This is the smallest frog in the world.  Not only is Paedophryne amauensis the smallest frog, it is also the smallest amphibian.  And, not only is it the smallest amphibian, this miniscule frog also happens to be the world’s smallest vertebrate.

Measuring in at .3 inches long (7.7 mm), this little froggie was discovered in 2009, but wasn’t formally described until 2012.  Because it is so small, researchers didn’t even see it at first.  They kept hearing an unknown animal call, pinpointed the location that the noise was coming from, and picked up a handful of leaf litter. It was only then that they saw the small frog hopping around in the plastic bag that they had used.  

Paedophryne amauensis lives in the forests of Papua New Guinea.  They don’t hatch as tadpoles, instead crawling out of their eggs as miniature adults.  The tiny frog can also hop almost a foot in distance, which may not sound like much, but is actually thirty times their own body length.

This is the tragic tale of an odd amphibian, briefly glimpsed and studied, before vanishing into the wilds of Australia, never to be seen again.  The southern gastric brooding frog, which was discovered in 1972, formally described in 1973, and went extinct in 1983.  Its sister species, the northern gastric brooding frog, was found in 1984, but it to disappeared just a year later in 1985.

The gastric brooding frog was an extraordinary animal.  When the eggs were laid and fertilized, the female frog would take them in her mouth and swallow them, not to eat them, but to let them hatch.  She stopped producing digestive acids, eating nothing until the eggs hatch and grow, not into tadpoles, but miniature frogs.  These froglets would then emerge through her mouth into the world, where they would continue the cycle of eating eggs and regurgitating frogs.

Despite it being considered extinct, scientists are certain that they can bring the gastric brooding frog back.  Already, an egg containing an embryo was created in a lab.  This was done by taking DNA from a frozen gastric brooding frog and inserting it into the egg of a barred frog.  The cells did stop dividing after a while, but those working on the project believe that they will eventually get the procedure right, and give the world another glimpse of the incredible gastric brooding frog.

The crucifix toad, which is also called the holy cross toad, gets its name from the marking on its back.  The red and black dots create a shape similar to that of a cross against a bright yellow background act as a warning to potential predators that the toad is toxic.

This quarter sized amphibian makes its home in Australia, where it stays underground for nearly all of its life, only coming out after it rains to breed.  Since the rain creates temporary ponds, the entire development of crucifix toads, from egg to tadpole to adult hood, happens very quickly, sometimes in just five weeks.

Perhaps the most interesting thing about the crucifix toad is the ‘glue’ it secretes from its skin.  Scientists aren’t sure exactly what the glue is for.  Some think that it might be used to trap insects that land on the toad, so that it can eat them later, while some think that males use it to attach themselves to females during breeding.  What they do know for sure is that it is an extremely strong adhesive, and stays sticky even when it gets wet.  This has led to the crucifix toad is being researched in an attempt to create a better medical adhesive.

Do you know how many Rabb’s fringe-limbed treefrogs there are?  The answer is one.  In 2006, herpetologists (reptile and amphibian experts) rushed into Panama with the intent of saving the local frogs, which were being wiped out thanks to a fungus.  Several dozen frogs and tadpoles were brought back, and while they thrived in captivity, they never produced any offspring, and gradually died off.  Eventually Toughie (a rather fitting name) was the last one left, and the Rabb’s fringe-limbed treefrog was listed as extinct in the wild.

While Toughie resides in the Atlanta Botanical Gardens, his native home is the in cloud forests of Panama. Here, Rabb’s fringe-limbed treefrogs would spend their lives in the canopy, hiding during the day and coming out at night to search for insects amongst the leaves.  Another thing these frogs would search for were mates.  

Reproductively speaking, Ecnomiohyla rabborum were similar to other tree dwelling frogs in many ways.  Males competed for breeding rights with females, who would then lay their eggs in small pools of water that had collected in various tree holes, and would then leave.  The males would stay behind, watching the eggs and tadpoles.  It is here that Rabb’s fringe-limbed treefrog differs from other treefrogs.  Instead of constantly searching for small bugs to bring back for the tadpoles to eat, the males of this species would simply dunk their rear ends into the tadpole’s oasis and let them eat bits of skin off of his back, making this frog the only one on the planet to feed its young this way.  This unusual feeding method wasn’t harmful to the males at all, though it certainly puts a new meaning to the saying ‘it’s no skin off my back’.

