(Theories and other stuff found ingame, like the Ancient Nichelings migrating to other areas, are my headcanons and may not be true)

Welcome to my journal. This is the first chapter of the journal: The animals!
I'll start with an iconic predator:

Diet: Carnivore
Prey: Rabbils, Nichelings
Predators: None
Competitors: None
Scent: Red (Dangerous!!)

These carnivores are easily recognized by their claws, face, ears, and body shape. They are dark brown with lighter-colored fur around their darker brown eyes. They are usually found alone, however occasionally you'll encounter a mother bearyena with their baby. Baby bearyenas have a curiosity around nichelings and sometimes let themselves live around them. Bearyenas and nichelings kill each other for food. They are nocturnal and move at night, searching for sleeping prey like rabbils or nichelings.
There are other variants of Bearyena, such as:

Diet: Carnivore
Prey: Rabbils, Nichelings
Predators: None
Competitors: None
Scent: Red (Dangerous!!)

These rare bearyena variants are extremely dangerous and should be watched out for in the wild. They are twice the size of a nicheling and are noticeably bigger than the regular bearyena. They have large red eyes and dark fur that goes down from their neck to the rest of their bodies. Thankfully, they are native to Deadly Hills, and aren't found elsewhere.

Diet: Carnivore
Prey: Rabbils
Predators: None
Competitors: None
Scent: Green (Safe!!)
The friendly bearyenas start out as babies and live with their mother until they're older. They depend on their mother to survive and get fed, and seem confused when left alone. Tribes of nichelings seem to be smart enough to give the bearyena food to tame it. When the friendly bearyena gets older, it is able to hunt for itself. During the day, when it is asleep, nearby nichelings and other creatures can steal its catches for themselves. When the bearyena is old enough to find a mate, nichelings can breed with the bearyena to have offspring with rare genes not seen anywhere else in the wild.

Notes:
Bearyenas do not attack toxic-bodied nichelings or nichelings who have growled at them. They may understand the dangers of attacking poisonous or intimidating creatures.
Bearyenas don't seem to care about stagmoles, however I am not entirely sure.
Bearyenas were called "Carnivores" in the past.

Now that I've talked about what I've learned about Bearyenas, it's time to talk about the next predator:

Diet: Carnivore
Prey: Baby Nichelings
Predators: None
Competitors: None
Scent: None

These predatory birds might not seem important at first, but they are dangerous around young nichelings. They can be recognized by their large wingspan, blue feathers, and pale yellow eyes. If they spot a baby nicheling or meat pile unattended, they'll try to fly as quickly to it as possible before an older nicheling moves toward it. If they are successful with flying to a nicheling, they'll grab it off the ground, and the nicheling will never be seen again. They are diurnal, which means they fly during the day. They sleep while flying at night. They don't seem to have any predators or competitors, but very rarely I can see them being plucked out of the sky by winged nichelings.

Notes:
They are often called bluebirds.
Ancient birds of prey could fly faster than modern birds.
Pointed out by SunBloom, Birds of Prey also eat rabbils and unattended meat.

Now moving on to one of the stronger creatures:

There are three types of apes: The Seeing Ape, the Smelling Ape, and the Hearing Ape. They are all unique but equally dangerous. I'll go over the apes one at a time, starting with:

Diet: Omnivore (Not sure.)
Food Source/Prey: Nichelings
Predators: None
Competitors: None
Scent: Red (Dangerous!!)

This Ape can be recognized from its dark fur and lighter skin, its teal accents, but most importantly, its long nose. It specializes in smelling, so my suggestion is find a way to either give yourself a stinky scent, or remove your scent at all. There is mud that can be found frequently in the jungle. Rolling around in the mud will guarantee survival, assuming you aren't too close to the ape. There are weirdly-shaped trees in the jungle with odd-smelling, but delicious, fruits dangling from their stems. While they are nutritious and delicious, the stinky juices that they secrete attract the Smelling Ape. My theory is that the Smelling Ape is either omnivorous, and their big nose is an adaptation for finding food such as Smelly Fruit or Nichelings, or that they are mostly carnivorous and use the Smelly Fruit Tree to find prey.

