Exploring the Bat Population of the Panamanian Rainforest – by Night!

Panama City skyline

What is the first thing you think about when you hear Panama? Maybe it’s the infamous Panama Canal, or the jaw dropping skyline of Panama City? It could be the beaches or the rainforests. For me, it was the animals!

As a biology graduate student, I was lucky enough to be able to travel to Panama for 3 months to explore Panama’s biodiversity and immerse myself in its nature. Panama’s location, size and climate all make for a truly unique place. With roughly 60km of land between the Atlantic and Pacific oceans, filled with lowlands and mountains, Panama is full of many valuable ecosystems. From wet lowland rainforests, to mountain rainforests, to dry forests, wetlands, mangroves and reefs, Panama has it all, and all in close proximity! In just one day you can go from hiking in the mountain forest to snorkeling in the reefs. Panama is also the land connection between North and South America and provides valuable land crossing for many species- and curious human explorers.  

Mountainous rainforest

My personal journey began in Gamboa. Running along the Panama Canal, is the rainforest of Gamboa, only a 30-minute drive from Panama City. This pristine protected land is home to thousands of species of plants, mammals, birds, insects, and of course, bats! These bats are what I came looking for, and what I will tell you all about.

The bats of Panama

With over 120 species of bats, Panama is the perfect place to find the species you are looking for. As a traveller, you will likely get a chance to spot a couple during dusk, waving through the trees as they begin their evening hunt. As a scientist, Panama is bat heaven!

Mostly unseen by our eyes, bats are everywhere in the night sky. At times you could catch a glimpse of one flying by, and just like that it is gone! The best way to see them, without actually seeing them? Using ultrasonic detectors! These small devices convert the bats ultrasonic echolocation sounds into audible clicks, chirps and buzzes we can hear. Bats use echolocation to see and interact. Instead of relying on their eyesight, bats emit an ultrasonic sound from a special organ in their noses, which bounces off the things in their environment and comes back to them. Based on how much ultrasonic waves come back, and their direction, the bats know what is around them. Different objects have different abilities to absorb and reflect the ultrasonic waves, so a bat will be able to easily distinguish between a tree, a building or a river. Now if that’s not cool, I don’t know what is! A few other interesting features of the bats are their big ears, razor sharp claws on their feet and wings, and their long, thin, skin like wings that allow them to fly and change direction quickly.

A few species you are likely to find include the vampire bat (Desmodus rotundus) which gets its name from -you guessed it- feeding on blood, the Jamaican fruit bat (Artibeus jamaicensis) whose primary diet is tropical fruits, and the fringe-lipped bat (Trachops cirrhosus) which eats insects and frogs.

A typical night in the field

The main purpose of my visit to Panama was to study the personality differences between bats. Just like humans, animals too have personalities, which can be quite striking! Some bats are lazy and slow, others are energetic and quick, some individuals are curious and others are shy.

The fun all begins at dusk. Bats are nocturnal, so all our work was conducted during the nighttime. You thought getting lost in the jungle during the day is scary? Imagine in the middle of the night! Although it took a while for me to get over my fears, I learned to trust my partners and embrace nature. As peaceful as the jungle is during the day, it is even more so at night.

To prepare for our night in the field, at around 5pm we would gather in the lab and start packing. Nets, headlamps, sugar water, water bottles and snacks… all the essentials for a night of bat catching. Each day we varied the location so that we can catch different individuals from different colonies.

Gamboa rainforest

Like birds, bats are safely caught using mist nets. Mist nets are made from a fine mesh suspended from two poles, about 3 meters in length and 2 meters in height. When a bird or bat flies into the net, they get captured in the baggy pockets. These nets do not cause any harm to the animal, but they do scare them. So, it is important to act quick and remove the bats as soon as they get caught!

To free the bats, we gently removed their legs and wings from the net, holding their wings tight to their body so they don’t escape. Hand position is very important as bats can turn their heads almost 180 degrees and bite if you are not careful. These painful bites are dangerous as wild bats carry many diseases, including rabies.

Depending on the species of bat we were interested in catching, we varied our net location and methods. For bats that like water and fishing, we set up the nets over streams and near rivers. For bats that like forested areas we set up nets in semi-open spots in the forest. And for our most lucrative bat, we set up MP3 players under the nets with the calls of the tungara frog, the preferred meal of the fringe-lipped bat! And what great deceivers we were, fooling the poor bats into thinking we have a meal for them, when instead we had a net.

When we caught a bat of interest, we gently put it into a small fleece bag and hung it from a tree. The bags are soft enough so that the animals cannot injure themselves, but thick enough so that they can’t chew through it… and let me tell you, there were many attempts! As there are so many species of bats in Panama, and we were only looking for two of them, we ended up with a lot of by-catch bats, meaning bats of other species. If a by-catch bat was caught, we would carefully examine them, give them sugar water if they looked weak and hungry, remove any parasites they had crawling on them, and set them free away from the net.

Of the bats of interest, not all were always selected to come home with us. If a female was pregnant or lactating she was released. The chosen ones were taken back to the lab with us, where we would do our behavioural experiments. The experiments were quick and easy, simply observing how the bats would behave in a new cage environment. After just a single night in captivity, the experimental bats would be fed, given water and released back in the wild. It was especially important to release the bats in the same place they were caught, as we wanted to ensure that they knew where they were and can orient themselves home.

Bats in the lab

Who else can you find in the rainforest at night?

Hiding along the bushes and trees we encountered monkeys, coatis, agoutis, deer and in some locations, caimans! Just picture this. You are wandering through the pitch-dark rainforest, with just a headlamp to light your path. You hear a noise in the bushes and turn your head to the side. And what do you see? A dozen glowing yellow eyes scattered across the ground, watching you. What a fright! Although most were quite small, the largest one we saw was approximately 1.5m. Just big enough to be able to do some damage if he decided to attack. Luckily, the caimans we met were very calm and never approached us or showed much interest in what we were doing.

But scariest of it all? The dreadful, horrific, terrifying monsters commonly known as… mosquitoes. These tiny pests, to whom I unwillingly donated so much of my blood, were the worst part of my experience. Luckily, I came equipped with long pants and long sleeved tops, mosquito mesh to put over my clothes and natural repellents.

Overall my time in Panama was an amazing and unique experience that I am very happy to have lived through. Although Panama City and the Canal are absolutely magnificent and inspiring feats of human architecture and design, I urge visitors not to stop there. Much more impressive are the rainforests and underwater reefs, only a short journey away which can be added to your already planned itinerary! And if you find yourself in Gamboa on Sunday, be sure to check out Bat Nights, an educational outreach event hosted by the Gamboa Bat Lab where you can learn more about the bats and see several up close and in person!

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