Living high in the treetops certainly seems exciting, but what would you do if you slipped and fell? Rabb’s fringe-limbed treefrog has a solution; flight.  Well, it’s not really flying, but when a frog leaps from a branch and glides 30 feet (that about 100 times the length of their own body) to safety using only the webbing between their toes, it’s a little difficult not to be impressed.  

Four eyed frogs don’t actually have four eyes.  What they do have is two poison glands on their back that merely look like eyes. If something comes along to eat a four eyed frog, it inflates itself to look bigger and raises its rear end at the predator.  This is confuses most animals, since they can’t tell the front from the back anymore, so they usually end up leaving.  If this doesn’t work, the Columbian four eyed frog straightens out its back legs to reveal the vibrant orange coloration in an attempt to startle the predator.  And if the hungry creature decides to take a bite out of the frog, it ends up with a mouthful of poison.

The Columbian four eyed frog doesn’t just live in Columbia.  This small amphibian’s habitat stretches across the entire northern coast of the South American continent, as well as a few nearby islands.  Columbian four eyed frogs thrive in this warm climate, and as a result is a very common species.

While warmth is important for an amphibian’s survival, water is absolutely crucial.  Unfortunately for the Columbian four eyed frog, the grasslands and savannahs that they live in have dry seasons.  During this time, the frogs will stick to tiny pools, puddles, and any other source of water that they can find.  If it can’t find moisture, the Columbian four eyed frog will burrow underground and hide out until the wet season comes around.

The Mexican mushroom-tongue salamander lives not only in Mexico, but in Guatemala, Belize, and the Honduras as well.  Other than its fabulous name, the Mexican mushroom-tongue salamander isn’t anything special compared to the other members of its genus.

However, that does not mean that that the Bolitoglossa genus is ordinary.  There are 117 species in this genus and each and every one of them is incredible.  None of them have lungs, instead absorbing oxygen directly through their skin.  They are the only salamanders (with the exception of a cave dweller) that have webbed feet.  Bolitoglossa salamanders also have prehensile tails that they use to navigate the branches of the rainforests that they live in.

These salamanders come in a variety of sizes, ranging from just under two inches in length to nearly 8 inches long.  Here is a picture of the smallest species (B. dolfleini) sitting on the largest species (B. rufescens) of the genus.

All of them live in Central and South America, and the Bolitoglossa genus is famous for having the only known salamander hybrid in the world.  Additionally, many of these salamanders have sensory tentacles that look exactly like a mustache, making them some of the most dapper amphibians around.

What looks like a lizard, acts like a lizard, but isn’t a lizard?  The answer to that question is the northern tuatara, one of the oldest and most unusual reptiles on the planet.

The tuatara is one of the oldest reptiles on the planet in more ways than one.  Tuataras are ancient creatures; the only surviving members of the order Rhynchocephalia.  They have amphibian-like brains, fish-like spines, and the most primitive heart and lungs of any reptile.  They also have extremely long lifespans; it can take the tuatara 20 years to reach sexual maturity, five years to develop and lay an egg (the slowest reproduction of any reptile), and 35 years to get to their maximum length of two feet.  There is a captive tuatara that is over 100 years old and still able to reproduce, leading some scientists to think that these reptiles might have a lifespan of a whopping 200 years.

Tuataras live exclusively in New Zealand.  Until the introduction of invasive species such as rats and cats, the tuatara had no natural predators, but that doesn’t mean it can’t defend itself.  This reptile has armored spines all along its back and tail, and like a lizard, has the ability to break off said tail if it is grabbed.  Tuataras also have a nasty bite that they will direct at anything that gets too close, as well as the tendency to keep their mouth clamped shut on whatever it has sunk its teeth into.