Diet: Omnivore (Not quite sure.)
Food Source/Prey: Nichelings
Predators: None
Competitors: None
Scent: Red (Dangerous!!)

The Seeing Ape has shaggy yellow fur with grayish brown skin and greenish stripes. It has two large blue eyes that it uses to see. As long as you stay out of its very large line of sight, or find out a way to scare it with your appearance, you'll be fine.

Diet: Omnivore (Not confirmed.)
Food Source/Prey: Nichelings
Predators: None
Competitors: None
Scent: Red (Dangerous!!)

The Hearing Ape has darkish green fur with lighter spots and dark gray skin. The insides of its huge ears, which it uses to hear, are purple. This ape relies entirely on its sense of hearing. Two good tips I recommend to try to keep the Hearing Ape at bay is to either make yourself incredibly silent, or scare it away by making a loud, threatening noise. Be careful of any twigs or leaves you find in the jungle, or you might alert the ape.

Notes:
All Apes have fangs, suggesting they may have used these fangs to either make their prey bleed to death, or to poison their prey long ago. I'm sticking to the latter theory because they may have evolved their venom out but retained their poison resistance.
The Apes are very durable.
They are often referred to as the Great Apes.

Diet: Carnivore
Prey: Nichelings, Rabbils, Walrus Deer
Predators: None
Competitors: Balance Bear
Scent: Red (Dangerous!!)

Arctic Ramfoxes have pale white fur to blend in with the mountain snow. They have ram horns and sharp claws that are both dark blue. They are rarely found on their own and travel in packs. They are scavengers and sometimes grab any meat they can find, but they aren't afraid to fight if they need to.

Notes:
Arctic Ramfoxes have excellent eyesight, being able to see 5 tiles from them.
They sound like their namesake when attacked: Foxes.

There are three types of bears, with all of them being found nearly anywhere in the world, from the grasslands of the Grass Mingle, to the cold mountains of the Frost Lands, to even jungles like the Overgrown Jungle. Lets start with the carnivorous bear native to the mountains:

Diet: Carnivore
Prey: Walrus Deer, Nichelings
Predators: None
Competitors: Arctic Ramfoxes
Scent: Red (Dangerous!!)

Balance Bears are large, carnivorous bears with white fur. Along their backs is blue fur that gets darker around the center of their backs. Their paws and long, bushy tail are also blue. Darker blue can be found in their inner ears, eyes, and dots along their back. Their underbelly is slightly darker than the surrounding white fur. They are strong and bulky, but also slow. As long as you aren't next to the bear at night, you'll be able to survive.

(No photo available)
Diet: Omnivore
Food Source/Prey: Unknown
Predators: Unknown
Competitors: Unknown
Scent: Yellow (Neutral)

Not much is known about Defender Bears. They are very rarely seen in the wild. They are either critically endangered, or completely extinct. From the old photos and pictures, they had dots for eyes and were moss-brown with patterns of a similar color. They seemed to attack anything that attacked something else, itself included.

Diet: Herbivore
Food Source: Grass
Predators: None
Competitors: None
Scent: Green (Safe!!)

Peaceful Bears can be identified by their sitting stance, round body shape, and welcoming smile. They are moss-brown with round ears and eyebrows that stick out. They have their sclera surrounding their black eyes. They are peaceful, lazy, and slow, and spend their days collecting regrowing grass. However, if provoked, they are not afraid to fight back. If offered nesting material by a nicheling, they will become replete and protect the nicheling tribe for a short amount of time. They can be found in both green grasslands and mossy jungles.

Notes:
Bears, like the Apes, are strong and can live for a long time.

This is a very complicated section, because Nichelings are one of the most diverse animals in the world of Niche.

Diet: Omnivore
Food Source/Prey: Rabbils, Stagmoles, Berry Bushes, Acorns, Coconuts, Fish Swarms, Clownkoi, Razoranhas, Bearyenas, Roots, Walrus Deer
Predators: Bearyenas, Balance Bears, Arctic Ramfoxes, Apes, Birds of Prey
Competitors: Other Nichelings
Scent: There seems to be more than one scent for Nichelings. Some are yellow, others are red. It really depends on their personality or intentions.

