#mammal -> primate -> human

[julie-su]

LADIES AND GERMS. WELCOME TO GRUNCH WEEK-FORTNIGHT 2024

[vickysaurus]

Let's take a closer look at the hominin skulls in the Senckenberg Museum's human evolution room. Keep in mind this is not a linear progression through our ancestors, and more like a bunch of closer and more distant cousins.

The first one, Sahelanthropus tchadensis is seven million years old, and may very well not be a hominin at all. I've always leaned towards the hypothesis that it's a gorilla relative, not one of ours. No matter which branch of the apes it belongs to, it lived not long after the time the human-line (hominins) and the chimp-line separated, and possibly even before that point!

Ardipithecus ramidus, the first hominin from where we can start making a fairly decent family tree of our relatives. Before this point, 5 million years ago, hominin fossils are very rare, fragmentary, and difficult to assign. One of the most interesting things that does seem to emerge from these early fossils is that we have walked on two legs for a long time. Maybe even so long that our common ancestor with the chimps and bonobos did it!

Lucy represents Australopithecus afarensis, who shows up at this point (3.3 million years ago).

Australopithecus africanus, the Taung child to be precise. We're about 2.8 million years ago at this point. Australopithecines must've been such fascinating creatures.

Homo habilis, the 'handy man', named that way because when they were discovered they were thought to be the first humans who used tools. Since then, Australopithecus tools have been found, and tool use by many different animals has also been documented.

Homo rudolfensis, a population of humans who lived at the same time as Homo habilis and were notably bigger and a little brainier. Does it warrant being its own species? That depends who you ask. Splitting vs lumping is a point of contention in almost every group's biology, and it can run especially high in the field of human evolution since hominins are A very high profile and important fossils that directly relate to our own origins, and B an extremely tangled group that seems to have produced loads and loads of isolated populations and subspecies that regularly migrated all over the place and had frequent interbreeding events. Personally I tend to come down on the side of lumping them into a few major species.

Paranthropus boisei. These were basically a separate lineage of australopithecines, quite different from our own ancestors, who continued to do australopithecus things until quite recently. They were very good climbers and seem to have returned to the trees.

Homo ergaster, either a close relative or a synonym of the more famous Homo erectus. This is the point where we got really brainy, probably figured out how to make fire ourselves, and spread from Africa to Eurasia.

Homo heidelbergensis. Homo erectus and its many subspecies spread all over Africa and Eurasia and existed for well over a million years. As time marches on and evolution did its thing, we eventually start calling the ones in Africa Homo heidelbergensis. They were quite tall, positively enormous compared to little Lucy a few million years back, and they too joined in the human migrations out of Africa. From the H. heidelbergensis who moved into Eurasia we eventually get neanderthals and denisovans, while Homo sapiens evolved from the heidelbergensis populations in Africa.

And there's the neanderthals! Large-brained and creative (the first known cave paintings belong to them and they buried their dead), they were likely quite different from the brutish image we often get from them. Rather than truly dying out, their populations eventually merged with the larger Homo sapiens population once they migrated out of Africa, leaving our modern genes with a couple percent neanderthal DNA.

Homo sapiens. And that's us! Not so much the last remaining branch of the human family tree as much as several of the separate branches ended up coming back together and weaving into a single bigger branch.

And then there's these little guys, Homo floresiensis! Probably originating from a Homo erectus population that ended up on the island Flores, insular dwarfism ended up making them grow quite tiny. On their isolated island, they remained until about 50000 years ago.

[biologist4ever]

[critter-creature-or-beast]

Submitted for classification by @cellobuster

[michael-rosskothen]

Homo Habilis and Mammoths

[judgingskeletons]

Judge

[ID: a person in a full body skeleton outfit. Included is a bone where a penis would be, which extends past the knees. End ID]

DICK BONE. 1000 POINTS LOST FOR DICK BONE.

Leg bones look decent. Pelvis is weird especially the very smooth and fused sacrum. Sacrum doesn't connect to lumbar spine. Not enough ribs. Not quite got the shape on the sternum and it's a bit wide. Humeri look like bad and backwards femurs -997/10

This made me chuckle, thank you

[miraphoenix]

I love this tweet because those fish are trying to beat the ever-loving shit out of each other, or at the very least trying to determine which one of them is the more dominant fish.

