Reptiles have been around for 300 million years, and during the age of the dinosaurs, they ruled the Earth. Those days are long gone, and those giants have vanished, but some 6,500 species of reptiles still thrive today. Crocodiles, snakes, lizards, and turtles are all reptiles. Most reptiles live on land, and most lay eggs. They are vertebrates, and, unlike any other animals, are covered in scales. They are cold-blooded, and regulate their body temperature by seeking or avoiding the sun's heat.
Galápagos Tortoise
Geochelone elephantophus
They are also the world's largest tortoises, with some specimens exceeding 5 feet (1.5 meters) in length and reaching 550 pounds (250 kilograms).
There are now only 11 types of giant tortoises left in the Galápagos, down from 15 when Darwin arrived. Hunted as food by pirates, whalers, and merchantmen during the 17th, 18th, and 19th centuries, more than 100,000 tortoises are estimated to have been killed off. Nonnative species such as feral pigs, dogs, cats, rats, goats, and cattle are a continuing threat to their food supply and eggs. Today, only about 15,000 remain.
The tortoises are now listed as endangered and have been strictly protected by the Ecuadorian government since 1970. Captive breeding efforts by the Charles Darwin Research Station are also having positive effects.
Galápagos tortoises lead an uncomplicated life, grazing on grass, leaves, and cactus, basking in the sun, and napping nearly 16 hours per day. A slow metabolism and large internal stores of water mean they can survive up to a year without eating or drinking.
Spanish sailors who discovered the archipelago in 1535 actually named it after the abundant tortoises; the Spanish word for tortoise is galápago.
Diet: Herbivore
Average lifespan in the wild: 100 years+
Size: 4 ft (1.2 m)
Weight: 475 lbs (215 kg)
Did you know? Today the 3,000 to 5,000 tortoises that live on Volcano Alcedo on Isabela Island are the largest group of giant tortoises in the Galápagos.
Protection status: Endangered
King Cobra
Ophiophagus hannah
It seems unfairly menacing that a snake that can literally "stand up" and look a full-grown person in the eye would also be among the most venomous on the planet, but that describes the famous king cobra.
King cobras can reach 18 feet (5.5 meters) in length, making them the longest of all venomous snakes. When confronted, they can raise up to one-third of their bodies straight off the ground and still move forward to attack. They will also flare out their iconic hoods and emit a bone-chilling hiss that sounds almost like a growling dog.
Their venom is not the most potent among venomous snakes, but the amount of neurotoxin they can deliver in a single bite—up to two-tenths of a fluid ounce (seven milliliters)—is enough to kill 20 people, or even an elephant. Fortunately, king cobras are shy and will avoid humans whenever possible, but they are fiercely aggressive when cornered.
King cobras live mainly in the rain forests and plains of India, southern China, and Southeast Asia, and their coloring can vary greatly from region to region. They are comfortable in the trees, on land, and in water, feeding mainly on other snakes, venomous and nonvenomous. They will also eat lizards, eggs, and small mammals.
They are the only snakes in the world that build nests for their eggs, which they guard ferociously until the hatchlings emerge.
King cobras may be best known as the species of choice for the snake charmers of South Asia. Although cobras can hear, they are actually deaf to ambient noises, sensing ground vibrations instead. The charmer's flute entices the cobra by its shape and movement, not by the music it emits.
Diet: Carnivore
Average lifespan in the wild: 20 years
Size: 13 ft (4 m)
Weight: Up to 20 lbs (9 kg)
Group name: Quiver
Did you know? Synthetic cobra venom is used in pain relievers and arthritis medication.
Frilled Lizard
Chlamydosaurus kingii
Undoubtedly, one of the quirkiest sights in nature is the gangly retreat of an Australian frilled lizard. When this unique creature feels threatened, it rises on its hind legs, opens its yellow-colored mouth, unfurls the colorful, pleated skin flap that encircles its head, and hisses. If an attacker is unintimidated by these antics, the lizard simply turns tail, mouth and frill open, and bolts, legs splaying left and right. It continues its deliberate run without stopping or looking back until it reaches the safety of a tree.
Frilled lizards, or "frillnecks," are members of the dragon family that live in the tropical and warm temperate forests and savanna woodlands of northern Australia. They spend most of their lives in the trees, but descend occasionally to feed on ants and small lizards. Other menu items include spiders, cicadas, termites, and small mammals.