Nichelings are hard to understand for me. Their unstable genetics allow them to take on various appearances and abilities. They live either on their own or in tribes. Nearly anything is their food. They seem to be diurnal and sleep at night. They have three gems on their chests that show how energized or sleepy they are. Instead of understanding them individually, I've decided to understand the tribes that they live in.

Preferred food: Meat

These Nichelings live in normally dangerous environments, like Deep Jungles, Frost Lands, and even Deadly Hills. To them, predators are prey. Berry Bushes are nearly useless to them. They usually have a high Attack stat, but often also have Fishing and Defense stats. They mate with Friendly Bearyenas for strong genes. They usually have Claws.

Preferred food: Fish

These tribes are rarely seen because they spend nearly their entire life in the ocean. To breathe, they usually have Water Bodies or Gills. They also have other swimming genes, like webbed feet or tailfins. On land, they are slow and clumsy. They often eat fish swarms, razoranhas, leeches, or, if they're lucky, clownkoi. To fish, sometimes they have long, thin tails or claws to catch fish. Very rarely, they have platypus beaks to dig up worms off the seafloor. Tribes closer to the surface sometimes have beige fur to aid in camouflage.

Preferred food: Meat/Roots

These tribes eat meat and sometimes roots, however they very rarely snack on berry bushes if they are available. They have fluffy bodies that sometimes radiate heat to help them in the cold. They often have white fur to help them camouflage in the snow, but sometimes they can even be albino. They often prey on rabbils, but if they can't find any, arctic ramfoxes are the next best food source.

Preferred food: Plants/Meat

Because these tribes live under the dizzying desert sun, they have special genes that allow them to survive in such a hot climate. They have sparse-furred, lean bodies that also help them run from predators or fires and big ears that dispel body heat. Sometimes they have claws, long legs to run, or nimble fingers. They also sometimes have long snouts with sticky tongues or bat heads with large ears to collect insects. They also sometimes have poisonous scorpion tails or gazelle horns to attack predators with. If they live in an oasis, they also have claws to fish.

Preferred food: Plants

The Nichelings that live in these tribes live in a dangerous ecosystem, full of apes and carnivorous plants. To counter this, they have big ears to escape the Jungle's heat, silent paws to get away from Hearing Apes, stinky tails to scare away Smelling Apes, toxic bodies to intimidate Seeing Apes, and big noses to smell whether a meat eating plant is hostile or safe. They know their way around the terrain and watch out for twigs. Rarely, they have digging paws to dig up roots from the ground, or cracker jaws to collect acorns that can be seen falling from Ape Trees. They go to Smelly Fruit Trees in parties of at least two; one to collect the Stinky Fruit, and another to lick the syrup off them, to avoid Smelling Apes.

Preferred food: Plants/Nuts

These Nichelings are the calmest but also often the weakest. They usually have regular, medium bodies, but they sometimes have lean bodies for speed. They have either long runner legs, soft velvet paws, or nimble fingers. They often have short snouts but can also have long noses or cracker jaws. Very rarely they are seen with horns or claws. They run from any threat and rarely eat meat. They are otherwise very gluttonous and lazy, and spent their days collecting food or cracking nuts. They come in a variety of colors; no two Nichelings look alike.

Preferred food: Nuts/Meat

These Nichelings live nearly their whole lives in trees. They have either one or two wings or bat wings, but sometimes it's both a feathered wing or a bat wing. They collect nuts from the tops of trees or swoop down to attack unsuspecting rabbils. In a swamp, they perch onto mangrove trees to collect the snails that rest on the top of them.

