15 Examples of the Most Epic Metamorphoses from Youth to Adult

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iStock

We’re all familiar with the most dramatic metamorphosizers of the animal kingdom: butterflies. They go from a tiny egg to an awkward wiggling caterpillar to mysterious pupa to a delicate, colorful winged creature. However, there are many other animals besides butterflies that undergo dramatic transformations from youth to adult. Here are 15 of the most epic metamorphoses seen in nature.

1. LADYBUGS (COCCINELLIDAE)

What’s black, white, and red all over? Many ladybugs are—but only in their final stage of life. Turns out these little beetles undergo one of the most epic metamorphoses in the animal kingdom: For most species, after adult female ladybugs mate, they lay a clutch of tiny yellow eggs right in the middle of an aphid colony, usually on the underside of a leaf. Eggs hatch in a week, revealing spiky black worm-like larvae that readily gobble up the aphids around them. When a larva is fully grown, it changes into a blob-like yellow pupa. Finally, the black, white and red (or sometimes yellow or orange) insect appears.

2. MAYFLY (EPHEMEROPTERA)

Mayflies, the less-elegant cousins of dragonflies and damselflies, have one of the most unique metamorphoses of all insects. Most insects’ life stages move from egg to nymph to pupa to adult, but mayflies do not have a pupa stage. Instead, it is the only type of insect to undergo a subimago stage, meaning it’s almost an adult in the sense it grows wings … but cannot fly long distances and isn’t yet sexually mature. The mayfly’s final life stage, the fully flighted and sexually mature imago or adult, is extremely short, lasting just a few hours to a few days.

3. PEACOCK SPIDER (MARATUS)

Left: Jurgen Otto, Flickr // CC BY-NC-ND 2.0; Right: Jurgen Otto, Flickr // CC BY-NC-ND 2.0

Peacock spiders are tiny, venomous, and beautiful (especially the colorfully rumped males) arthopods native to Australia. Male peacock spiders are so beautiful, in fact, it’s hard to believe that, like all spiders, they go through some not-so-glamorous life stages: egg, egg sac, spiderling, adult. When male peacock spiders reach sexual maturity they try to seduce less-colorful female peacock spiders by performing a showy dance.

4. NUDIBRANCH (NUDIBRANCHIA)

While adult nudibranchs are essentially colorful and ornate blobs of the sea, they don’t start out that way. In fact, after hatching, nudibranch larvae are tiny, plain-looking and have small snail-like shells. Over the course of two months they morph from this plain stage into adults, along the way getting larger and more colorful, losing their shells, and growing gills and feelers, called rhinophores.

5. CROWN OF THORNS STARFISH (ACANTHASTER PLANCI)

Another sea creature that looks completely different as an adult than a juvenile is the crown of thorns starfish. When looking at an adult, it’s easy to see where this creature gets its name: It’s completely covered with dangerous-looking sharp spikes. But after hatching, it looks like not much more than a translucent, floating blob. Over time it grows arms, and later, spikes, then fixes itself to rocks where it feeds on coral.

6. IMMORTAL JELLYFISH (TURRITOPSIS DOHRNII)

The secret to a long and prosperous life, it turns out, is to be a jellyfish. The aptly named immortal jellyfish begins life as an egg, like all other jellies. It then enters the free-swimming larva stage, then settles down into a polyp on the ocean floor, and then finally morphs into a sexually mature jellyfish. Unlike most other jellies, an immortal jellyfish is capable of reverting back into the polyp stage at any time it faces environmental stress, attacks by predators, sickness or old age—essentially being reborn as a young jelly.

7. FLATFISH (PLEURONECTIFORMES)

Think of Pablo Picasso’s most asymmetrically painted human face, stick it onto a fish, and there you have a flatfish. These fish, which include flounder and sole among other species, begin life inside tiny eggs that float up to the surface of the sea. For a few weeks, a larval flatfish swims upright and looks just like a typical baby fish. But after a few weeks its skull bones shift and one eye migrates to the opposite side of its face, forcing the now-lopsided fish to swim sideways. Eventually, when its facial features all move to one side of its face, it changes color and moves to live on the bottom of the sea, its blind side facing down.

8. EASTERN HELLBENDER (CRYPTOBRANCHUS ALLEGANIENSIS)

Left: Pete and Noe Woods, Flickr // CC BY 2.0; Right: Projosh More, Flickr // CC BY 2.0

Also called the snot otter and devil dog, the eastern hellbender is a giant type of salamander not exactly known for being beautiful in its adult form. Slippery, wrinkly and the color of mud, they’re right at home at the bottom of rivers, where they can live up to 50 years. Like all salamanders, hellbenders begin as eggs. From their eggs they hatch, coming into the world small and adorable. As time passes, they grow larger and less cute.

