were about 31 manta rays there. They can tell them all apart by their unique spot patterns on their undersides, and keep track of who is there when. I think the record number of mantas ever is about 40 animals, so we were there on an amazing night. It was pretty much nonstop action for almost 2 hours. At first the mantas were feeding right under us, which was really intimidating at first, but so amazing. We got to see them somersault, and some of them swim straight up at us, and some below us. With all the lights and the bubbles coming up from the divers on the bottom and bobbing around in the dark ocean and these huge creatures floating around it felt like an underwater rave. It was so bizarre and unique, and even though there may have been 80 people in the water, because you are all snorkeling no one is talking and it is an oddly personal experience, just you and these giants.
