I've been here and to a few other, equally spectacular sites in this general part of Colombia. They're well-known among local people, but some are VERY hard to get to (freight or chartered plane to a community completely unattached to the rest of the country by road + hours-long boat journey + hours of hiking).
They can be quite sad though, e.g. the relatively newer images depict colonization encroaching upon the region - horses (introduced by the colonists), swords, and scenes that appear to show imprisonment of people.
The "relatively newer" images you refer to seem to be nearly 12,000 years newer than the images mentioned in this article. They're likely from a different culture entirely.
The images are of various ages. This article describes the subset that are the oldest, but there are newer ones mixed in. In some places you get layers of them, where you can see that the older ones were drawn over. They can estimate how much later they were added based on the presence of animals and objects that did not exist there 12,000 years ago.
It's true that there's a huge gap in time between the earliest paintings and the newer ones and so some aspects of the culture probably did change. But the area has been continuously populated for millennia.
I'm not positive what GP meant either, but if they were talking about horses, that is mentioned in the article as being there about 12,000 years ago, which is significantly before colonization that first GP mentioned as having brought horses to the area:
> the rock art shows how the earliest human inhabitants of the area would have coexisted with Ice Age megafauna, with pictures showing what appear to be giant sloths, mastodons, camelids, horses and three-toed ungulates with trunks.
Apparently, there were horses in the Americas, but they went extinct about 12k years ago, along with the other megafauna.
What I understand is that different images could have been made in multiple time periods, from the first inhabitants up to today.
Blaming megafauna extinction on humans aligns with current misanthropic fashions, but rapid global warming at the end of the last ice age is a far more likely culprit.
https://www.nature.com/articles/s41467-021-21201-8
I don’t think it’s very credible to conclude the disappearance of both large herbivores has nothing to do with the arrival of a new, exceptionally adept and general apex predator.
Do you know when the megafauna of Madagascar went extinct? Right around the arrival of humans. What about New Zealand? Shortly after the arrival of humans. In every historical, known example of human introduction to a new ecosystem, most animals over 50lbs get eaten.
It's also interesting that essentially none of the native animals in Africa are domesticatable -- I think donkeys are the one thing we managed to domesticate there, most everything else was brought back from other continents.
Animals you'd think would be basically like other species we've domesticated, like zebras or gnus, take a strong "fuck you" attitude towards people and have resisted modern efforts to domesticate them.
So NA megafauna had no problems with wolves but people come along and it’s game over. Still not buying this. Why did horses die out but not bison or deer? How did mammoth go extinct while elephants didn’t when elephants faced more technologically advanced humans over a longer time period? Just doesn’t add up.
> but rapid global warming at the end of the last ice age is a far more likely culprit.
Firstly, your linked paper is focused on North America, so we can't say it's also applicable to, say, the extinctions of Homo floresiensis and Stegodon florensis insularis that correlate rather well with the arrival of modern humans.
Secondly, it repeatedly refers to global _cooling_ through the Younger Dryas Event. Just to clarify.
And tbh, claiming the overkill/big black hole hypothesis is merely current fashion is overly simplistic. It was described in the 60s based on available data, and hey, we're getting better data now, so yay, science is incorporating new data, like we expect.
And I'll note that the data points for human predation of megafauna used in that paper are likely to change also with time, so who knows how correct that paper's conclusions will be in another 20 years?
I don't see why "it was probably both" shouldn't be the default position. We know humans hunted megafauna, but like the fossil record, we know that only some evidence will be preserved, and only some of that evidence has been found.
But logically, both environmental change and the introduction of a novel predator (and other novel predators that predator may have brought with them) are bad for populations of species which a low replacement rate.
Kākāpō are a very good example. Human settlement brought habitat loss, causing their numbers to decline, and their breeding success rates to drop (and they were slow breeders to start with) as the more clement habitat was modified by humans, thus pushing them into areas with lower productivity.