9. CHALAZODES BUBBLE NEST FROG (RAORCHESTES CHALAZODES)

Don’t let this lime-green frog’s bright and cheery looks fool you: It lives in only one tiny area in India and is critically endangered, threatened most by an ever-shrinking habitat. These creatures were once believed to lay eggs that developed into tadpoles on pond surfaces like many other frogs. But in 2014, it was discovered that they had a different reproductive strategy: The frogs crawl into a living bamboo shoot that has a hole in it (probably created by insects or rodents) and lay their eggs there. The creatures skip the tadpole stage entirely, hatching as froglets. Because they don't have a tadpole stage, the species doesn't require water to lay its eggs.

10. MIMIC POISON DART FROG (RANITOMEYA IMITATOR)

Mattias Starkenberg, Wikimedia Commons // CC BY-SA 3.0

Covered in bright hues spotted, striped, banded, and blotched with contrasting black, the poison dart frog is one of the most striking-looking of all amphibians. Yet they don’t start out that way. After hatching, young mimic poison dart frogs are looked after by their mother, who lays a clutch of unfertilized feeder eggs to provide them with some nourishment (and, at least for some species of poison dart frog, toxicity). Tadpoles are brown and black, growing more colorful with age until they reach their fantastic adult form.

11. KEA (NESTOR NOTABILIS)

The kea is a large, vulnerable species of parrot native to New Zealand, with green and blue feathers on its back and brown and orange feathers on its underside. While adult keas appear majestic and beautiful, they don’t start out that way. Baby keas retain an alien-like, sparse white hairdo for several months after hatching. Keas are considered a very intelligent species, observed working together and using tools.

12. LAYSAN ALBATROSS (PHOEBASTRIA IMMUTABILIS)

Laysan albatrosses are another species of bird where the babies are very little like their parents. But unlike baby keas, baby Laysan albatrosses hatch as adorable fuzzy gray blobs. As they grow older, the babies slowly grow adult feathers and lose their baby feathers. This leaves them with unique hairdos that sometimes make them look like human celebrities. Ringo Starr, anyone?

13. FLAMINGO (PHOENICOPTERUS)

Left: Getty Images // Right: iStock

Unlike keas and albatrosses, baby flamingoes look a lot like their parents, except they’re missing something: color. Flamingo chicks hatch with gray and/or white feathers, over time taking on the same pink hue as their parents, which becomes more intense over time. Why? Well, you are what you eat, and flamingoes eat shrimp and algae rich in carotenoids, the same pigments that cause shrimp to turn pink when cooked.

14. VIRGINIA OPOSSUM (DIDELPHIS VIRGINIANA)

Virginia opossums are scavengers, eating carrion and rotting vegetation, and that helps keep the environment clean. Virginia opossums are native to North America, where they’re the continent’s only living marsupials. These opossums have pouches for carrying their babies, just like kangaroos. Also like kangaroos they give birth to large numbers of navy-bean-size babies, which grow inside their pouches. When they’re born, they look more like pink jellybeans than animals. Over the course of three to five months, they mature, growing fur, sharp teeth and long tails.

15. GIANT PANDA (AILUROPODA MELANOLEUCA)

Getty Images

Giant pandas are called giant pandas for a reason: They’re enormous in size, weighing up to 250 pounds. But these bamboo-munching bears don’t start out that way. When born, giant panda cubs weigh just 90 to 130 grams (about as much as a small apple). Besides being way smaller in size, baby pandas are also quite sparsely furred—and so they look very different than what they will as fuzzy black-and-white adults.

20 Black-and-White Facts About Penguins

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iStock/fieldwork

Who is a penguin's favorite family member? Aunt Arctica! 

We kid! But seven of the 17 species of penguins can be found on the southernmost continent. Here are 20 more fun facts about these adorable tuxedoed birds. 

1. All 17 species of penguins are found exclusively in the Southern Hemisphere.

A group of penguins on an iceberg.
iStock/axily

2. Emperor Penguins are the tallest species, standing nearly 4 feet tall. The smallest is the Little Blue Penguin, which is only about 16 inches.

Three emperor penguins
iStock/Fabiano_Teixeira

3. The fastest species is the Gentoo Penguin, which can reach swimming speeds up to 22 mph.

A gentoo penguin swimming underwater
iStock/chameleonseye

4. A penguin's striking coloring is a matter of camouflage; from above, its black back blends into the murky depths of the ocean. From below, its white belly is hidden against the bright surface.