They vary in color and size from region to region. On average, the larger adults reach about 3 feet (0.9 meters) from head to tail and weigh up to 1.1 pounds (0.5 kilograms).
Their main predators are birds of prey, larger lizards, snakes, dingoes and feral cats. They are currently not threatened or protected, but habitat reduction and predation in some areas, particularly by feral cats, is affecting their populations.
Females lay 8 to 23 tiny eggs in an underground nest, and hatchlings emerge fully independent and capable of hunting and utilizing their frill. Their lifespan in the wild is unknown, but specimens in captivity have lived 20 years.
Diet: Carnivore
Average lifespan in captivity: Up to 20 years
Size: 3 ft (0.9 m)
Weight: 1.1 lbs (0.5 kg)
Did you know? Besides defense, this lizard's colorful frill may be used to help regulate body temperature.
Gavial (Gharial)
Gavialis gangeticus
The crocodile-like gharial gets its name from the Hindi word ghara, a stout clay pot which resembles the bulbous growth on the nose of mature males. The growth, called a ghara, is used to attract mates and to generate bubbles, a facet of the mating ritual.
Gharials, also called gavials, are easily distinguished from crocodiles by their long, thin, almost tubular snout filled with small, razor-sharp teeth. This unique adaptation reduces drag in the water and allows them to quickly snap side-to-side to capture fish.
Gharials are among the largest of the crocodilians, with some males exceeding 20 feet (6 meters) in length. They are, unfortunately, also among the most endangered animals on the planet. Poaching for the skin trade, habitat reduction and accidental killings by fishermen have cut the wild population of this once-abundant predator to about 2,000. Males are also hunted in the belief that powder from its dried snout is an aphrodisiac.
Gharials live in the major rivers and waterways of the northern Indian subcontinent. They are likely extinct or nearly extinct in all of their range except India, where government efforts to preserve the species are having some success.
On land, gharials are unable to "high walk" like other crocodilians. They move about by sliding on their bellies. In water, however, webbed feet and a well developed, laterally flattened tail makes them the quickest and most agile of their class. They feed almost exclusively on fish, but have been known on occasion to take small mammals.
Diet: Carnivore
Average lifespan in the wild: 40 to 60 years
Size: 12.25 to 15.5 ft (3.6 to 4.5 m)
Weight: 2,200 lbs (977 kg)
Did you know? The gharial's scientific name, Gavialis gangeticus is based on a misspelling of the Hindi word ghariyal.
Protection status: Endangered
Green Anaconda
Eunectes murinus
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.
Diet: Carnivore
Average lifespan in the wild: 10 years
Size: 20 to 30 ft (6 to 9 m)
Weight: Up to 550 lbs (227 kg)
Group name: Bed or knot
Did you know? In mating, several competing males form a breeding ball around one female which can last up to four weeks.
Olive Ridley Sea Turtle
Lepidochelys olivacea
The olive ridley turtle is named for the generally greenish color of its skin and shell, or carapace. It is closely related to the Kemp’s ridley, with the primary distinction being that olive ridleys are found only in warmer waters, including the southern Atlantic, Pacific and Indian Oceans.
Olive and Kemp’s ridleys are the smallest of the sea turtles, weighing up to 100 pounds (45 kilograms) and reaching only about 2 feet (65 centimeters) in shell length. The olive ridley has a slightly smaller head and smaller shell than the Kemp’s.
These turtles are solitary, preferring the open ocean. They migrate hundreds or even thousands of miles (kilometers) every year, and come together as a group only once a year for the arribada, when females return to the beaches where they hatched and lumber onshore, sometimes in the thousands, to nest.
Olive ridleys have nesting sites all over the world, on tropical and subtropical beaches. During nesting, they use the wind and the tide to help them reach the beach. Females lay about 100 eggs, but may nest up to three times a year. The nesting season is from June to December.
The olive ridley is mostly carnivorous, feeding on such creatures as jellyfish, snails, crabs, and shrimp. They will occasionally eat algae and seaweed as well. Hatchlings, most of which perish before reaching the ocean, are preyed on by crabs, raccoons, pigs, snakes, and birds, among others. Adults are often taken by sharks.
Though the olive ridley is widely considered the most abundant of the marine turtles, by all estimates, it is in trouble. Rough estimates put the worldwide population of nesting females at about 800,000, but its numbers, particularly in the western Atlantic have declined precipitously. The United States lists the western Atlantic population of olive ridleys as endangered and all other populations as threatened.
