The Ten Things I Learned About Whale Sharks From the Experts on an Expedition to Isla Mujeres

By: Elizabeth Henry

It’s hard to believe that it has already been two months since I went to Isla Mujeres with some of my Beneath The Waves colleagues to swim with whale sharks. The opportunity to spend three, seven-hour days on a boat to swim with the largest fish on the planet in the largest aggregation known to science was just too hard to pass up.

The week long expedition was coordinated by the PangeaSeed Foundation. Their mission is to use art to generate awareness about ocean and environmental issues. I was fortunate enough to spend my three days aboard the vessel Angelina amongst shark experts, biologists, and professional filmmakers. I will never forget what I learned and did my best to capture it all below:

1. Whale sharks (Rhincodon typus) have lived for 60 million years. I am sure I read this statistic somewhere while studying up for this trip but I can’t quite put into words how it makes you feel when you are swimming next to one.

2. They are classified as endangered with extinction by the International Union for Conservation of Nature (IUCN). Populations have been cut in half over the last 70 years due to threats such as overfishing and shark finning.

3. The pros and cons of the tourism industry. It’s a delicate balance of the local island economy. The tourism industry is boosted by people wanting to see the endangered animals. A live whale shark is worth $300,000 to the island whereas a dead whale shark may be worth only a few thousand dollars.

4. The whale shark is the largest known extant fish species, reaching lengths of up to 46 feet and weighing up to 12 tons. The Angelina was 31 feet long according to our Captain, Wicho. Almost all of the whale sharks we saw were much longer than our boat.

5. Whale sharks are not related to whales. They are in fact a member of the shark family, although they eat by filtering plankton like whales do.

6. The largest fish on the planet eats the smallest food. Whale sharks eat plankton, algae, krill, small squid, tuna eggs, and crab larvae.

7. It is one of three species of sharks that are filter feeders. Whale sharks, basking sharks, and megamouth sharks are all filter feeders, meaning they feed by straining food particles out of the water through their gills. This is hypnotizing to watch up close.

8. Whale sharks have about 3,000 tiny teeth. I was a deer in the headlights when I found myself face-to-face with a whale shark’s gaping mouth. As it swam towards me, I quickly got out of the way but not before getting a good look inside. Along the mouth are 300-350 rows of tiny teeth. Fortunately these are not used for eating!

9. Although they aren’t the fastest swimmers they are tough to keep up with. Although most descriptions of whale sharks imply they are slow-moving, you will find that when swimming alongside one they are actually quite difficult to keep up with thanks to their giant tails!

10. We have to do what we can to save these animals. THINK! The things you do while traveling can have an impact on these species. Eat a variety of local foods and avoid eating seafood for every meal while vacationing. When researching your transportation, consider renting a private boat for your trip from an operator whose practices are safe and sustainable. Use biodegradable sunscreen to protect both your skin and the whale sharks’ food, because you’ll be swimming in it! Cut down on your use of disposable plastic. Maybe you don’t need that straw with your soda!

I overheard someone on the boat say, “even if you don’t believe in global warming, what’s the harm in just trying to make things a little better?” You know, they have an excellent point.

A special thanks to Captain Wicho and Herman of the Angelina for educating us about the whale shark industry practices in Isla Mujeres, keeping us all safe, and for the great guacamole. To learn more about PangeaSeed Foundation and Sea Walls visit

To learn more about Beneath the Waves visit

Stay up to date on how you can get involved by joining our newsletter.

Want to support our research?

Click below to donate or contact us for more information.

Learn about Beneath the Waves’ Initiatives