Penguins swimming in the ocean
iStock/USO

5. Fossils place the earliest penguin relative at some 60 million years ago, meaning an ancestor of the birds we see today survived the mass extinction of the dinosaurs.

Emperor penguins with chicks
iStock/vladsilver

6. Penguins ingest a lot of seawater while hunting for fish, but a special gland behind their eyes—the supraorbital gland—filters out the saltwater from their blood stream. Penguins excrete it through their beaks, or by sneezing.

Penguin swimming in the ocean
iStock/Musat

7. Unlike most birds—which lose and replace a few feathers at a time—penguins molt all at once, spending two or three weeks land-bound as they undergo what is called the catastrophic molt.

Gentoo penguin chick molting
iStock/ChristianWilkinson

8. All but two species of penguins breed in large colonies of up to one thousand birds.

A colony of king penguins
iStock/DurkTalsma

9. It varies by species, but many penguins will mate with the same member of the opposite sex season after season.

Two chinstrap penguins
iStock/Legacy-Images

10. Similarly, most species are also loyal to their exact nesting site, often returning to the same rookery in which they were born.

Magellanic penguin nesting in the ground
iStock/JeremyRichards

11. Some species create nests for their eggs out of pebbles and loose feathers. Emperor Penguins are an exception: They incubate a single egg each breeding season on the top of their feet. Under a loose fold of skin is a featherless area with a concentration of blood vessels that keeps the egg warm.

Penguin eggs
iStock/Buenaventuramariano

12. In some species, it is the male penguin which incubates the eggs while females leave to hunt for weeks at a time. Because of this, pudgy males—with enough fat storage to survive weeks without eating—are most desirable.

A group of emperor penguins and chick
iStock/vladsilver

13. Penguin parents—both male and female—care for their young for several months until the chicks are strong enough to hunt for food on their own.

Penguin chick and parent on a nest
iStock/golnyk

14. If a female Emperor Penguin's baby dies, she will often "kidnap" an unrelated chick.

Three emperor penguin chicks
iStock/AntAntarctic

15. Despite their lack of visible ears, penguins have excellent hearing and rely on distinct calls to identify their mates when returning to the crowded breeding grounds.

Gentoo penguins
iStock/Goddard_Photography

16. The first published account of penguins comes from Antonio Pigafetta, who was aboard Ferdinand Magellan's first circumnavigation of the globe in 1520. They spotted the animals near what was probably Punta Tombo in Argentina. (He called them "strange geese.")

A group of magellanic penguins on the seacoast
iStock/encrier

17. An earlier, anonymous diary entry from Vasco da Gama's 1497 voyage around the Cape of Good Hope makes mention of flightless birds as large as ducks.

A cape penguin in South Africa
iStock/ziggy_mars

18. Because they aren't used to danger from animals on solid ground, wild penguins exhibit no particular fear of human tourists.

Man videotaping a penguin in Antarctica
iStock/Bkamprath

19. Unlike most sea mammals—which rely on blubber to stay warm—penguins survive because their feathers trap a layer of warm air next to the skin that serves as insulation, especially when they start generating muscular heat by swimming around.

Penguin swimming in the ocean
iStock/Musat

20. In the 16th century, the word penguin actually referred to great auks (scientific name: Pinguinus impennis), a now-extinct species that inhabited the seas around eastern Canada. When explorers traveled to the Southern Hemisphere, they saw black and white birds that resembled auks, and called them penguins.

This story was first published in 2017.

10 Colorful Facts About Cassowaries

iStock/BirdImages
iStock/BirdImages

All birds are living dinosaurs, but the dagger-clawed cassowary especially looks the part. Even wildlife biologists call cassowaries the world's most dangerous bird—and yes, it has been known to kill people. Here’s everything you need to know about the majestic and terrifying beast.

1. The southern cassowary is Earth's second-heaviest bird.

Scientists recognize three living species of cassowary—all of which live in New Guinea, northeastern Australia, and nearby islands. The dwarf cassowary is the smallest, with an average height of around 3 feet. The northern cassowary, an orange-throated behemoth, can stand nearly 5 feet tall. The southern cassowary is bigger than both at 5 foot 6 inches tall. The only two birds that grow taller are ostriches and emus. Adult southern cassowary females can weigh up to 157 pounds, and males 121 pounds, making them the second-heaviest birds on the planet behind ostriches.

