Electric Eel

Despite their serpentine appearance, electric eels are not actually eels. Their scientific classification is closer to carp and catfish.

These famous freshwater predators get their name from the enormous electrical charge they can generate to stun prey and dissuade predators. Their bodies contain electric organs with about 6,000 specialized cells called electrocytes that store power like tiny batteries. When threatened or attacking prey, these cells will discharge simultaneously, emitting a burst of at least 600 volts, five times the power of a standard U.S. wall socket.

They live in the murky streams and ponds of the Amazon and Orinoco basins of South America, feeding mainly on fish, but also amphibians and even birds and small mammals. As air-breathers, they must come to the surface frequently. They also have poor eyesight, but can emit a low-level charge, less than 10 volts, which they use like radar to navigate and locate prey.

Electric eels can reach huge proportions, exceeding 8 feet (2.5 meters) in length and 44 pounds (20 kilograms) in weight. They have long, cylindrical bodies and flattened heads and are generally dark green or grayish on top with yellowish coloring underneath.

Human deaths from electric eels are extremely rare. However, multiple shocks can cause respiratory or heart failure, and people have been known to drown in shallow water after a stunning jolt.

Electric eels are extremely common throughout their range.

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Anaconda

A member of the boa family, South America’s green anaconda is, pound for pound, the largest snake in the world. Its cousin, the reticulated python, can reach slightly greater lengths, but the enormous girth of the anaconda makes it almost twice as heavy.

Green anacondas can grow to more than 29 feet (8.8 meters), weigh more than 550 pounds (227 kilograms), and measure more than 12 inches (30 centimeters) in diameter. Females are significantly larger than males. Other anaconda species, all from South America and all smaller than the green anaconda, are the yellow, dark-spotted, and Bolivian varieties.

Anacondas live in swamps, marshes, and slow-moving streams, mainly in the tropical rain forests of the Amazon and Orinoco basins. They are cumbersome on land, but stealthy and sleek in the water. Their eyes and nasal openings are on top of their heads, allowing them to lay in wait for prey while remaining nearly completely submerged.

They reach their monumental size on a diet of wild pigs, deer, birds, turtles, capybara, caimans, and even jaguars. Anacondas are nonvenomous constrictors, coiling their muscular bodies around captured prey and squeezing until the animal asphyxiates. Jaws attached by stretchy ligaments allow them to swallow their prey whole, no matter the size, and they can go weeks or months without food after a big meal.

Female anacondas retain their eggs and give birth to two to three dozen live young. Baby snakes are about 2 feet (0.6 meters) long when they are born and are almost immediately able to swim and hunt. Their lifespan in the wild is about ten years.

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Ground pangolin

The Ground pangolin (Manis temminckii), also known as Temminck's Pangolin or the Cape Pangolin, is one of four species of pangolin which can be found in Africa and the only one in southern and eastern Africa. Although it is present over quite a large area, it is rare throughout it and notoriously difficult to spot. Its scarcity is partly because it is hunted by humans for its scales, which are used in love charms, and partly because it is often burnt in bush fires. It is designated as an endangered species by the United States Fish and Wildlife Service,
With the exception of the underside, it is covered in extremely hard scales. When threatened, it usually will roll up into a ball to protect the vulnerable belly. The scales on the tail can also be used as blades to slash at attackers.

The Ground pangolin can grow to a length of about 1 metre, with the tail typically between 30 and 50 cm. It has a disproportionately small head, powerful hindlegs, and small forelegs. Walking is done almost entirely on the back legs with the heavy dragging tail acting as a counterweight.

Like other pangolin species, it is largely nocturnal, although it is also entirely terrestrial and usually found in savanna or open woodland, generally feeding on termites or ants. It is well adapted to this, with a very long (up to 50 cm) sticky tongue which extends deep into its abdominal cavity. Although it is capable of digging its own burrow, it prefers to occupy disused holes dug by a warthog or an aardvark or to lie in dense vegetation, making it even more difficult to observe.

The animal was named for the Dutch zoologist Coenraad Jacob Temminck.

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Flying squirrel

 Flying squirrels are not capable of powered flight like birds or bats; instead, they glide between trees. They are capable of obtaining lift within the course of these flights, with flights recorded to 90 meters (295 ft). The direction and speed of the animal in midair is varied by changing the positions of its two arms and legs, largely controlled by small cartilaginous wrist bones. This changes the tautness of the patagium, a furry parachute-like membrane that stretches from wrist to ankle. It has a fluffy tail that stabilizes in flight. The tail acts as an adjunct airfoil, working as an air brake before landing on a tree trunk.

The colugos, Petauridae, and Anomaluridae are gliding mammals, which are similar to flying squirrels, because of convergent evolution. A few mammals can glide through the trees, but they do not actually fly (like birds and bats). They have a membrane of skin on either side of their body.

The Siberian flying squirrel ranges from the Baltic Sea in the west to the Pacific Ocean in the east.

Prior to the 21st century, the evolutionary history of the flying squirrel was frequently debated. This debate was clarified greatly as a result of two recent molecular studies. These studies found support that flying squirrels originated 18–20 million years ago, are monophyletic, and have a sister relationship with tree squirrels. There are four hypotheses as to why gliding has evolved in mammals: economical locomotion, foraging optimization, evasion of predators, and control of landing forces.

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The Rafflesia arnoldii.

The flower with the world's largest bloom is the Rafflesia arnoldii. This rare flower is found in the rainforests of Indonesia. It can grow to be 3 feet across and weigh up to 15 pounds! It is a parasitic plant, with no visible leaves, roots, or stem. It attaches itself to a host plant to obtain water and nutrients. When in bloom, the Rafflesia emits a repulsive odor, similar to that of rotting meat. This odor attracts insects that pollinate the plant.

Another enormous flower found in Indonesia is the Amorphophallus titanum, or Titan arum. It is also known as the "corpse flower" for its unpleasant odor. Like the Rafflesia, the Titan emits the smell of rotting flesh to attract pollinators. Technically, the Titan arum is not a single flower. It is a cluster of many tiny flowers, called an inflorescence. The Titan arum has the largest unbranched inflorescence of all flowering plants. The plant can reach heights of 7 to 12 feet and weigh as much as 170 pounds!

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Rare Sighting of All-White Orca Whale

The rare all-white orca whale was spotted swimming with its pod. Photo by E. Lazareva / Newscom

On a summer morning in 2010, off the coast of Kamchatka in eastern Russia, scientists made a rare discovery. Photos, released earlier this week (and posted on our Retina Tumblr blog) document what may be the first verified sighting of its kind: an all-white adult orca whale.

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What were the largest species of all time? Does the Tyrannosaurus rex make the list?

Titanoboa was one gigantic snake. It lived around 58 to 60 million years ago, a scant several million years after the mass extinction that wiped out the dinosaurs. It could grow 42 feet or more in length and weigh more than a ton, vastly outslithering the previous fossil record holder, a 40-million-year-old, 33-foot-long snake called Gigantophis. But Titanoboa is just one proud inductee in the Prehistoric Giants Hall of Fame. Meet the other record-holders.

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Largest herbivorous dinosaur

Of all the dinosaur superlatives, “biggest dinosaur ever” is one of the most prized. The trouble is that we don’t really know who deserves the title. Sauropods like Apatosaurus (once known as “Brontosaurus”) and Diplodocus, both at roughly 70 feet long, seemed to be the champions during the 19th century, but since then a variety of even bigger sauropods has been found.

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