Here be Dragons

Worldbuilding blog for my creatures

[moryonenn]

paint brush in my cup of tea. I'm devastated

[artifacts-and-arthropods]

The Sea Mouse: this marine worm's body is fringed by photonic crystals that emit colorful displays of light

The scientific name of this species is Aphrodita aculeata, which is a reference to the Greek goddess of love and beauty, Aphrodite. It's also known as a sea mouse, thanks to its fluffy, almost mammalian appearance, but it's actually a type of marine worm.

Above: the photonic crystals have a color-shifting effect that makes them look almost like fiber-optic threads

The sea mouse is equipped with tufts of hollow, glassy bristles that produce a vibrant iridescence; these structures are known as photonic crystals, and Aphrodita aculeata is one of the few living organisms that is known to produce them.

Above: Aphrodita aculeata

This article explains how the colorful effect is produced:

Each sea mouse is covered in a dense felt of bristles that keep silty sediments away from the gills. But these "hairs" aren't hairs at all. The structures, known as chaetae, are actually modified scales, made largely of chitin, the same material that gives insects like jewel beetles their iridescence. 

Each spine is essentially a hollow tube, and the wall of that tube contains 88 perfectly hexagonal chitin cylinders. Acting together, these cylinders form what is known as a "complete spectrum photonic crystal", the first-ever documented in a living organism. Photonic crystals are nanostructures that affect the motion of light travelling through them, and the sea mouse's crystalline spines are the most efficient in nature. 

Above: close-ups of the iridescent bristles

According to the same article:

As light hits the system of chitin tubes at different angles, it is spilt, scrambled and bounced back, producing the ever-changing rainbow you see. Light that comes in perpendicular to the spine reflects a deep red. Light coming in from off-axis angles, however, results in brilliant blues and greens.

Amazingly, the spines' ability to bend light surpasses even the most brilliant non-living photonic crystal we know of, the fire opal.

Above: the underbelly of a sea mouse, with a close-up of the "feet" (parapodia) along the sides of each body segment

The purpose of this colorful display is still unclear. Many researchers believe that it is used to deter predators, while others argue that it might help to obscure the sea mouse's silhouette as it moves along the bottom of the sea, making it harder for predators to pinpoint the exact location of its body.

Above: the photonic crystals shimmering as the sea mouse moves around

The genus Aphrodita contains several other species that are commonly known as sea mice, but Aphrodita aculeata is the only one that can produce this iridescence.

Above: the colorful effect is more vibrant when viewed underwater, but it's still visible even on land

Aphrodita aculeata has an average length of about 7-15cm, and it can be found in certain parts of the North Atlantic, the North Sea, the Baltic, the Arctic, and the Mediterranean.

Sources & More Info:

Marine Life Information Network: Aphrodita aculeata

BBC Wildlife: The Sea Mouse is a Psychedelic Fuzz of Fur and Spine, and a Master of Photonic Communications

Acta Zoologica: Hairy and Iridescent Chaetae of the Sea Mouse

The Wildlife Trusts: Sea Mouse

Earth Touch News Network: This Rainbow Wonder is One of the World's Weirdest Worms

The Quekett Microscopial Club: Sea Mouse Hairs

BBC: Sea Mouse Promises Bright Future

[horsefigureoftheday]

Sucks how many people were taught that "horses put their ears back when they're mad" but then never taught the difference between "angry backwards ears," "mildly annoyed backwards ears," "pain backwards ears," "concentrated backwards ears," "sleepy backwards ears" and "just happens to be listening to something behind it."

"Horses put their ears back when they're mad" idk man i think it depends

[horsefigureoftheday]

These are all completely different expressions in completely different scenarios, and only two of them are decidedly negative.

[horsefigureoftheday]

Actually, I wanna talk about the third horse, the one putting its ears back in pain. Over the last 15 years veterinarians and animal scientists have worked out pain scales for most domestic animals by taking photos of the during routine procedures.

We know vaccines painful, and by comparing horses at rest with horses getting vaccinated, we've been able to determine how they express pain visually. By looking at horses with disorders like colic, broken bones, wounds, and so on, we can determine their facial expressions during more severe pain.

At zookeeper school we were drilled through the pain faces of the most common lab animals and livestock. Nowadays I believe this has become a routine lesson in all animal related fields, but the general public still doesn't know that this is a thing that exists.

Here are all the pain face/grimace scales I've been able to find. Please study them if you interact with any of these animals on a regular basis:

[literallymechanical]

[literallymechanical]

They breathe by flexing their pelvis, which is attached to the liver, which is pulled backwards to inflate the lungs. This is called the "hepatic piston."

[moryonenn]

Nichetember 31

Piale are small omnivores, often found foraging on the forest floor, but also capable of climbing. They often live in social groups of five to ten members.

[moryonenn]

Nichetember 30

Gehnrebi are specialised to hunt kan, with a long, compact body which allows them to enter the kan kjas trees where the kan live. A gehrebi will guard a territory of two or three kan kjas from other gehnrebi.

[moryonenn]

Nichetember 29

Utjua are are a keystone species as the primary predator of ymuise, which can easily overburden the forest if their populations get high. They hunt from trees to avoid the ymuise's claws.

[moryonenn]

Nichetember 28

Kioli are flying insectivores. They carry their young until they mature, so are limited to raising one child at a time.

[moryonenn]

Nichetember 27

Ymuise are small omnivores that dig up roots and invertebrates with their clawed front limbs, and will also scavenge carcasses and any nests they can reach. They can produce multiple litters in a year.

[moryonenn]

Nichetember 26

Introduced by human terraformers a long time ago, tiny nematodes are as ubiquitous here as they were on Earth. They are largely unknown due to their size.

[moryonenn]

Nichetember 25

Tjénfi are mimic the shape and pheromones of tjenfi. They live in tjenfi nests for protection and act as worker tjenfi most of the time.

[moryonenn]

Nichetember 24

Amtual are ambush predators, hunting by digging a shallow ditch to hide themselves while awaiting prey, then pouncing with their powerful hind legs.

[moryonenn]

Nichetember 23

Udi are cursorial predators and mostly solitary, although they do sometimes associate with siblings. They retain large wings despite being flightless, to use as a gas exchange and heat transfer surface to recover after running.

[moryonenn]

Nichetember 22

Aneruni are aquatic seasonal visitors to the rivers of south-east Ofima, migrating to spawn once a year. They don't eat for the whole journey, because they rely on their prey schooling in open waters to hunt. Aneruni are be opportunistically preyed on by kiu.

[moryonenn]

Trick or treat!

You get starch paper rolls from Ahmket, filled with chopped nuts and spices, and sealed with a glaze.

[moryonenn]

Nichetember 21

Etji are fossorial organisms, with digging limbs derived from wings. Hardened keratin spines stiffen them for this purpose. Etji eat small invertebrates that fall into tunnels they dig.

[moryonenn]

Nichetember 20

Kan live symbiotically inside the domatium of kan kjas trees. They live in a eusocial group with one female and several males who reproduce, while the rest are workers. A small number of kan will leave their colony permanently to become a reproductive member of another.