2. Cassowaries have dangerous feet.

In the southern cassowary's Australian range, you might come across warning signs that read “Be Cass-o-wary.” Heed this advice. Normally, cassowaries are shy and reclusive, but they can become aggressive when threatened and strike back with powerful head-butts and pecks. Their most dangerous weapon is the razor-sharp claw on the middle toe of each foot, which, in southern cassowaries, grows to be 5 inches long. The birds deliver a series of downward kicks that have been known to break bones and cause fatal lacerations. 

3. Rearing cassowary chicks is the father's job.

Female cassowaries breed with several partners. After laying her eggs, she abandons them, at which point the males take over and incubates the eggs for at least 50 days. The fathers never leave the nest, not even to eat or drink. Once the eggs hatch, males spend the next nine months raising and defending the chicks. Males also teach the chicks how to forage so they can fend for themselves.

4. Cassowaries are surprisingly good jumpers.

What’s scarier than a 150-pound modern dinosaur with killer claws? One that can leap 7 feet off the ground. To get the most out of those toe daggers, cassowaries will sometimes jump feet-first at an attacker, with the claws slashing downward in midair. They’re also great swimmers and sprinters with a top running speed of 30 miles per hour.

5. Cassowaries have a spike hidden on each wing.

Cassowaries are closely related to emus and more distantly related to ostriches, rheas, and kiwis. All of these birds, known as ratites, are flightless. Cassowaries have small vestigial wings tipped with a small claw that probably serves no purpose.

6. Cassowaries are frugivores that also eat their own poop.

Wild cassowaries dine mainly on fruits and berries that fall to the ground in the rainforests they call home. A typical southern cassowary can eat up to 11 pounds of fruit a day, along with plenty of fungi and the occasional dead animal for some extra protein.

Cassowaries also hunt rodents, snails, and lizards. Poop is yet another item on the menu. Cassowary poop usually contains half-digested fruit, which still has plenty of nutritional value, so the birds devour each other’s droppings as well as their own. 

7. The function of their odd crests, or casques, is a mystery. 

Cassowaries sport royal-blue necks and shaggy black feathers, but their most distinctive feature is the helmet-like casque that sits above the eyes. The bony protrusion is covered with a sheath of keratin (the material that makes up your fingernails), and it begins to develop when the bird is around 2 years old. Scientists have long speculated, sometimes wildly, about its purpose. One theory is that casques help cassowaries push aside forest underbrush. The casques might also be used to attract the opposite sex.

A more interesting hypothesis involves how these birds communicate. Cassowaries emit very deep bellows—the lowest bird calls known to humans. Perhaps their casques amplify and broadcast these sounds by acting as a resonance chamber. Certain crested dinosaurs (like Parasaurolophus of Jurassic Park fame) may have produced calls the same way.

8. Cassowaries can live for decades (at least in zoos).

Naturalists don’t know how long a wild cassowary can expect to live. A few southern cassowaries have reached their 40th birthdays in captivity. In zoos, northern cassowaries can top that figure—one reached the age of 48 and another may have been as old as 61. The average lifespan for captive dwarf cassowaries is about 26 years.

9. Cassowaries have strange genitalia.

Both sexes have a pseudo-penis that isn’t connected to any of their internal reproductive organs. When cassowaries mate, the male ejaculates through his cloaca, an orifice at the base of the pseudo-penis. When they aren’t mating, males' pseudo-penis is turned inside out and retracted.

Such peculiar anatomy has given the cassowary a unique place in New Guinean culture and folklore. For example, the native Mianmin people tell stories about a human woman with a penis who somehow transformed into a cassowary. Another indigenous group, the Umeda, put on a regular ceremony called “ida.” A big event that lasts for two days and nights, the ritual involves a fertility dance which calls for two male dancers who represent a pair of cassowaries. Each player is given a heavy mask and is coated with charcoal from head to toe.

10. At least two unfortunate humans have been killed by cassowaries. 

To date, there have been only two verified reports of a cassowary taking human life. In April 1926, a cassowary fatally charged 16-year-old farmer Phillip McLean in north Queensland, Australia. More recently, a 75-year-old Florida man was killed by a cassowary he had kept as a pet at his exotic bird farm.

In 1999, Queensland Parks and Wildlife ranger Christopher P. Kofron analyzed 150 documented cassowary-on-human attacks. Twenty-two percent of attacks resulted from the bird defending itself, its eggs, or its chicks, 5 percent were triggered by somebody getting too close to the cassowary’s food, and 73 percent involved a cassowary that associated people with free meals. Many cassowaries in Australia had lost their natural shyness around humans thanks to people feeding them bananas and watermelon. Today, feeding a wild one is against the law, but the practice continues.

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