But what ultimately pushed them to nearly going extinct was the introduction of very effective mammalian predators (mustelids). They had evolved for a land where the only predators were avian and sight based. So they became flightless because no point in flying away from danger when the danger was flying above you, and they developed cryptic colouration, they'd freeze when they sensed danger and became nocturnal. And most importantly, they used scent in lieu of dramatic colours to find each other in dense forest in the breeding season. No harm there, because raptors hunt by sight, not scent.
But being a smelly bird who is camouflaged and nocturnal and stands still, is no defense against ground predators who hunt by scent and quite appreciate not having to run after you.
I have the diaries of an explorer in the 1890s who would eat five kākāpō for breakfast, they were that easy for him to locate using his dogs, within 80 years of his parrot based breakfasts they were extinct on the mainland.
But yeah, habitat loss reduced their range, then human hunting reduced their range, then feral dogs and later cats reduced their range. But they were still around in decent numbers.
Then mustelids were introduced, and that was the tipping point, but only in the context of the prior stresses.
So for megafauna, hunting pressure places a population under stress, especially in species with a low replacement rate.
Climate change and the resulting changes in the ecosystem also puts populations under stress.
Maybe one of those stressors was survivable, but probably not both.
And for some megafaunal extinctions, especially on islands, it's pretty obvious humans were the deciding factor. Maybe not through hunting, just habitat loss could be sufficient (e.g., elephant bird), but often habitat loss went hand in hand with intensive hunting (e.g., moa)
What comes with people migrating to new environments? New diseases.
It’s bizarre to me that hunting is the “regular suspect” in so many imaginations of the far past when the diseases transported by humans and their animals was almost certainly as substantial a factor in the far past as it was more recently.
Actually was thinking on this, I suspect you're right that this is another potential stressor that should be considered.
Not so much diseases from animals brought by humans, but rather diseases/parasites from related animals who just mosied onto and sometimes over Beringia of their own accord.
E.g., wooly mammoths on the Eurasian steppes and American mastodons spent a lot of time developing in isolation, they could've had their own diseases they'd evolved to resist, then Beringia arises from the seas, and 100 years later, a mastodon catches the Mammmoth-flu or something.
From what little I understand, some of the N. American megafauna have been shown to have limited genetic diversity due to small founder populations, which we know can increase the vulnerability of a population to a novel disease.
I'm wondering how you'd be able to prove or disprove this though, maybe coprolites? Googling this briefly turned up this amazing website with the even more amazing tagline "#1 for fossilized #2"...
I don't believe there's any clear evidence for this theory, though that doesn't mean anything. Die offs from disease don't really leave anything in the fossil record. But it's hard to favor a hypothetical explanation when there's other theories with at least some data supporting them around.
Domesticated? Human beings back then would have been a walking menagerie of pests, right? Seeds and plant matter, mice, mites, flees, pets, and yes if they managed to travel with livestock, them too.
All of which we know today are vectors for the spread of disease.
I have zero expertise to comment on what a primary contributor to population declines might’ve been for any given animal, I just find it fascinating (and baffling) that those who are experts seemingly ignore something that is undoubtedly a contributing factor.
As others point out this is of course understandable, because the story is less compelling. The image of humans with spears tracking down the last wild beast is one imaginations can’t resist. The image of slowly dying and decaying beasts, less so.
"While genus Equus, of which the horse is a member, originally evolved in North America, these horse relatives became extinct on the continent approximately 8,000–12,000 years ago. In 1493, on Christopher Columbus' second voyage to the Americas, Spanish horses, representing E. caballus, were brought back to North America, first to the Virgin Islands; they were introduced to the continental mainland by Hernán Cortés in 1519. From early Spanish imports to Mexico and Florida, horses moved north, supplemented by later imports to the east and west coasts brought by British, French, and other European colonists. Native peoples of the Americas quickly obtained horses and developed their own horse culture.[5][6]"
your comment makes it seem like colonists reintroduced a native species (idk if that was the intention, but that’s how it reads), when in reality the horse species that were once native in South America was quite different from European Horses.
