Electric Eel | Harpy Eagle | Tapirs

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1. Electric Eel
2. Harpy Eagle
3. Tapirs
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Electric Eel

The rivers of South America provide life to one of the planet’s richest population of plants and animals. Long and winding through the tropical rain forests these rivers create a multitude of flooded forests and diverse aquatic ecosystems.

Within these murky habitats exists an animal sometimes feared for it’s peculiar and shocking behavior. Found in the muddy, slow-moving streams, lakes and tributaries of the Orinoco and Amazon rivers is the sometimes deadly creature named the Electric Eel.

This long, slender animal has a snake-like body and flattened head – all covered in dark gray or brown scaleless skin with an orange and yellow tinted underside. It can reach lengths up to 9 feet long and weigh nearly 45 pounds. It has poor eyesight, so it must rely on other means to seek out and capture it’s prey. It’s secret: electricity.

The Electric Eel possesses 3 distinct organs that make up 80 percent of the fish’s body and allow the generation of various electrical charges. These organs, identified as the main electrical organ, the Hunter’s organ and the Sachs’ organ are made up of thousands of electrical generating cells called electrocytes. They can produce both very strong and weak electric charges, which are utilized for defense, hunting, navigation and even communication.

Through the use of a lateral-line system of motion-sensitive hairs along it’s body – the electric eel can detect slight pressure change in the surrounding water. When it searching for prey that may be nearby, it emits two rapid electric pulses.

These quick burst of electricity causes the prey to twitch involuntarily and alert the electric eel to its presence. With a series of high-voltage pulses (as many as 400 per second), it then paralyzes and consumes its prey. This entire process happens so quickly that it can be difficult to see in real-time. Even very young eels possess these important hunting skills.

Electric eels communicate using low electric organ discharges. The frequency at which weaker electric pulses are produced varies between males and females. The fish can detect these signals and interpret information about other individuals in the water.

Despite the name, the Electric Eel is not actually classified as an eel at all. It is considered a knifefish – a species of freshwater fish that lack pelvic fins and are related to catfish and carp. These fish also lack a dorsal fin but instead have an elongated anal fin that helps them maneuver through the water – moving forward, backward and even hovering in place.

There are more than 200 knifefish species found in South America, each one makes use of electrical signals for communication and prey detection. The Electric Eel, however, packs the greatest punch – capable of generating electric shock pulses up to 850 volts, though most discharges are around 10 volts. They are also known to leap out of the water to deliver a much more powerful and direct charge – often this is used as a defense behavior. These amazing predators can stun a large horse and kill a full grown man with a full direct hit.

Electric Eels are found widely distributed across much of northern South America. Though fish, they actually breath air from the surface, a trait that allows them to survive in otherwise poorly oxygenated and muddy streams.

The mouth of an electric eel is very sensitive due to the abundance of blood vessels present for oxygen absorption. Shocking prey is believed to protect the mouth by reducing the amount of thrashing by captured prey.

The eels feed on a variety of prey including fish, crustaceans, insects, reptiles, amphibians and even small mammals.

During the dry seasons, males will build a nest made from saliva to house more than than 1,000 eggs laid by the female. Males will defend the nest and the newly hatched fry.

The typical lifespan of electric eels in their native habitat is unknown but animals thriving in managed care can live up to 15 years, females will often live longer – sometimes up to 20 years.

Harpy Eagle

The canopy of the Amazon rainforest often extends more than 100 feet into the sky. Even there, however, sloths and the many primates that reside there are not safe. In these high reaching tree tops is a deadly predator.

One of the largest raptors on the planet – with a wingspan of 6 feet and talons up to 5 inches long – the Harpy Eagle is the most powerful and largest eagle in the “New World.”

Named for the Greek mythological creature that was said to be half-woman, half-bird – the Harpy Eagle is bold, striking and dangerous.

Despite living at the top of the forest, the Harpy Eagle rarely flies above the tree cover – instead these agile flyers will soar beneath the canopy and snatch monkeys and sloths from the branches. With talons larger than the claws of a grizzly bear, the Harpy Eagles can carry off large prey weighing more than 15 pounds.

Often the birds will sit patiently in nearby trees and wait (often for hours) for their prey to arrive. Harpy Eagles are capable of turning their head upside down and can fly straight up as well – allowing them to often strike from below as well as above.

Though they prefer to hunt high up in the trees, they will hunt ground dwelling animals, including javelina, armadillos, agoutis and even baby deer. The Harpy Eagles are apex predators in their habitat and have no natural predators – they have even been noted for not being afraid of people.

Harpy eagles are marked by their dark grey feathers over their wings and back with lighter grey and white feather’s on the edge of it’s wings, body and around the face. Some smaller gray feathers create a facial disk that give them an appearance similar to some owls – it is thought that this shaped may focus sound waves to improve the bird’s hearing.

The feathers on the top back of their head can be fanned and stick up especially when the Harpy Eagle may feel threatened or aggressive.

Like many other eagles, Harpy eagles are monogamous and may mate for life. Females are often twice as large as their male counterparts – weighing up to 20 pounds. As parents, they fiercely defend their eggs and young. The mother lays one or two eggs in a clutch, and she only reproduces every two to three years. Both parents incubate eggs, with the female taking most of the responsibility. Newly hatched chicks are all white and can fit in the palm of a person’s hand.

Typically the mother will remain with the young while the father will seek out food and bring it to the nest – however it is the female that feeds the chick by tearing off small pieces of meat and delicately feeding it with her bill.