Many governments have protections for olive ridleys, but still, eggs are taken and nesting females are slaughtered for their meat and skin. Fishing nets also take a large toll, frequently snagging and drowning these turtles.
Diet: Omnivore
Average lifespan in the wild: 50 years
Size: 2 to 2.5 ft (62 to 70 cm)
Weight: Up to 100 lbs (45 kg)
Did you know? Male olive ridleys can be distinguished from females by their tails, which stick out beyond their carapace.
Protection status: Endangered
Nile Crocodile
Crocodylus niloticus
The Nile crocodile has a somewhat deserved reputation as a vicious man-eater. The proximity of much of its habitat to people means run-ins are frequent. And its virtually indiscriminate diet means a villager washing clothes by a riverbank might look just as tasty as a migrating wildebeest. Firm numbers are sketchy, but estimates are that up to 200 people may die each year in the jaws of a Nile croc.
Africa's largest crocodilian, these primordial brutes reach a maximum size of about 20 feet (6 meters) and can weigh up to 1,650 pounds (730 kilograms). Average sizes, though, are more in the range of 16 feet (5 meters) and 500 pounds (225 kilograms). They live throughout sub-Saharan Africa, the Nile Basin, and Madagascar in rivers, freshwater marshes, and mangrove swamps.
The diet of the Nile crocodile is mainly fish, but it will attack almost anything unfortunate enough to cross its path, including zebras, small hippos, porcupines, birds, and other crocodiles. It will also scavenge carrion, and can eat up to half its body weight at a feeding.
One unusual characteristic of this fearsome predator is its caring nature as a parent. Where most reptiles lay their eggs and move on, mother and father Nile crocs ferociously guard their nests until the eggs hatch, and they will often roll the eggs gently in their mouths to help hatching babies emerge.
Hunted close to extinction in the 1940s through the 1960s, local and international protections have helped them rebound in most areas. In some regions, though, pollution, hunting, and habitat loss have severely depleted their numbers.
Diet: Carnivore
Average lifespan in the wild: 45 years (est.)
Size: 16 ft (5 m)
Weight: 500 lbs (225 kg)
Group name: Bask (on land) or float (in water)
Did you know? Mummified crocodiles and crocodile eggs have been discovered in Egyptian tombs.
Protection status: Endangered
Galápagos Tortoise
Geochelone elephantophus
They are also the world's largest tortoises, with some specimens exceeding 5 feet (1.5 meters) in length and reaching 550 pounds (250 kilograms).
There are now only 11 types of giant tortoises left in the Galápagos, down from 15 when Darwin arrived. Hunted as food by pirates, whalers, and merchantmen during the 17th, 18th, and 19th centuries, more than 100,000 tortoises are estimated to have been killed off. Nonnative species such as feral pigs, dogs, cats, rats, goats, and cattle are a continuing threat to their food supply and eggs. Today, only about 15,000 remain.
The tortoises are now listed as endangered and have been strictly protected by the Ecuadorian government since 1970. Captive breeding efforts by the Charles Darwin Research Station are also having positive effects.
Galápagos tortoises lead an uncomplicated life, grazing on grass, leaves, and cactus, basking in the sun, and napping nearly 16 hours per day. A slow metabolism and large internal stores of water mean they can survive up to a year without eating or drinking.
Spanish sailors who discovered the archipelago in 1535 actually named it after the abundant tortoises; the Spanish word for tortoise is galápago.
Diet: Herbivore
Average lifespan in the wild: 100 years+
Size: 4 ft (1.2 m)
Weight: 475 lbs (215 kg)
Did you know? Today the 3,000 to 5,000 tortoises that live on Volcano Alcedo on Isabela Island are the largest group of giant tortoises in the Galápagos.
Protection status: Endangered
King Cobra
Ophiophagus hannah
It seems unfairly menacing that a snake that can literally "stand up" and look a full-grown person in the eye would also be among the most venomous on the planet, but that describes the famous king cobra.
King cobras can reach 18 feet (5.5 meters) in length, making them the longest of all venomous snakes. When confronted, they can raise up to one-third of their bodies straight off the ground and still move forward to attack. They will also flare out their iconic hoods and emit a bone-chilling hiss that sounds almost like a growling dog.
