#zooschool

so Prototheria is basically a subclass of mammals and only has one living classification called Monotremata (basically means first-beasts) and they're called this because these are some of the oldest species living today they are the closest we have to the earliest mammals on the planet and we have five whole species alive today!! ISNT THAT SO COOL???

these things are what the FIRST mammalian life on earth could have looked like! this I'd what WE may have looked like millions of years ago evolution is fucking CRAZY

so what is a monotreme? you already know one by name! Perry the who?

PLATYPUS!!!!

platypus are the only species in their genus called ornithornynchidae which basically means "beaked animals" (I know I know I said no more scientific names but monotremes are an exception since they're so fucking COOL)

so obviously as we all know these are egg laying mammals of action I could get into all the science stuff that makes a mammal a mammal but to keep it simple they have fur and they lactate

so elephant the room what is going on with the whole egg thing? so monotremes have a similar structure that birds and reptiles do they have something called a cloaca that is an all in one hole for getting things out of the body. they use it for all the things we have multiple holes for so what's going on with their reproductive structure??? I'm glad you asked it's weird as FUCK so females only have one working ovary- the right one we don't know why it's just the only one that works

(it could be that the only surviving "platypus" that kept the evolution of these things going just happened to have a broken ovary but we have no idea)

male platypus have 5 X chromosomes and 5 Y chromosomes females have 10 X chromosomes to put that into perspective of how fucking weird that is we only have 2 and things still get jumbled up sometimes.

male platypus are venomous 😀 isn't that a terrifying thought? a venomous mammal- but they are! ...in a way- male platypus have extra fur on their back feet that is sort of like a spine but it excretes poison that is strong enough to kill a medium sized dog- for context these things are maybe a foot long or so they are NOT perry sized

females also don't have nipples

but WAIT roo!!!! how do they lactate if they don't have nipples? guess what guys it's ALSO weird as fuck

they have specialized glands in their skin that secrete milk if it's easier to invision imagine a lot of really tiny nipples all over the place. The babies just lick it off their mother's hair. they actually lactate for a good 20 weeks, which is pretty long considering they are only birthed after 13 days. most of the fetal development is done while in the egg but when they come out they look like pink little fetuses they can't open their eyes or walk or smell anything

OK ok we know enough about sex and birth and shit but did you know they can close their ears? they close their ears with tiny flaps like a seal does when in the water and will also close their eyes underwater. their 3rd eyelid which is the one that closes is white and makes it look like they can see in the water but they can't! they use electroreception just like moles do!

they don't have any teeth other than a few flat ones in the back of their bill and an egg tooth when they are born

bonus fact: a baby platypus is called a puggle :)

OK ok NEXT

Tachyglossidae aka echidnas which means "fast tongued" there's a few types of them but both platypus and echidnas are native to Australia with a few echidnas in New Guinea

so these little guys look like porcupines pr hedgehogs to the untrained eye they have specialized hair that act similar to spines.

they have long snouts and no teeth instead they have bumps on their tongue and a hard pallet that they use to smash their food up against just like platypus do

they do exactly what their name says they have fast tongues coated in sticky mucus to slurp up bugs. they have super strong front legs for digging and females have a pseudo pouch- sort of like a domed abdomen to lay on the eggs with

males have extra spurs on their back feet like platypus do for fighting each other when mating

Skunks

cute little guys <3 I wanted a pet skunk and a pet raccoon as a kid (honestly I wanted a pet everything...) and the good news is you can technically have one! some states (17/50) will allow you to own a pet raccoon or a pet skunk but unless you are very knowledgeable in wildlife care or "exotic" pets I do not reccomend them they are not domesticated like dogs and cats are but can be tame (there's a difference)

anyways some skunk facts;

so their stinky spray is a pretty obvious skunk trait and like the messager mentioned many animals use scent as a way to communicate. pretty much all mammals have a scent gland located somewhere on their body- for many its the top of the head so they can rub pheromones off on trees or other critters to let animals know "hey this is mine" or "hey there handsome.... there's hot singles in your area"

they also mentioned possum and raccoons using scent- opossums are known for playing dead and will secrete stinky stuff to make their act more believable and raccoons? it's their urine and feces that make them stinky

some animals however use scent as a deterrent like skunks do

they are not the only animal that does this all mustelids do (that's the skink, ferret, stoat, etc. fam) and these critters are particularly stinky but don't have the spray adaptation that only skunks really have (as far as I've learned anyway)

both pet skunks and ferrets will often be surgically "de-scented" but usually still have a smell after (I mean... don't we all?)

skunks used to roll with this genus but recently made their own gang called Mephitis (literally means "stink") which has 12 species and includes skunks and "stink badgers" I've also seen some reports of 13 species but I'm not really sure off the top of my head which is true only 4 of them are "true skunks" though

skunks take their scent very seriously guys. some of them will directly aim for the eyes and others will do a little warning dance before spraying they can also adjust their sprays potency and angle and can also choose to spray from both or only one scent gland at a time

(spotted skunk- the dancers)

some can accurately spray 10 feet away but can reach up to 20 or more if they really wanted to soak you but then they have to reload for about 10 days before they can spray anything again

that odor can be smelled from 1.5 miles away! but don't worry 1/1000 humans can't smell it at all and their main predator owls also can't pick up the scent unfortunately for these birds they do still have eyes and a well aimed spray will still take them down