Young Harpy Eagles grow quickly and reach adult size in 5 to 6 months. They remain with their parents up to two years and reach adulthood by 5 years of age.

Despite being a top predator of their ecosystem – Harpy Eagles face challenges to their ongoing survival. They are non-migratory birds who need large, undisturbed forest regions to thrive. Habitat destruction, logging and poaching have led to the decline of these impressive creatures as well as many other species within their forest home.

Though the Harpy Eagle is the national bird of Panama, this important species is critically endangered throughout most of Central America.

Zoo Miami, the San Diego Zoo and The Peregrine Fund all participate in active breeding programs as well as programs designed to reintroduce many Harpy Eagles back into the wild.


Leaving a recognizable trail through the heavy vegetation of the rainforest floor is a heavy, solitary creature. Featuring a teardrop shaped body – a wide rounded rear and small tail tapering to a more narrow head and snout – the Tapir is the largest land mammal in both Central and South America.

Sometimes mistaken as a large pig – tapirs are actually more closely related to horses and rhinos – a group of hoofed mammals known as ungulates. Tapirs are herbivores, most active at dawn and dusk, they spend most of their time both browsing and grazing for vegetation that includes grass, shrubs, twigs and fruit. As they forage they often move in a zig-zag motion with their short, stocky legs which helps them pass easily through the dense forest growth. Other animals, and even people, will often use the cleared paths created by tapirs.

The tapir’s most distinguished feature is their flexible proboscis-like snout, formed from tissues of their upper lip and nose. They have the ability to manipulate their snout in complex movements with some limited extension as well, similar to an elephant. They can often explore a circular area of ground up to a foot across without having to move their head

Excellent swimmers, tapirs will often flee to the water to avoid predators – something their keen sense of smell can help them detect. They will completely submerge themselves underwater with only their snout, which acts as a snorkel, protruding from the water. Tapirs also rely on water for feeding, cooling off and defecating. Tapirs are also quite swift on land and are even able to traverse mountainous regions.

There are three species of tapir that can be found in various regions from Mexico to to southern Brazil and the Amazon.

The Baird’s tapir is dark brown with a distinctive cream-colored marking on its face and throat and a dark spot on each cheek, behind and below the eye. It is the largest of the three American species with a shoulder height of 4 feet and weighing up to 770 lbs.

Also known as the Central American tapir, the Baird’s tapir was named for American naturalist Spencer Fullerton Baird, who observed the animals in Mexico in 1843. Baird’s tapir are the national animal of Belize and nicknamed the “mountain cow.”

The Brazilian tapir is the most widespread of all tapir species. The Brazilian tapir is dark brown, paler in the face, and has a low, erect crest of fur running from the crown of the head down the back of the neck. Some animals will feature a crest that is a darker brown or black, while on others it is lighter in color. The round, dark ears have distinctive white edges.

The Brazilian tapir is also known as the Lowland tapir and it prefers living where it’s warm, rainy, and humid. Crocodilians (like black caiman and Orinoco crocodiles), jaguars and even green anacondas are its natural predators.

The Mountain tapir is the smallest of the existing tapir species. Found in the cloud forests of the Andes Mountains in northern South America, it has a longer, thick coat and undercoat than other species, to keep warm in this colder climate. They possess a dark reddish-brown coat with lips outlined in white. The Mountain tapir is one of the most endangered mammals in the world.

Currently only two zoological facilities in North America are home to the Mountain Tapir – California’s Los Angeles Zoo and Botanical Gardens and the Cheyenne Mountain Zoo in Colorado. Both zoos support the ongoing efforts to preserve this important and very rare species which is often threatened by over-hunting.

A fourth species of South American tapir was thought to be discovered in 2013 in isolated regions of the northwestern Amazon. However, follow up studies have concluded this type of tapir is not genetically or physically distinct from the Brazilian tapir.

A fourth Tapir species does exist though – found in the southern and central parts of Indonesia, and on the Asian mainland of Malaysia, Thailand and Myanmar. It is the largest of all tapirs and the only existing species in the “Old World” – the distinctly marked Malayan tapir.

Malayan tapirs have a striking black and white coloration which may act as a form of camouflage in the tropical forests in which it lives. These large animals may grow up to 10 feet in length, and stand over 4 feet tall. They typically weigh between 600 and 900 pounds and the females are usually larger than the males.

Juvenile tapirs are born with white markings that include stripes and spots – some say they resemble a fuzzy, walking watermelon. They are able to swim when they are only a few days old. Though mostly solitary creatures, young tapir will often remain with their mothers up to two years. Tapirs may live up to 20 years in their native habitats.

Tapirs are key umbrella species in maintaining the biological diversity of tropical forests where they live. They form an important part of the ecosystem as major seed dispersers – which benefits the ongoing native plant life and helps provide future food sources for themselves and other species as well.

All tapirs are endangered species. Taking steps to help save tapirs – like the AZA’s Species Survival Plan and educating people on the importance of these often overlooked animals, will not only protect future generations of tapir but can helps save other species of plants and animals and ultimately help preserve the world’s rainforest.


Special thanks to the following organizations for their education, research and conservation programs that provided information for this episode:

Akron Zoo
New England’s Franklin Park Zoo
The Peregrine Fund
Reid Park Zoo
San Diego Zoo
Smithsonian’s National Zoo
Tennessee Aquarium
World Tapir Day.org
Zoo Miami

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