Views of Panama

The Manatee Expedition

In search of the intriguing manatee, a scientific expedition led by Héctor M. Guzmán of the Smithsonian Tropical Research Institute traversed the Changuinola River and the San San Pond Sak wetland in an attempt to determine the size of the manatee population as well as their distribution, food sources, and the principal dangers they face.

By: Javier Pinzón
Photos: Javier Pinzón and Shutterstock


It is said that science happens in the most beautiful and obscure corners of the planet, and there must be some truth to this. I recently joined a scientific expedition that traveled to the Changuinola River and the San San Pond Sak wetland in the Panamanian Caribbean basin in search of manatees. The astonishing and splendid landscapes we traversed are open to any visitor wishing to admire the gorgeous natural environment of this country.

The study, led by scientist Héctor M. Guzmán of the Smithsonian Tropical Research Institute, seeks to write the natural history of these charismatic animals by determining their population size, distribution, food sources, and the principal dangers they face.

To acquire this data, we leave the laboratories on the island of Naos in Panama City, and after nearly twelve hours of travel along the Pan-American Highway, we reach Changuinola in the province of Bocas del Toro. The San San wetland has been an internationally protected site since 1993, when it was included on the RAMSAR list, which identifies wetlands that are important for the conservation of global biological diversity and sustaining human life. The protected area spreads over sixty-three square miles and encompasses the Negro, San San, and Changuinola rivers.

Upon arrival, we meet Meme, a native of these parts who grew up hearing stories of manatees. He considers them “his old friends,” the kind of friends “you never see” —in the most literal sense— but you know they are there. He will serve not only as our local guide, but also as a bridge between science and folk wisdom. All the information passed down to him by his father and his father’s father will now help us generate scientific data and identify the habits, movements, and diet of these large animals.

Early one sunny morning, we creep slowly along the Changuinola River in Meme’s boat. Our goal is to identify signs of manatee bites on vegetation in order to deduce what they eat and where. Meme, who knows exactly how to zero in on any trace of manatees and understands what each sign means, patiently points the signs out to us until we learn to identify them ourselves; we make methodical observations over the next seven miles. Manatees lack teeth, so they suck and inhale branches and leaves, leaving behind very distinctive marks. These animals, which can grow up to ten feet long and weigh more than 3,000 pounds, eat 10% to 15% of their body weight in vegetation every day. So far, Héctor and his team have identified sixteen species of plants that form part of the manatee diet, including grasses, mangroves, shrubs, and aquatic plants.

We are deep in our search for bite marks, collecting information on the geographic location and the plant species the manatees consume, when something wonderful happens: Meme announces that we have come upon a group of manatees. His ancestral knowledge is vital on our expedition: excess tannins and the mix of fresh and salt water turn the river black here, so it is impossible to see what lies beneath the surface. Despite this, Meme is sure that his friends are here, as indicated by the bubbles generated when the manatees exhale. We stay still until we confirm his intuition: very close to the bubbles, two enormous nostrils suddenly emerge to breathe. Guzmán explains that it is likely a female and her baby, since mother and child manatees have a close and long-lasting relationship.

The lovely panoramas prompt me to get out the camera. Meme tells us that the landscape varies day by day, since the local plant life is very dynamic: plants die, move with the current, bloom, and are reborn in different seasons. Guzmán explains that much of the floating vegetation is not native to this region; it was introduced some years ago and has now colonized the riverbanks.

The scientist has studied the manatees of this area for more than two years. This expert in marine life, who has tagged whales, sharks, and whale sharks with satellite transmitters at the extreme southern tip of the continent and descended nearly 5,000 feet below the ocean in submarines, claims that this manatee study has been the biggest challenge of his scientific career because it is not easy to come upon an animal seemingly determined not to be found. He has traveled 1,400 miles and spent 566 hours along the banks of the San San and Negro rivers, much of that time in muscle-powered kayaks. Such are the difficulties of studying a virtually invisible giant.

Researchers used acoustic techniques like sonar and sound recorders to estimate the size of the manatee population in these rivers. They identified manatee silhouettes with side-scan sonar and recorded the squeaks the animals use to communicate. The resulting data revealed that there are probably no more than thirty individuals in the San San and Negro rivers, and that their distribution is based largely on river depth, vegetation, and water temperature. The high density of aquatic plants prevents sonar use in the Changuinola River, so the population is being assessed with autonomous recorders.

The next step in this investigation will be to tag some of the manatees with transmitters that will send the animals’ real-time geographic location to a satellite, showing researchers how much manatees travel and whether they go from one river to another or remain in the same one for extended periods.

Everything we have seen so far has been simply splendid. However, the San San Pon Sak protected area offers more than the chance to float through trees that paint a different picture every day or along tranquil waters that conceal the invisible giants.

The area’s sandy beaches are a nesting site for the largest turtle in the world: the leatherback sea turtle, a direct descendent of the dinosaurs. From May to July, the beaches provide an unbeatable opportunity to observe the sea giants as they lay dozens of eggs. Guzmán managed to place transmitters on some of the animals, and monitoring showed that some were already as far away as Florida, Jamaica, and Puerto Rico.

This natural resource is so valuable that in the year 2000 friends of the protected area organized and created the Association of Residents and Friends of the Coast and Nature (AAMVECONA). In cooperation with the Ministry of the Environment, the group helps conserve and protect two endangered species: manatees and leatherback sea turtles.

The Association also controls access for interested travelers seeking a fascinating natural experience, and may allow visitors to witness leatherbacks nesting. The group has organized night tours, on which they teach visitors not to bother the turtles as they watch the chelonians engaging in the energetic ritual of depositing their future progeny on the beach.

AAMVECONA has set up a platform for viewing manatees in the middle of the mangrove swamp, over the dark waters of the San San River, where manatees often come to feed on banana plants.

Even though the manatees have their defenders, they still face danger. According to Guzmán’s research, the main perils are engine noise, collisions with boats, and habitat destruction. Furthermore, agriculture and cattle ranching cause erosion and chronic pollution.

The only way to protect these populations is to conserve their habitats: river banks, wetlands, and coasts. Conservation requires greater citizen participation and as much help as possible from local governments; all the research being done is aimed at contributing to conservation efforts.

All told, I depart with a gratifying feeling of having been part of this expedition that, in conjunction with previous and future research studies, could lead to the creation of a multi-national program in Central America to protect the manatee along the 1,360 miles of coastline between Belize and Panama. The idea is to create a protected corridor that safeguards manatees and improves the functioning of the entire ecosystem.


How to Get There

Copa Airlines offers daily flights to David (Chiriquí) from North, Central, and South America and the Caribbean through its Hub of the Americas in Panama City. From David, visitors can take local flights to Changuinola or drive the 125-mile highway across the mountains.

For further information, reservations, and to hire guides, contact AAMVECONA: /

Tel.: 507 6547 7214 (during office hours). Cell: 507 6679 7238