Even though they evolved with no predators, the tuatara still prefers to come out at night.  With the exception of the young, who are active during the day to avoid the cannibalistic adults, tuataras are almost entirely nocturnal.  This is because these reptiles need cooler temperatures to survive.  Anything over 82° F can be fatal, so during the day, tuataras hide out in burrows that they have dug themselves or borrowed from nesting sea birds.  Once night falls, the tuatara goes on the hunt, searching for bugs, frogs, lizards, and eggs.  When dawn approaches, the tuatara detects the ultraviolet rays of the sun using its third eye, a sensory organ on the top of its head that can tell dark from light, and makes its way back to its shelter to rest until it is time to hunt again.

The hoatzin stinks. In fact, it stinks so much that it is sometimes called the stinkbird.  The reason for this malodorous nickname comes from the bird’s diet: the hoatzin is the only bird on the planet to leaves all day, every day, causing it to constantly smell like manure.  Leaves are meant to be eaten by animals like cows, not by birds.  

This folivorous diet is not the only thing the hoatzin has in common with cows.  These birds have an enlarged crop to help digest the leaves that can be compared to a bovine’s chambered stomach.  The hoatzin is also a social creature, usually living in flocks of about a dozen or so.

Other than its unusual diet, the hoatzin has another trick up its sleeve (or wing, in this case). Hoatzins hatch with claws, not on their feet, but on their wings.  This seems to be an evolutionary throwback, assisting the hatchlings in climbing up trees while their feathers are growing in.

Hoatzins live in the Amazon rainforest, preferring marshy areas with lots of water (the babies can also swim to evade predators, along with climbing trees).  Despite the fact that they are poor fliers, and sit around most of the time, the hoatzin is not hunted by humans, who are put off by the foul smell and the poor quality of the flesh.  The main threat to the survival of these unique birds (scientists still aren’t sure what they’re related to) is the deforestation of their habitat.

The Galapagos Islands; home to all manner of strange animals, like giant tortoises, marine iguanas, finches, and penguins.  Yes, penguins.  The Galapagos penguin is the only species of penguin that lives north of the equator and is the rarest in the world.

Penguins are built for cold weather, so in order to survive in a tropical paradise, the Galapagos penguin had to makes some changes.  Eggs are laid in shady spots, and the young are born with light feathers to protect them from the sun (darker colors absorb heat, but lighter colors reflect it), while the adults spend a lot of time in the water to cool down.  

Galapagos penguins have also developed a unique method of thermoregulation.  Whenever the penguins are on land and in the sun, they’ll hunch forward and hold their wings out to keep their feet shady.  This is because heat is released through the blood vessels in the feet, and keeping their feet out of the sun means that they can cool off faster.  

Even though these birds live in a fairly warm location, the cold is still extremely important to them. The Cromwell Current keeps the water where the penguins live significantly colder than the rest of the Pacific Ocean. Cooler water is good, because it means more food.  The Galapagos penguin is so dependent on this chilly current that in El Niño seasons, they don’t breed, because the warmer waters wouldn’t support enough fish to feed chicks.  That doesn’t matter to this penguin, though.  Galapagos penguins mate for life, so even if they don’t have a chick, they’ll still have each other.  

What if I told you that there is an animal that can be found in Europe, Asia, and the Americas, is carnivorous, has 15 sets of legs, and is probably IN YOUR HOUSE RIGHT NOW AND IT LOOKS LIKE THIS!!

Although it may look like some sort of alien monster, it’s actually the humble house centipede. They’re relatively harmless (most of these arthropods couldn’t hurt you if they tried due to their tiny teeth) and eat the bugs you should really be worrying about (aka cockroaches, termites, silverfish, and bedbugs).  House centipedes don’t carry disease, don’t destroy your property, and try to stay out of people’s way.  

The body of a house centipede is only about an inch long, but thanks to those ridiculously long legs and antennae, it can look much bigger.  It also spends a significant amount of time keeping those legs clean. Like a cat, it will groom itself, meticulously making sure that everything is in proper order.  So next time you see one of these centipedes crawling out of your drain, try not to scream or panic, and remember that this is one bug that you don’t want to squish.