Their venom is not the most potent among venomous snakes, but the amount of neurotoxin they can deliver in a single bite—up to two-tenths of a fluid ounce (seven milliliters)—is enough to kill 20 people, or even an elephant. Fortunately, king cobras are shy and will avoid humans whenever possible, but they are fiercely aggressive when cornered.
King cobras live mainly in the rain forests and plains of India, southern China, and Southeast Asia, and their coloring can vary greatly from region to region. They are comfortable in the trees, on land, and in water, feeding mainly on other snakes, venomous and nonvenomous. They will also eat lizards, eggs, and small mammals.
They are the only snakes in the world that build nests for their eggs, which they guard ferociously until the hatchlings emerge.
King cobras may be best known as the species of choice for the snake charmers of South Asia. Although cobras can hear, they are actually deaf to ambient noises, sensing ground vibrations instead. The charmer's flute entices the cobra by its shape and movement, not by the music it emits.
Diet: Carnivore
Average lifespan in the wild: 20 years
Size: 13 ft (4 m)
Weight: Up to 20 lbs (9 kg)
Group name: Quiver
Did you know? Synthetic cobra venom is used in pain relievers and arthritis medication.
Frilled Lizard
Chlamydosaurus kingii
Undoubtedly, one of the quirkiest sights in nature is the gangly retreat of an Australian frilled lizard. When this unique creature feels threatened, it rises on its hind legs, opens its yellow-colored mouth, unfurls the colorful, pleated skin flap that encircles its head, and hisses. If an attacker is unintimidated by these antics, the lizard simply turns tail, mouth and frill open, and bolts, legs splaying left and right. It continues its deliberate run without stopping or looking back until it reaches the safety of a tree.
Frilled lizards, or "frillnecks," are members of the dragon family that live in the tropical and warm temperate forests and savanna woodlands of northern Australia. They spend most of their lives in the trees, but descend occasionally to feed on ants and small lizards. Other menu items include spiders, cicadas, termites, and small mammals.
They vary in color and size from region to region. On average, the larger adults reach about 3 feet (0.9 meters) from head to tail and weigh up to 1.1 pounds (0.5 kilograms).
Their main predators are birds of prey, larger lizards, snakes, dingoes and feral cats. They are currently not threatened or protected, but habitat reduction and predation in some areas, particularly by feral cats, is affecting their populations.
Females lay 8 to 23 tiny eggs in an underground nest, and hatchlings emerge fully independent and capable of hunting and utilizing their frill. Their lifespan in the wild is unknown, but specimens in captivity have lived 20 years.
Diet: Carnivore
Average lifespan in captivity: Up to 20 years
Size: 3 ft (0.9 m)
Weight: 1.1 lbs (0.5 kg)
Did you know? Besides defense, this lizard's colorful frill may be used to help regulate body temperature.
Gavial (Gharial)
Gavialis gangeticus
The crocodile-like gharial gets its name from the Hindi word ghara, a stout clay pot which resembles the bulbous growth on the nose of mature males. The growth, called a ghara, is used to attract mates and to generate bubbles, a facet of the mating ritual.
Gharials, also called gavials, are easily distinguished from crocodiles by their long, thin, almost tubular snout filled with small, razor-sharp teeth. This unique adaptation reduces drag in the water and allows them to quickly snap side-to-side to capture fish.
Gharials are among the largest of the crocodilians, with some males exceeding 20 feet (6 meters) in length. They are, unfortunately, also among the most endangered animals on the planet. Poaching for the skin trade, habitat reduction and accidental killings by fishermen have cut the wild population of this once-abundant predator to about 2,000. Males are also hunted in the belief that powder from its dried snout is an aphrodisiac.
Gharials live in the major rivers and waterways of the northern Indian subcontinent. They are likely extinct or nearly extinct in all of their range except India, where government efforts to preserve the species are having some success.
On land, gharials are unable to "high walk" like other crocodilians. They move about by sliding on their bellies. In water, however, webbed feet and a well developed, laterally flattened tail makes them the quickest and most agile of their class. They feed almost exclusively on fish, but have been known on occasion to take small mammals.
Diet: Carnivore
Average lifespan in the wild: 40 to 60 years
Size: 12.25 to 15.5 ft (3.6 to 4.5 m)
Weight: 2,200 lbs (977 kg)
Did you know? The gharial's scientific name, Gavialis gangeticus is based on a misspelling of the Hindi word ghariyal.
