Finally an updated reference sheet of the Siderian species (a horse-sized northern big CAT).
Full size: https://www.deviantart.com/felisgla.....2021-898592461

I’ve decided to keep the old ones as well so you could compare if you want to - see my DA account https://www.deviantart.com/felisgla.....erian-biology.
I’ve changed to scientific name from Metafelis lamnis to Metafelis borealis. The old name was referring to the little metal spikes on the muzzle and ears. I tried to analyse what they are for and I forgot them so often that I wondered; do siderians really have them and do they really need them? Not really. So that means the species name should change too. Since they are predominantly inhabiting northern regions the name Metafelis borealis would fit well.

Note that this reference sheet shows a shorthaired siderian – this is just to show the anatomy. Siderians tend to have longer coats and I will show that in later reference sheets. I’m also planning on making a new siderian anatomy sheet and an overview of the types of individual variation.

Some species information from the older refsheets:
Social behavior: they hunt mainly solitary and sometimes in pairs. Occasionally they hunt together with several friends or family members. Siderians are quite social for felines and their society is comparable with that of feral cats: a fission fusion society. Rather tolerant and social where resources are plenty but both genders can be territorial where resources are scarce. Relatives tend to share a territory and they often form large family territories with smaller subsections for each couple or individual. Both genders may disperse from the family to find a mate but males tend to leave more often than females and they may go further.

Mating system: variable per region but predominantly monogamous with biparental care. Polygamy is also quite common in certain cultures. In that case, females (often relatives) tend stick together to raise their cubs. Generally, siderians are more polygamous when younger and may settle with a permanent partner later in life. Herb based anticonception and restriction of mating frequency prevents unwanted births in young, sexually explorative siderians.

Diet: exclusively meat. Prey species varies, but mostly large ungulates. Siderians are generally highly opportunistic and are not very picky with their prey.

Reproduction and lifespan: siderians are reproductively active year-round but mating is most intense in autumn and most cubs are born in spring. Female estrus cycles are slightly seasonal with more intense and shorter cycles in autumn. Gestation is about 6 months. One kitten per litter. Siderians tend to get 1-4 cubs in their life. Cub survival chances are quite high. Lifespan between 100-120 years, with extended childhood, like in humans and some other animals.
Circadian activity: they are mainly crepuscular (most active at dusk and dawn) and sleep during the middle of the day and middle of the night (4-5 hours during each sleepign bout, so 8-10h per 24h). There are different chronotypes among siderians with variable preferences for more dawn- dusk- day- or night activity.
Habitat: temperate and boreal forests and mountainous areas. They prefer to have good cover for hunting and prefer forests over tundras or mountains but some siderians thrive well in open landscapes.

Distribution: the northern hemisphere, mostly at higher mid-to higher latitudes.

Phylogeny:
Kingdom: animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Suborder: Feliformia
Family: Felidae
Subfamily: Felinae
Genus: Metafelis
Species: M.borealis
IMPORTANT: Siderians are a semi-open species. You don’t need to ask permission to draw one or have your own character to roleplay with. That’s fine for me. However do NOT claim them as your own ‘design’ and it is appropriate if you refer to me if you draw a siderian. I do NOT allow making adoptables.

Also - I suck at typing. There may be some typos and plz don't hesitate to tell me ^^
Also2 - if this sheet is going to get tagged as mature content just for showing some anatomical details, I will say: then you should tag your cat as mature content every time they raise their tail!