Preferred food: Meat/Roots

Long ago were tribes with ancient prehistoric genes. They lived in the mountains where all was calm for the most part. When blizzards formed, they migrated to other, safer islands. Eventually, with no need for their genes, they evolved their valuable genetics out, resulting in the genes we have today. However, some Nichelings didn't escape the blizzards and froze solid in ice for millions of years. When the Nichelings of modern days found the ice blocks, they cracked them open to reveal the ancient genes of long ago. Now there are tribes with formidable and powerful prehistoric genes. The ancient genes are strong, designed to survive in the mountains. They are very colorful and different all in their own ways.

Preferred food: Anything!

These are arguably the most common tribe in the world of Niche. They eat anything they find, whether it be berries from a bare berry bush, or meat from a Bearyena. They rarely look alike; one could be red with brown spots, blue eyes, savanna horns, a claw and a digging paw, and a medium tail, while another could be melanistic with green eyes, antennae, a bearyena claw and a nimble finger, webbed hind legs, and a fishing tail. Sometimes, they are nomadic. There's no limit when it comes to these tribes, only one rule: survive.

Diet: Omnivore
Food Source/Prey: Berry Bushes, Roots, Meat Piles
Predators: Bearyenas, Balance Bears, Arctic Ramfoxes, Apes, Birds of Prey
Competitors: Other Nichelings
Scent: Yellow (Neutral)

Wandering Nichelings are nomadic Nichelings that wander around looking for food. Like other Nichelings, they collect food to eat. They will be happy to join any tribe as long as there is food. They can be found anywhere, from the grasslands to savannas to mountains to jungles to even underwater.

Diet: Omnivore
Food Source/Prey: None
Predators: Bearyenas, Balance Bears, Arctic Ramfoxes, Apes, Birds of Prey
Competitors: Other Nichelings
Scent: Red (Dangerous!!)

Rogue Males can be found nearly anywhere, with some exceptions like Tiny Green or Archipelago. Their main goal is to expand their family, and their next target is a Nicheling tribe. Rogue Males, like all other Nichelings, come in a variety of appearances, however they all share three common traits: they all have derp snouts on both gene slots, they all have two deformed paws, and they all seek to impregnate the tribe's females. Many Nichelings consider them a nuisance because they want to spread their genetics to the tribe's.

Notes:
Wings have been around for a long time, because some Nichelings trapped in ice blocks have wings.
Nichelings around the same time as the prehistoric Nichelings seemed to be faster.
Nichelings in Ancient times had different, solid-colored eyes and relied heavily on their eyesight.
Nichelings way before the Ancient times had extraordinary genetics that allowed them to even see in the dark. Unfortunately, these genetics have been lost to time.
Nichelings may have been around for longer than most other animals.
Nicheling bodies decompose quickly and leave only the skeleton behind after only a short amount of time.

Diet: Herbivore
Food Source: None
Predators: Arctic Ramfoxes, Nichelings, Balance Bears
Competitors: None
Scent: Green (Prey!)

Walrus Deer are large herbivores that are always on the move. They have pale brown skin with blubber on their torso to keep warm. Their legs turn white the closer they are to their hooves. They have two large antlers that they use to defend themselves. They also have two tusks. If it's cornered by Nichelings, it will not hesitate to attack them until it is free.

Notes:
Walrus Deer live only on mountains.
Because Walrus Deer are one of two prey animals in the mountains, they might be regularly hunted by Arctic Ramfoxes and Balance Bears.

Diet: Unknown
Food Source/Prey: Unknown
Predators: Unknown
Competitors: Nichelings
Scent: Yellow (Neutral)

I don't know much about Dodomingoes. They are considered pests to pregnant Nichelings. They are small with a round, grayish body. They have two small wings close to their chest, and their tail takes up most of their body. They have feathers on the top of their heads and a yellow beak. Their main goal is to try to find a nest to call their own, and the nest acts like their home until they are taken or the dodomingo is killed. They sometimes exit the nest to patrol for predators, which gives females the opportunity to nab their nests. If their home is taken, they search for a new nest. If the nest they're interested in is taken before they can sit on it, they stare for a bit before looking for a new nest. They are typically silent and can't be heard. If one is attacked, they send out a cry of alarm that attracts other dodomingoes. Despite being considered pests, some tribes use dodomingoes to search for new nests. Because they drop little to no meat, they may not be hunted by predators very often.

