Tiger Sharks Don't Floss

by B. N. Sullivan

One day we were diving at Puako, Hawaii in the general vicinity of the area we call the Petting Zoo (described in a previous post). We were swimming close to the bottom edge of the rubble slope, where the sandy plain begins, looking for little creatures and seashells.

I spotted what I though might be the edge of a shell sticking out of the sand. When I picked it up, I realized that it was not a shell at all. It was a shark's tooth -- the first I had ever found in the water. I put it into the small mesh drawstring bag I always carried with me, and we continued our dive.

When we got home that day, I took the shark tooth out of my little mesh bag, washed it, and set it aside to dry out. That's it in the photos on this page. We didn't know what species of shark the tooth had belonged to, but we joked that whatever kind it was, he obviously didn't floss!

A few weeks later, an old friend of mine from Honolulu came to visit, along with her young son. To entertain the little boy while his mother and I chatted, I got out a few books that had a lot of pictures and gave them to him to look at. One of those books was about sharks. After awhile, the boy interrupted our conversation, telling us he needed to show us something right away. It was a picture of a Tiger Shark tooth, and it looked exactly like the one I had found. This was an unexpected piece of information.

Don't get me wrong -- we always knew that there were Tiger Sharks (Galeocerdo cuvier) in our waters. We knew that fishermen in the area caught one occasionally, and local surfers reported seeing them from time to time, yet in all our years of diving we had never seen one. In a way, this was surprising. Since we dived so frequently in the same area, we reckoned there was a high likelihood that sooner or later we would cross paths with at least one of everything that was out there. We had seen plenty of sharks, but no Tiger Sharks.

Much as birdwatchers do on land, we always have kept a record of every marine species we've encountered. We call it our Critter Log. Most of the sharks we had seen were reef sharks: Whitetips, Blacktips, and Grays. From time to time we would see a pelagic shark, like a Hammerhead, or a Whale Shark. We also had come face to face with one Galapagos Shark and one Thresher at Puako, but never a Tiger Shark. Still, the tooth I had found was proof that the Tiger Sharks definitely were there in what we thought of as our territory.

Surfers we knew who claimed to have seen Tiger Sharks in the water said they only appeared during dawn patrol, or just as the sun was setting. We began a lot of our dives very early in the morning, and when we did night dives at Puako, we usually entered the water at dusk. Thus, we surmised that if we ever saw a Tiger Shark at Puako, it probably would be either very early in the morning, or at the outset of a night dive. This thought was reinforced by the fact that our sighting of the Galapagos Shark was very early in the morning, and it was as we were descending for a twilight dive that we had our single encounter with a large Thresher Shark.

I had found the Tiger Shark tooth well offshore, and at a depth of more than 100 ft. Thus, in addition to believing there was a good probability that one day we would cross paths with a Tiger Shark at Puako, we imagined there also was a strong likelihood that we would see it well away from shore, in deep water. After all, these are large, pelagic animals -- and anyway, that was where I had found the tooth!

From time to time we discussed all this, usually in conjunction with showing what we now knew was a Tiger Shark tooth to another diver. As it turned out, our first and only encounter with a Tiger Shark was nothing like we had anticipated. It happened in the early afternoon, inshore, in relatively shallow water. So much for probabilities and likelihoods!

In the next post we'll tell you all the details of that first encounter with a Tiger Shark.