As a naturalist, we love nature and believe that the world along with its unique living creatures is astounding. We've selected 50 examples of species most of us have never even heard of. Don't miss the bonus at the end of the article since it may be the coolest part!

Slender loris: This is a very slow animal that mainly lives on trees. They look very funny with huge eyes and a surprised look on their face. That expression gave them the name "loris" which means "clown." They don't have a tail and use their hands and legs to move from one tree to another.

Sea pig: These animal are not rare but they got into our selection for their weird appearance. They live in all of the world's oceans, but usually so deep that most of us will never see them. They play an essential role in the world's ecosystem by basically cleaning the ocean. They spend their whole life "walking" on the ocean floor and eating whatever they find, from decaying plants to dead animals.

Purple frog: It's no wonder how this creature got its name. The purple frog is the only survivor from a group of amphibians which evolved 130 million years ago. Spending most of its life underground, the adult purple frog only comes to the surface for a few weeks a year for breeding. It's not a bright purple, it's more of an earthy purple color that's unique to a species known for wide-ranging colors. The color is varied from dark across the back to an almost light brown on the stomach and feet.

Arapaima: This fish is huge and can grow up to 4.5 meters long. They live in very dirty water which doesn't have much oxygen in it. To survive, this fish developed a special swim bladder and can gulp air from the surface. They have massive mouths and can catch not only a relatively large fish, but even a bird, when cruising on the surface.

Andean condor: This is a REALLY large bird. Its wingspan can reach 3 m (10 ft) but despite such impressive wings, the Andean Condor is not the greatest flyer. It struggles to stay aloft when flying, mainly because of its weight, but it feels very comfortable in windy areas where it can glide on air currents which can help it rise to very impressive heights.

Aye-aye: This is a very weird looking animal. They only live on the island of Madagascar and there was a time when they were thought to be extinct. Although some animals were found in the mid-20th century, they are still considered to be endangered. An interesting fact about them is that their teeth never stop growing. To keep this under control they constantly chew nuts and wood.

Northern bald ibis: This bird prefers to live close to running water and normally stays in a group. Its distinguishing characteristic is a black glossy body and absolutely unfeathered red face. They used to be wide spread but water pollution and habitat issues have made them critically endangered. It's believed that there are only about 500 birds left in Morocco and just a few in Syria.

Spoon-billed sandpiper: This is one of the rarest birds in the world. It has a very unique looking bill, which gave this bird its name and looks like a spatula. This bird breed lives in the north of Russia along the Bering Sea coast, migrating down for winter. There was a time when they nearly became extinct and a lot of successful efforts are currently being made to save them.

Gooty sapphire ornamental tarantula: Most of people don't like spiders, but you have to admit that this is a very pretty one. Although there has never been a reported human death from its bite, it's a good idea to stay away from it. These spiders can be quite aggressive and their venom can cause severe pain.

Tonkin snub-nosed monkey: This is a small, cute monkey which can only be found in some parts of China. It has nostrils very close together like a human and human-like hands with long fingernails. They have a thick pad of skin around their tail which works as cushion when they are sitting. Since they live in a very cold climate, they have developed a beautiful coat which covers their entire body except for their eyes, nose, and mouth.

Roloway monkey: Predominantly black, with a few white patches at the throat and the arms, roloway monkeys are distinguished by their pointed white beards. They are critically endangered and we can only hope that these fascinating animals stay with us. They are very particular about where they want to live and have only been found in a few areas of Ghana and the Ivory Coast.

Angonoka tortoise: This is another species endemic to Madagascar that is critically endangered. These tortoises have a very cool shell coloration and structure and very noticeable growth rings on each segment. Sadly to say, the number of these amazing tortoises is still going down.

Jamaican iguana: The Jamaican iguana is endemic to Jamaica and was believed to be extinct until a local hunter bumped into a few of them in 1990. At the moment only 50 survivors have been reported which makes the Jamaican iguana the rarest lizard on the planet. Historically, these iguanas used to inhabit a much larger range on the southern coasts of Jamaica, but today they can only be found in a location known as the Hellshire Hills. This dry forest full of rocky, limestone outcrops is considered one of the world's most threatened ecosystems, and iguanas can really only be found in its most remote corners.

Marabou stork: A giant bird with a giant appetite, the Marabou will eat just about anything. They actually play an essential role in the balance of their ecosystem by cleaning up the carcasses of dead animals. They have an ugly red sack hanging from the outside of their throat that they can inflate to show their dominance.

Basking shark: The basking shark is a plankton eating shark, but it looks terrifying. These sharks are the second largest on the planet and known for having a massive liver, which comprises approximately 25% of their body weight. They were considered endangered not long ago due to extensive hunting, but their numbers have been rising lately.