Notes:
All dodomingoes are considered babies, which leaves me to believe that there is a bigger, adult dodomingo somewhere in the world that uses the nests to lay eggs. Because dodomingoes are killed a lot, the adults might not be seen frequently.
Dodomingoes might also be left on their own since birth and their instinct tells them to search for a nest to rest in.

Diet: Unknown
Food Source/Prey: Plankton
Predators: Nichelings, Crabbits
Competitors: None
Scent: Green (Prey!)

Clams, frequently known as simply Shells, can be found in saltwater close to shore. They are often guarded by Crabbits, but commonly eaten by Nichelings with cracker jaws or nimble fingers.

Notes:
Clams can sometimes be found in deeper waters.

Diet: Unknown
Food Source/Prey: Unknown
Predators: Nichelings
Competitors: Razoranhas, Clownkoi
Scent: None

Fish Swarms can be found anywhere with a body of water, be it rivers, lakes, or oceans. The swarms are made up of small, gray fish. A single fish isn't a lot, but Nicheling tribes with claws or fishing tails can fish up many more fish from the swarms.

Notes:
Ancient Fish Swarms were so big that they would be unable to swim through.

Diet: Carnivore
Prey: Clams
Predators: Nichelings
Competitors: None
Scent: Green (Prey!!)

Crabbits are purple crabs with yellow eyes that can sometimes be seen guarding clams. Their behind is their weak spot, so Nichelings usually come in groups of two, but rarely three or even one, to attack the Crabbit when it's looking at the other Nicheling.

Notes:
Crabbits can dehydrate if left out of water for too long.
Crabbits can pick berries off of berry bushes to eat. This is extremely rare and I've only seen one eat during a time of desperate food.

Diet: Omnivore
Food Source/Prey: Unknown
Predators: Nichelings
Competitors: Fish Swarms, Razoranhas
Scent: None

Clownkoi look like what they're called. They are orange, with black and white stripes and long, thin fins and whiskers. They are much faster than the average fish and more agile, allowing them to escape predators easily. They live only in fresh waters and don't last very long in saltwater.

Notes:
Sometimes, Clownkoi find their way into saltwater via a river. Their carcasses, which Nichelings can pick up to eat, are frequently found in oceans.
Clownkoi eventually die one day. This means that Nichelings not well-adapted to areas like the Oasis can pick up their remains for food. (Their bodies eventually decay, so the Nichelings better be quick!)

Diet: Carnivore
Prey: Nichelings
Predators: Nichelings
Competitors: Razoranhas
Scent: None

Leeches, also known as Goldleeches, are small, long creatures that live in the ocean, but rarely in lakes. They have golden skin with a purple mouth and fins that look similarly to legs. They cling onto Nichelings on the shore and slowly drain their blood, attracting Razoranhas. Another Nicheling has to remove the parasite.

Notes:
Leeches may have been called Goldleeches due to the color of their scales, or their resemblance to goldfish.

Diet: Carnivore
Prey: Nichelings
Predators: Nichelings
Competitors: Fish Swarms, Clownkoi, Leeches
Scent: None

Razoranhas are red, carnivorous fish with three fins on each side of its body. It's mostly harmless but attacks any Nicheling that enters the water that is bleeding. It sometimes follows leeches to search for food.

Notes:
Razoranhas can be found anywhere.

Diet: Carnivore
Prey: Nichelings
Predators: Nichelings
Competitors: None
Scent: None

Insect Swarms form when it rains and multiple insects fly around the swamp puddles to breed. The swarms that form as a result chase animals such as Nichelings for food and to spread the Sleep Sickness that they have. The swarms slowly disband after having their food. Nichelings with sticky tongues or bat heads can slurp up the swarming insects before they disband, gifting them food. The insects themselves have muted yellow bodies with translucent dark brown wings. Their eyes are visible and pale yellow. There are also incredibly thin dark brown stripes on their back

Notes:
Insects are native to the Swamps, but sometimes travel away to nearby areas like the grasslands in Grass Mingle or jungles like the Overgrown Jungle.
The Sleep Sickness makes Nichelings sleeping and unable to move very far.

