Las Cabezas De San Juan… Nature At It’s Best

Cabezas de San Juan

Receiving area with “ceiba” tree.

This week I went back to nature. I got on my SUV, drove to the town of Fajardo and visited “Las Cabezas de San Juan”, a nature reserve unlike any other in Puerto Rico. Fajardo is a small town on the northeastern tip of Puerto Rico, about a 30 to 40-minute drive from the San Juan Metroplex. And believe me, I enjoyed every minute of this trip.

However, there was one thing that I didn’t like. So I might as well get it out of the way and get on with my article. Their website is seriously in need of a makeover. At first sight it seems pretty but it’s so cumbersome and unfriendly that I simply hated it.

That said, here’s how to contact “Las Cabezas de San Juan”. Their phone numbers are: 787-722-5882 and 787-860-2562. Their email is: And, for good measure, their website is, in case you insist on torturing yourself.


There are tours in Spanish and in English. My wife and I took the English tour. It lasted around two and a half hours. We both speak perfect Spanish but I wanted to see how good the English version actually was. It was great!

There are different prices for regular visitors, students and senior citizens. We paid regular admittance at $10 each plus a sales tax of 7%. Students and seniors pay less.


One important warning: they do not allow “walk-ins”. The only way to visit the reserve is with a reservation. And to make reservations you need to call in or do it on their website. That’s why —in my opinion— they should improve that website quick.

Enough with my rant.

Cabezas de San Juan

Sandy beach with “talacia” beds

Our tour started at 2:00pm sharp and we were advised to arrive around 1:30pm. When you enter the grounds the first thing that you find is a well-kept parking lot and a receiving area. There is a beautiful “ceiba” tree in front that looks like it’s several hundred years old.

When you arrive they look you up in a reservations list and hand you a waver to sign. There are no ferocious animals or poisonous reptiles in the area but there are plenty of opportunities to get hurt if you don’t follow your guide’s instructions or wander off into the wilderness on your own. So I guess that’s why they do it.

Cabezas de San Juan

Our guide “Antonio” was knowledgeable and friendly.

The tour started right on time. Our guide Antonio led us to a well maintained tram that was our mode of transportation for the following two and a half hours. Visitors are not allowed to venture into the reserve grounds on their own. ¡And even if they were, the place is huge! There are 438 acres of beautiful unspoiled terrain in the reserve. So walking is hardly an option anyway.

You can take as many pictures or video as you like. In fact, feel free to click on any of the pictures in this post to see it larger.


Antonio mentioned that there are seven main kinds of ecosystems in the reserve, but as the afternoon progressed he only mentioned four. The first is the coral reef, which acts as a barrier between the reserve and the see. It’s also the breeding ground for many species of mollusks and crustaceans.

Cabezas de San Juan

Talacia beds at the extreme left

Second you have the “talacia” beds. Those are the dark green patches that you see several yards beyond the coastline. They are the natural habitat for star fish and sea cucumbers. They are also a very important source of food for manatees, an endangered sea mammal that lives in this area.

Then you have the sand shore. At first glance many people would think that a beach is only made up of sand and water. But they’d be wrong. Beneath the sand there are actually thousands of tiny organisms. And if you take a closer look you’ll actually see hundreds of little holes. Those are made by ghost crabs; tiny tan-colored crab that blend in perfectly with the color of the sand.

Cabezas de San Juan

Termite nest.

Along the way you’ll see huge termite nests everywhere. They too have a specific function in the forest. They decompose dead trees and return the nutrients back to nature. The huge brown structures that they call “home” are actually made up of saliva and excrement.

After passing “fisherman’s trail” (a place where fishermen would carry their boats from the beach to the lagoon) we made our first stop at a boardwalk that traverses a section of the mangrove and “Laguna Grande”.

“Laguna Grande” is not just any lagoon. It’s a bioluminescent lagoon (one of three in Puerto Rico) that’s filled with millions and millions of microscopic organisms called dynoflagellates. But that’s not the only reason why this lagoon is different. This lagoon is also of an intense re-brown color, and I’ll explain why in a minute.

"Laguna Grande" at "Cabezas De San Juan"

“Laguna Grande” at “Cabezas De San Juan”

There are four main types of mangroves in this area. They are: white, black, button and red. To the untrained eye they’ll probably all look the same. But Antonio actually took the time to show us the differences between them.