(ID in alt: A screenshot of a tweet reading “this is how I would kiss my fish wife if I was a fish and married”. This is posted above a photograph of two white fish pressing their mouths together on a blue background. End ID.)

The fish in the image are leucistic Helostoma temminckii, the kissing gourami. This 'kissing' behavior is generally understood to be an aggressive or agonistic behavior, depending on the analysis; basically, either a legitimate fight or a ritualized fight.

Mouth-to-mouth contact is not usually a sweet/kind/fluffy behavioral signal in fish.

Many cichlids also have a known behavioral pattern that looks like kissing; the two fish lock mouths and bite each other with flared fins, before the fight breaks off with the loser fleeing. (Sometimes the fight escalates, but a jawlock or mouth battle is usually only seen in the most pitched of cichlid combat.)

Sarcastic fringeheads (Neoclinus blanchardi) are another fish worth mentioning in a page on mouth-to-mouth combat or agonistic display in fish. A blenny that lives in various tubes, the sarcastic fringehead displays its frankly enormous mouth during territorial disputes with other fringeheads, with the pair first displaying mouth sizes. If that doesn't settle the dispute, the fish escalate to pressing the upper jaw against the other fish's mouth and pushing at each other; whoever has the bigger mouth and the greater endurance tends to win, and chases off the loser.

(ID in alt: A picture of two sarcastic fringehead fish fighting; they are long fish with large, triangular mouths in blue and green. Photo by Richard Herrmann. End ID.)

But yeah, if there is a picture or video of two fish in mouth-to-mouth contact? Especially if they're pushing back and forth at each other. It's probably not because they're displaying a pair bond, and they're probably not showing what a mammal would recognize as affection; they're almost certainly trying to determine who's the bigger/more dominant animal.

[rotationalsymmetry]

ok I’m definitely not reblogging because I don’t want to shame OP, but I just read a really weird read on vegetarianism and pet ownership.

I’m an ecologist. My opposition to meat eating isn’t about the sanctity of life; most animals eat at least some meat some of the time, some animals exclusively eat meat, animals can eat meat and also have a functioning ecosystem. Actually everything has to be eaten at some point, either via predation or after death via scavenging or decomposition. That’s how we recycle nutrients.

The reason it’s not great for humans to eat meat has to do with trophic levels and carrying capacity . There’s about an order of magnitude more zebras than lions. If humans want to live like lions, our carrying capacity (how many of us can exist without breaking everything) is lower than if we live mostly like zebras. This is complicated by exactly what biome you’re living in (if you live in the arctic, living like a zebra is not an option) and it’s also complicated by the way all industrial agriculture is unsustainable. There is a sense in which all industrial ag is just terrible and we shouldn’t be doing it, at all. But just like you can’t live like a zebra in Alaska, in practice most people can’t opt out of industrial agriculture. But industrial animal agriculture is about an order of magnitude (ten times) more unsustainable than skipping the animals and feeding people plants, so when people can eat plant foods or mostly plant foods — and especially when people can avoid beef/cow meat specifically — it’s … harm reduction. It buys us a little more time.

My impression is indigenous cultures that aren’t in places where eating plants isn’t viable handle this by 1. mostly eating plants, or maybe some combo of plants and seafood, and 2. having a bunch of rules around hunting and harvesting that include the idea of asking permission to take life. I have no idea what that looks like in practice, but I’m sure it makes sense to people who were raised that way. Point is, while vegetarianism is a cultural anomaly, that doesn’t mean that cultures that do eat meat think everything is fine with every way of killing animals for meat.

As a side note the reason I can coexist without conflict with meat eaters is I have a very strong ethic around the idea that each person is in charge of their own life and moral choices, and I’m kind of straddling the middle of an older worldview of “some things that are good to do are mandatory for everyone, and some things that are good to do are sort of above and beyond, and most people aren’t going to do them and that’s ok,” with vegetarianism being one of the above and beyond things, and a newer stoicism-based “whatever anyone else does is none of my damn business anyways.” That’s got nothing to do with seeing animal lives as less valuable than human lives — I think humans should be eaten too, by worms or bacteria or fungi after we’re dead, so that nutrients stay in the ecosystem — and everything to do with “I’ve got enough to handle with my own life and my own moral responsibilities, I don’t need to be running other people’s too.”