(also the chemical compound in their spray is flammable I have no idea who found that out and why but fun fact!)

if you ever get sprayed don't bother with tomato juice use hydrogen peroxide and baking soda to neutralize the compounds

anyways enough about stink

Skunks are omnivores and some will eat bees aiming for the actual bees over the honey like bears do (yes winny the pooh lied to you he wants that larva not necessarily the honey)

some skunks can be really social living in groups of around 10 and sometimes invite their neighbors to stay with them (there's a few cases of possums staying the night in their den) most of them ate relatively solitary but they aren't very territorial and will overlap sometimes

they are immune to snake venom! another trait that is somewhat similar to their cousins the badgers as they often eat snakes they can handle a lot of poison

alright that's what I know about skunks they're cute little guys but once again

So metatheria are the marsupials of the animal kingdom you've heard of a lot of them and I'm sure you know their calling card- pouches. but we are getting INTO it tonight guys heheheh

ok so some Latin facts- we know that protheria (monotremes) means 'first beast' but metatheria means "in-between beasts"

the first/oldest protheria we know about is the sinodelphys they are found mostly in Australia and South America due to a lack of placental mammals during the whole continental drift business.

ok so what makes a marsupial a marsupial? well let's get into a few relatively universal traits amongst them (remember folks nature doesn't read biology books so some of these are special or gone in certain groups)

so bones (BONES!!!!)

so the pelvic and jaw bones in a metathere are different than in eutheres (we will talk about them next teehee) they do not have a rounded angular process and it's instead spiky (here's a picture of a possum jaw for reference)

There are also extra openings in the back of the pallet and a smaller brain case their teeth are funky too! They have an extra set of incisors.

so I mentioned their funky pelvic bones but what I mean by that is their reproduction is wacko. so like monotremes they have a cloaca and not a vaginal and anal opening. this is why they're "in-between beasts" they have traits that are similar to both ends of the spectrum.

speaking of reproduction their cloaca is subdivided and they will hold eggs internally with a specialized membrane. this membrane surrounds the fetus more than an egg would with a floating placenta surrounding the fetus unlike in us this placenta isn't attached to a uterine horn. Their reproductive structure is also loopy... I'm not kidding look at this shit- this is a kangaroo reproductive structure

WEIRD! They have a pseudovaginal canal which is only there for birth and is part of the cloaca also keep an eye on that second uterus ill get into that more with kangaroos specifically

and it's only in females male reproductive structure is normal

their young are always born underdeveloped. they have an extended lactation period because of this with that special changing milk we mammals have that will deliver the perfect amount of nutrients needed.

so the babies are born super early but those ungrateful little turds have the immediate responsibility to get THEMSELVES into their mother's pouch. Mamma can't help you do everything little Joey.

I need to expand on this because it's fucking INSANE ok so like I said they are underdeveloped and I mean like VERY underdeveloped as in they do not have a full heart or brain yet!!!!! their lungs are just sacks and they don't have a jaw but they DO have a tongue and arms that they use to pull along their mother's hair to get to the milk. again- mama ain't helping you.

left: me holding the fox squirrel's upper half in my hands for comparison

right: same photo but zoomed out you can see the skinned carcus in the bottom right corner

you'll also notice there are bloody tissues and a bag of snarge behind me (snarge is basically the guts/remains of an animal that's the actual term for it I didn't make it up I promise)

(side note: her head on top is not supposed to be that flat her skull was unfortunately crushed and shattered into quite a few pieces)

so when skinning an animal first you make a ventral cut from the midpoint of the stomach to the genitalia

I am really bad at this part.

I accidentally cut into the muscle lining holding together all the guts and innards this isn't a huge deal as you can just sorta pull them out and set them aside since I didn't need the carcus for future specimen mounting. So that's what I did I took the snarge out and set it aside so I didn't have large intestine sticking to my fingers

the problem that occurs when you do this though is you open up bleeders the body cavity will start to fill with blood as the specimen thaws (they are kept in a freezer until skinning NOT formadahyde or other embalming chemicals) and there's really nothing you can do about it so that's why there are bloody tissues I basically re-stuffed the squirrel with paper towels so I didn't get blood all over the pelt

ok so on to skinning I have done this one other time with my lovely little mouse corn dog (I'll explain)

after you make a cut and DONT fuck up the guts like I did you can start skinning which is honestly way easier on a squirrel than it is on a mouse (who would have thought)

you start with the hind legs and you pull the meat out all the way to the ankle joint and then we cut right at that joint to keep the foot bones intact connected to the skin some people will take these bones out but we don't just to make it easier on us once you have both legs out you pull all the bones out from the tail (you basically deglove it it's kinda cool to look at after) and then you pull the rest of the skin off like a jacket until you get to the arms (follow the same steps as the hind legs) and the head

the head in complicated once you get to this part you have a lot of things to keep in mind- the eyes, ears, nose, and mouth and you must keep as much skin as possible in the eyelids and lips while keeping the ears completly attached

it's very difficult... also TW for gore in the next photo

so corn dog

(jumpscare lol)

Corn dog is a little different thus mouse was prepared the same way as I just described however we mounted her to become a study skin

once she was skinned we made basically a tube of cotton to stuff up in there and sewed her up she looked like a corn dog- hence the name