Scaleless blackfish: This tiny, very bizarre looking fish was recently discovered living inside an underwater volcano near Australia. It certainly fits into our selection because of how weird it is! It was found only a few years ago so we should take it as a message that ocean still holds many surprises for us.

Chimaera: This fish is related to sharks. Their unique characteristic is that they have a cartilage skeleton and despite their large size they are very graceful swimmers. A chimaera is a strange fish that has a network of lines over its surface. The lines often look like seams. They give the impression that the animal's body has been created by stitching together parts of other creatures. The appearance is reminiscent of the chimera, a creature in Ancient Greek mythology whose body consisted of parts of different animals joined together.

California condor: When Europeans arrived in North America, condors could be found everywhere. By 1985 the entire known wild population had been reduced to just 9 birds. After a lot of effort and a large program to increase the population, the number was significantly enlarged but they are still considered to be one of the world's rarest bird species. Condors are so large that they can be mistaken for a small, distant airplane. When in flight, the movements of the condor are remarkably graceful. They really excel at gliding, sometimes going for miles without a single flap of their wings.

Puppy-face saddleback caterpillar: This interesting-looking caterpillar really looks like a puppy wearing a coat and is much prettier than its "grown up" version – a moth native to North America. Most of its body is covered with hair which produces an irritating venom and if you touch it you are very likely end up with a painful swollen rash.

Tarsius: These little primates have a very interesting appearance and look more similar to lemurs, than monkeys. They spend their entire life in trees, sleeping, eating, reproducing, and just jumping from one tree to another. Unfortunately, they are extremely rare now, mainly because of habitat loss.

Blue-footed booby: This gorgeous bird looks slightly surreal with its bright blue feet. They got their name from the Spanish word "bobo" which means "foolish." The reason for this is that these birds walk very funny on land. North Seymour is one of the Galapagos' best seabird breeding grounds, with blue-footed boobies occurring at high frequency. Large breeding populations can also be found on many other islands south of the equator – including Espanola, Fernandina, Floreana, Isabela, Pinzon, and Santa Cruz.

Chinese water deer: These beautiful animals have a very unique feature, male deer have long canine teeth, which can grow up to 8cm long. They are very territorial and males use their fangs in fights. They are also fantastic swimmers, capable of swimming for several kilometers between islands. It is the only species of deer in which males lack antlers; instead, they are armed with long, curved, and sharp upper canine teeth that protrude from the mouth. These tusks may exceed 5 cm (2 inches) in length. The water deer is also the only deer with inguinal glands.

Patagonian mara: This animal, which looks like a crazy mixture of a few animals – the ears of a rabbit, the front legs of a deer, the rear legs of a kangaroo, and a cute short tail. They have only been found in Argentina. The Patagonian mara is an excellent runner and jumper. It can run up to 30 mph and leap up to 6 ft in the air.

Mantis shrimp: Technically they are not shrimp, they are actually stomatopods which are relatives of shrimp, crabs, and lobsters. They have a very serious and extraordinary weapon – powerful hummer-like and very sharp claws which they can accelerate at a speed of 53 mph. When scientists study them, they have to use plastic tanks because this little thing can easily break glass.

Okapi: Okapi have stripes like a zebra but their shape resembles their close relative, the giraffe. The males have a feature found only in these 2 animals: small horns on their forehead that are covered in skin which never shed. Okapi also have super-long tongues which they can wash their eyelids with.

Lowland streaked tenrec: This is one of the most unusual looking animals that can only be found on the island of Madagascar. It looks like a cross between a shrew and a hedgehog. They can make very weird sounds called stridulations by moving the spines on their back. Some insects like crickets make this sort of sound, but these animals are the only mammals who can do this. They also click their tongue and use this noise for communication.

Pacu fish: Pacu fish became well-known for the shape of their teeth, which are not sharp and pointy like most fish have, but flat and more human-like. This tooth shape allows pacu fish to crunch food like nuts. Pacu are related to piranhas, but happily eat plants as well as sea protein.

Bonus: Northern white rhino. This year the world said goodbye to the last male northern white rhino, and right now we only have two of these beautiful animals left on the entire planet. They are under watch 24/7 and armed by guards. But unfortunately, both of the rhinos left are female which means that unless scientists come up with some bright idea, our generation will soon be facing a very sad reality: the complete extinction of these animals. This should serve as a lesson to everyone who reads this article. Nature is fragile and some damage is irreversible. Unless we start taking care of our planet and its inhabitants, future generations will live in a very different world, and not in a good way. This time for change starts now. The world around us is full of amazing things and we couldn't possibly mention everything. If you want to share something interesting, that would fit into this article, tell us about it in the comments.