[princessmagichuman]

A late Father’s Day 2024 drawing of Princessnator, her husband, and their child.

OCs, Sona, and Art © Me

[vickysaurus]

What's better than this? Guys being dudes.

[bogleech]

Your regular reminder that wasps are “defensive,” not “aggressive,” since 100% of their fighting instincts are to make sure big mammals stay away from their babies. They want you to see their bright colors and know that they hurt super bad so you won’t be foolish enough to find the nest and eat the larvae, which big mammals have been doing for so long, it’s what selectively bred wasps to be that way to begin with. This does include primates, including humans, in fact bee and wasp larvae have been staple parts of the human diet throughout history and there are still places where specifically types of paper wasp are bred as food!

[froody]

I lay in bed at night and then remember that humans are a species of great ape most closely related to the bonobo and then I start to think about it really hard and think about how weird looking we are compared to every other primate and how weird looking we are compared to every other mammal and

[weirdnaturalscience]

I’ll start!

1. the clitoris is present in ALL mammal species, as well as many species of birds and reptiles.

2. the clitoris is mostly internal, much larger than you think, and capable of erection. It is made of the exact same tissue types as the penis. It extends from the head of the clitoris (external) all the way to the sides of the vaginal opening (internal), sometimes beyond. it also extends laterally.

3. the full, accurate anatomy of the clitoris is missing from most medical texts. Doctors who perform pelvic surgeries may not know where your clitoral nerves are, and may sever them.

4. most women cannot orgasm without clitoral stimulation, and yet many men expect them to. I suggest these men orgasm without penile stimulation.

5. Indian flying foxes have been observed engaging in cunnilingus, which increases the duration of penetrative sex. Non-human primates have also been observed engaging in cunnilingus.

6. Clitoral stimulation causes ovulation in some mammals for whom the clitoris lies inside the vaginal canal, suggesting an evolutionary function for the clitoris.

7. Some people like to hypothesize that the clitoris is vestigial, despite zero scientific evidence to back this up.

8. The scientific study of the clitoris has been severely impacted by misogyny. Misogyny is also evident in the lack of sex education on the clitoris, where it is often omitted or only discussed briefly.

9. The clitoris has over 10,000 nerve endings.

10. The clitoris is THE source of sexual pleasure and sexual function for 50% of our population.

[howlingday]

Ruby: Hey, Jaune, can you help me with something?

Jaune: Sure thing, Ruby! What's up?

Ruby: Well, I was just thinking, but we're both humans, right?

Jaune: Uh, yeah?

Ruby: Humans are primates, and all primates belong to the Mammalia Class.

Jaune: R-Right. Okay?

Ruby: And since we are both creatures classified as mammals, and nothing more, then it would only make sense that we should imitate what other creatures found in our classification by following the examples of said creatures found on documentary programs about naturalism topic, usually airing on TV.

Jaune: ...

Ruby: In other words...

Ruby: You and me, baby, ain't nothin' but mammals, so let's do it like they do on the Discovery Channel~.

Jaune: Do it again now~!

[mammalianmammals]

Camera traps from our karst surveys in Cambodia have revealed a whole host of fascinating species:

Long-tailed Macaque: Found across Southeast Asia, these primates are highly adaptable, thriving in forests and human settlements. They are opportunistic feeders, consuming fruits, leaves, and invertebrates. IUCN Red List Status: Endangered Sunda Pangolin: found in Southeast Asia. Sunda pangolins feed on ants and termites. They use their strong front claws to tear open termite mounds and ant nests, then use their long, sticky tongues to capture and consume the insects. IUCN Red List Status: Critically Endangered Mainland Serow: a goat-like mammal with a bristly coat and backward-curving horns, inhabits the Himalayas, Southeast Asia, and China. They live in forested, mountainous regions. IUCN Red List Status: Vulnerable

via: Fauna & Flora