Diet: Herbivore
Food Source: Leaves
Predators: Nichelings
Competitors: None
Scent: None

Snails! They have slimy orange skin with extremely faint lines looking like veins running through their skin. They have two eye stalks and gray pupils, and a green shell. They rest on mangrove trees in the Swamp and emerge when it rains. They can be eaten by flying Nichelings that perch on the trees.

Notes:
Snails :)

(Nichelings for scale)
Diet: Unknown
Food Source/Prey: Unknown
Predators: None
Competitors: None
Scent: None

The Whale can be found exclusively on the bright blue ports that lead to Whale Island. It is the biggest creature I've encountered, bigger than Killer Bearyenas, Bears, or Apes. It is so big that it lets wildlife grow on it, and many creatures reside on the back of the Whale. Once Nichelings reach the head of the Whale, they can command it to go to a specific island, including but not limited to, Tiny Green, Archipelago, Swampy Hill, or Overgrown Jungle.
On the back of the Whale grows various flora, such as berry bushes, cacti, toxic berry bushes, and a variant of tree exclusive to the Whale Island. Near the tail area of the Whale is a barren savannah with little wildlife. Often, the Whale will release water from its blowhole, watering all nearby berry bushes.

Notes:
More about the Whale can be found in other chapters.

Diet: Herbivore
Food Source: Berries
Predators: Nichelings, Bearyenas
Competitors: None
Scent: Green (Prey!!)

Rabbils are small rabbit-like creatures with big ears and a long, thin tail. They have white fur and black eyes. They are frequently hunted by Nichelings and Bearyenas, but are found nearly everywhere. They're most commonly found in grasslands and mountains.

Notes:
Rabbils make their homes in holes on the sides of small hills.
There may be millions of Rabbils inside the burrows, because some Rabbils exit the den for food.
Rabbil tunnels might act like oversized ant tunnels.

Diet: Herbivore
Food Source: Roots (Not confirmed)
Predators: Nichelings
Competitors: None
Scent: Green (Prey!)

Stagmoles have brown fur with lighter speckles, blue eyes, and two antlers on its head. They have two paws with claws that it uses to dig its burrows. Sometimes, stagmoles exit their burrow to patrol or look around, giving Nichelings an opportunity to attack, but if the stagmoles see a Nicheling approaching, they'll quickly hide back inside, not willing to exit its burrow again until it's sure it's safe. If a Nicheling catches a stagmole without it knowing, it will have successfully caught its kill, and another stagmole will eventually exit the burrow in the original one's place.

Notes:
Stagmoles may have evolved antlers to defend themselves from predators, similar to walrus deer. However, they eventually only used their antlers to intimidate predators.

And finally, onto the very last section of the Chapter: The termites.

Diet: Herbivore
Food Source: Grass
Predators: Nichelings
Competitors: None
Scent: Depends if it's aggressive or harmless. If aggressive, it's red, signalling danger. If it's harmless, it's green.

Termites are yellowish bugs that look like... termites. They build large structures out of grass and other organic materials. Sometimes they're aggressive, sometimes they're not. If they're aggressive, Nicheling that crack open their termite mounds will be swarmed by the angry bugs, and another Nicheling will have to lick the termites off. Their exoskeleton will also turn red with anger.

Notes:
Nichelings with insect collecting genetics like sticky tongues, bat heads, and bird beaks can scoop up the termites with ease, while other Nichelings struggle a bit.
Termites are rarely peaceful in savannas.

If you've made it this far into the journal, congratulations! You've learned everything I've learned about the animals in the world of Niche!
However, this is far from the end. There are more chapters with even more sections. There will be chapters on the plants, the islands, and even miscellaneous items like nests and rocks.
This journal will change over time, and people will join me on my journey to learn everything about the world of Niche.
(If I'm missing anything about a creature of anything else, inform me in the comments!)
For now, unless you would like to read the next chapter, until next time.
(Chapter 2 isn't out yet :( )