White mangrove

White mangrove

One way to tell mangroves apart is by their roots. White mangroves have white roots sticking out of the ground. They act as tiny snorkels that allow the plant to breath. Mangroves live in salt water. But since the plant doesn’t actually need salt to live, it excretes if from the underside of its leaves.

The roots on the black mangrove are bigger and grow deeper into the wetland. The leaves are also different. They are elongated and they are always pointing upward. This protects them from the sun. They too excrete the salt from the bottom of the leaves.

The button mangrove has a round seed that gives it its name. You find it in the driest areas of the wetland. It has ornamental use. You can grow it in a pot or next to sidewalks. However, it doesn’t tolerate too much salt.

Cabezas de San Juan

Boardwalk over the wetlands

And finally, red mangrove is found in the innermost part of the wetland area. It has bigger leaves that have a waxy feel to them. Its roots look like hundreds of branches growing out of the water. They’re called aerial roots because they stick out from branches. They add anchorage and leverage to improve the stability of the tree. They also excrete the salt close to the root through lenticels.

Cabezas de San Juan

Antonio shows decomposing organic material

The wood of a red mangrove is red because of the great amount of tannins that it contains. This is the same stuff that you find in red grapes. And it is also what gives the surrounding water that intense red-brown color.

Wetlands derive their particular smell from sulfur. Leaves from the red mangrove fall into the water and decompose at the bottom. This provides an excellent feeding area for small fish but it also accounts for that pungent smell that we all love to hate.

Cabezas de San Juan

Natural Pool

Natural pools are often created within the red mangrove area that protect smaller fish from being eaten by bigger ones. They grow there until a certain point and then they get out.

After leaving the mangrove area we passed by “Jayuya Beach” on our way to a rock beach called “Lirios Beach”. “Jayuya Beach” is one of the most important beaches in the reserve because there are remnants of the Taíno and Pre-Taíno cultures such as ceramics and skeletons.

Lirios Beach, Cabezas de San Juan

The wind is so strong that trees grow sideways.

“Lirios Beach” is what is called a rocky shore. The wind in the area is so strong that many trees actually grow sideways. There is a coral reef, not that far from the shore, that protects the beach from the ravaging surf. There is also volcanic rock on the right side of the coast and the rock on the beach is more typical of the Island’s rivers than of its beaches.

Lirios Beach, Cabezas de San Juan

Lirios Beach

Towards the end of the trip we arrived at “Cape San Juan” Lighthouse, Puerto Rico’s second oldest operating lighthouse. It was built in 1880 and first used in 1882. Most people think that lighthouses only serve to guide vessels at sea. But actually they can also tell them where they are. Each lighthouse has a certain periodicity which tells captains which one they are actually looking at. The one in Fajardo rotates at exactly 15 revolutions per minute.

Cabezas de San Juan

Cape San Juan Lighthouse

Lighthouses in Puerto Rico are operated by the US Coast Guard but the base structure of the one in Fajardo houses a small museum where visitors can see live specimens of juvenile iguanas, hermit crabs, sea cucumbers, star fish and even actual dynoflagellates that you can see glowing in the dark.

And of course, Antonio explained each and every one of them to our group in perfect detail.

Cabezas de San Juan

The view from the lighthouse is spectacular!

Finally, we climbed to the roof of the lighthouse to enjoy a spectacular view of the actual “Cabezas de San Juan”, the eastern islands of Icaco, Vieques and Culebra, and the northern shore of Puerto Rico with the Caribbean National Rainforest (better know among the locals as “El Yunque”) as a backdrop.

We returned to the receiving area close to 4:30pm after an outstanding day of exploration, learning and entertainment. “Las Cabezas De San Juan” is a true gem that every visitor to Puerto Rico should enjoy. And if you are a landscape photographer like me you’ll feel like a kid at a candy store. Mmmmmm!


Oh, and before I forget, there are other activities that take place during the night time, like excursions to the bioluminescent lagoon. Ask at the visitor center for details.

Enjoy Puerto Rico,

©2014,Orlando Mergal, MA

Bilingual Content Creator, Blogger, Podcaster,
Author, Photographer and New Media Expert
Tel. 787-750-0000, Mobile 787-306-1590



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