Protection status: Endangered
Green Anaconda
Eunectes murinus
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.
Diet: Carnivore
Average lifespan in the wild: 10 years
Size: 20 to 30 ft (6 to 9 m)
Weight: Up to 550 lbs (227 kg)
Group name: Bed or knot
Did you know? In mating, several competing males form a breeding ball around one female which can last up to four weeks.
Olive Ridley Sea Turtle
Lepidochelys olivacea
The olive ridley turtle is named for the generally greenish color of its skin and shell, or carapace. It is closely related to the Kemp’s ridley, with the primary distinction being that olive ridleys are found only in warmer waters, including the southern Atlantic, Pacific and Indian Oceans.
Olive and Kemp’s ridleys are the smallest of the sea turtles, weighing up to 100 pounds (45 kilograms) and reaching only about 2 feet (65 centimeters) in shell length. The olive ridley has a slightly smaller head and smaller shell than the Kemp’s.
These turtles are solitary, preferring the open ocean. They migrate hundreds or even thousands of miles (kilometers) every year, and come together as a group only once a year for the arribada, when females return to the beaches where they hatched and lumber onshore, sometimes in the thousands, to nest.
Olive ridleys have nesting sites all over the world, on tropical and subtropical beaches. During nesting, they use the wind and the tide to help them reach the beach. Females lay about 100 eggs, but may nest up to three times a year. The nesting season is from June to December.
The olive ridley is mostly carnivorous, feeding on such creatures as jellyfish, snails, crabs, and shrimp. They will occasionally eat algae and seaweed as well. Hatchlings, most of which perish before reaching the ocean, are preyed on by crabs, raccoons, pigs, snakes, and birds, among others. Adults are often taken by sharks.
Though the olive ridley is widely considered the most abundant of the marine turtles, by all estimates, it is in trouble. Rough estimates put the worldwide population of nesting females at about 800,000, but its numbers, particularly in the western Atlantic have declined precipitously. The United States lists the western Atlantic population of olive ridleys as endangered and all other populations as threatened.
Many governments have protections for olive ridleys, but still, eggs are taken and nesting females are slaughtered for their meat and skin. Fishing nets also take a large toll, frequently snagging and drowning these turtles.
Diet: Omnivore
Average lifespan in the wild: 50 years
Size: 2 to 2.5 ft (62 to 70 cm)
Weight: Up to 100 lbs (45 kg)
Did you know? Male olive ridleys can be distinguished from females by their tails, which stick out beyond their carapace.
Protection status: Endangered
Nile Crocodile
Crocodylus niloticus
The Nile crocodile has a somewhat deserved reputation as a vicious man-eater. The proximity of much of its habitat to people means run-ins are frequent. And its virtually indiscriminate diet means a villager washing clothes by a riverbank might look just as tasty as a migrating wildebeest. Firm numbers are sketchy, but estimates are that up to 200 people may die each year in the jaws of a Nile croc.
Africa's largest crocodilian, these primordial brutes reach a maximum size of about 20 feet (6 meters) and can weigh up to 1,650 pounds (730 kilograms). Average sizes, though, are more in the range of 16 feet (5 meters) and 500 pounds (225 kilograms). They live throughout sub-Saharan Africa, the Nile Basin, and Madagascar in rivers, freshwater marshes, and mangrove swamps.
The diet of the Nile crocodile is mainly fish, but it will attack almost anything unfortunate enough to cross its path, including zebras, small hippos, porcupines, birds, and other crocodiles. It will also scavenge carrion, and can eat up to half its body weight at a feeding.
One unusual characteristic of this fearsome predator is its caring nature as a parent. Where most reptiles lay their eggs and move on, mother and father Nile crocs ferociously guard their nests until the eggs hatch, and they will often roll the eggs gently in their mouths to help hatching babies emerge.
Hunted close to extinction in the 1940s through the 1960s, local and international protections have helped them rebound in most areas. In some regions, though, pollution, hunting, and habitat loss have severely depleted their numbers.
Diet: Carnivore
Average lifespan in the wild: 45 years (est.)
Size: 16 ft (5 m)
Weight: 500 lbs (225 kg)
Group name: Bask (on land) or float (in water)
Did you know? Mummified crocodiles and crocodile eggs have been discovered in Egyptian tombs.
Protection status: Endangered