There are currently around two million know species on Earth and scientists currently believe there are around 8 million still waiting to be discovered. Every year, more than 10,000 species are discovered, but we managed to whittle down the latest batch from 2015 to just our favourite five.
The following list contains animals which made us smile from their sheer cuteness, and those which made us squirm because they could be the stuff of nightmares.
Saddleback Toad - Tiny frog smaller than 1cm
We're kind of cheating on this one, because there were seven different species of these frogs discovered at the same time. These incredibly colourful frogs of the Brachycephalus genus are so tiny (less than 1cm long) that it took scientists ages to spot them in the Brazilian rainforest. Their only lead was the sound of them singing.
Marcio Pie, Professor at the Federal University of Parana, told BBC News: "You can hear them singing and there's probably hundreds of them, but you simply can't catch them! Because once you get closer, just from the vibration in the ground, they keep silent, for 20 minutes or half an hour. And then you have to go through the leaf litter very carefully with your hands."
Discovering the species took five years of hard work, and the results were published in PeerJ. Since July, when these frogs were first spotted, the team have found even more tiny frogs and are yet to publish the findings of another four species. The researchers think there are still plenty of Saddleback toad's out there, and the search continues.
Blue Bastard - Fish attacks its enemies by smothering them in kisses
This ocean-blue coloured fish proves that love always beats hate. The 'Blue Bastard' – named by local Australian fishermen because of its particular difficulty to catch – attacks rival males in a very unique manner. To defend their territory, two of these fish will rush toward each other and then lock jaws in violent struggles. To any human outsider, it appears like a particularly passionate kiss.
Jeff Johnson, the fish scientist that was first sent the pictures of the new species, said: "It's quite a unique fish in both biology and behaviour, so in a way it's surprising it took this long for it to be officially recognised as a new species."
Before the discovery was officially registered, the Blue Bastard was only known to the Queensland fly-fishermen as a local rumour – similar to the myths surrounding the Loch Ness monster.
Circle Builder - Pufferfish makes underwater crop circles
For twenty years, experts have been wondering what has been making intricate Spirograph patterns at the bottom of the Pacific Ocean, just off the coast of Japan. Now, it has finally been revealed that female Torquigener albomaculosus pufferfish makes these patterns to attract a male.
Scientists say that the designs also act as a defence mechanism for eggs, which can be quite nicely protected at the centre of the pattern. This is the 21st species of this type of pufferfish, and coincidentally the genus of the species loosely translates to 'circle builder'.
Flic-Flac - Spider that cart-wheels away from trouble
Most animals would scurry away from enemies as fast as their legs can carry them, but this newly discovered species of Moroccan spider chooses to be a bit more dramatic, and cartwheels away.
The spider, nick-named 'Flic-Flac', can jump two metres per second making it twice as quick than just walking. This speed comes at a cost though, as it uses a lot of energy – especially in the desert environment where it is found – and can ultimately lead to its death.
"Like a gymnast, it propels itself off the ground, followed by a series of rapid flic-flac movements of its legs," said Peter Jäger, discoverer of the species. "This gives the spider great flexibility – uphill, downhill or on level ground, Cebrennus rechenbergi can move along with ease." Jäger adds that Flic-Flac only tends to display this behaviour when provoked. This could be from an angry scorpion, or even a wandering human.
This thing - Pink blob
We don't actually know what this is – or even what it could to be. But it's weirdly absorbing just watching it float underwater.
The pink blob-like jellyfish-thing was recorded in June this year when the exploration vessel, (E/V) Nautilus, recorded a number of bizarre underwater species. The recording was taken near deep sea thermal vents, off the coast of the Galapagos Islands, near Ecuador.
After the video was examined by the researchers, it was then posted on social media, for Twitter and Facebook to try and make sense of – to not much avail. Here's the footage; see what you make of it...