It also makes it seem like their extinction was due to human action (again, idk if that was the intention), but it also could’ve been due to climate change.
The key part from below is "Quaternary extinction event of most of the Pleistocene megafauna that is widely believed to have been a result of human hunting pressure."
>Fossil evidence indicates that mastodons probably disappeared from North America about 10,500 years ago as part of the Quaternary extinction event of most of the Pleistocene megafauna that is widely believed to have been a result of human hunting pressure. The latest Paleo-Indians entered the Americas and expanded to relatively large numbers 13,000 years ago, and their hunting may have caused a gradual attrition of the mastodon population.
The Mormon church believes Tapirs are what were being called 'horses' and what pulled chariots and such, as an apologetic way of covering the fact horses weren't on the continent, but Joseph Smith never knew that.
Practice algorithms and read about software design in your spare time. Apply to tons of companies, be prepared to be rejected from almost all of them, and to be asked questions that you have no intelligent answer to. Remember what they asked you, learn the problems you got wrong, and repeat. It may be brutal and embarrassing at times but if you keep at it you will eventually get a job. The only thing I can say about maintaining any sense of morale is to take some pride in the fact that you’re pushing yourself, and that tons of people have had the same shitty interviewing experience but gotten through it and realized it was 1000% worth the pain.
the leetcode/algo question stuff is mentioned here on HN alot but I've never gotten to the point where a test was actually offered to me. will start practicing though and hopefully an opportunity pops up.
If you're not getting calls, it's your resume that is bad. That either means the format, or the content. Seems to me the only change to the content that you can make is working on and advertising well written open source personal projects that your interviewers can see, or contributing to large open source projects.
Your resume should be exactly 1 page long, and have something that stands out (company worked for, open source contributions, volunteer work.. anything that makes it be different).
If you have worked for decades, write "over 10 years experience" :)
Bullet points are good, long sentences are bad.
Listing tech/languages is a good idea if you can list a lot of real stuff. No one cares if you used ms word.
It should be 1 page!!! Don't cheat via small fonts. People can look at your linkedin if they need to know all that crap.
In that case, you might want to have a friend/acquaintance with a job like what you want to review your resume and give you feedback on that and a first round-style interview. If you don’t know anyone who can, read over resumes on linkedin, and pay close attention to the language used, and to the extent that it’s relevant to your work try to mirror it. Try to be direct and confident about what you know/don’t know during the interview, and try to at least learn how to talk about technologies that touch what you’re more expert in.
There’s a time and place for asking explicitly for feedback - it can give you 1:1 time with a mentor, and make you look engaged with your role.
But IMO more important is being able to see/hear feedback day to day without having to ask. Try to notice patterns in code review comments, which conversations you’re having trouble participating in due to lack of seniority in that area, which of your suggestions fall flat, etc. and don’t be afraid to ask lots of questions (nondefensively!)/do some research if you don’t understand why you’re getting a particular reception.
I'm not perfect about this but one experience in particular helped me.
I was a new employee doing on-the-job training for an even newer employee, while we were trying to meet a deadline. We were the only two people working on this project, in the middle of rural NM, out of cell range, and having to improvise. He kept making suggestions and I kept explaining why they wouldn't work. Suddenly he point-blank asked me why I said no to everything. I had a moment of clarity where I realized that I didn't even want him to be right, for no good reason except my ego. I apologized, horrified, and have been forever grateful for the wake-up.
After that I started to notice that pattern elsewhere. The best way I've found to interrupt it is to ask myself "what if they're right" and/or "in what way might this person be right that I may not have considered"?
> The best way I've found to interrupt it is to ask myself "what if they're right" and/or "in what way might this person be right that I may not have considered"?
There's also a great question to ask yourself even before those: is it worth it?
A lot of times just ignoring improvements you can see/sense is the right call. Every time you bring up a suggestion (whether it is to a teammate or to yourself) your are affecting the environment in ways that can compound. For instance:
- You may break the creation flow, interrupting the far more important "advancing to the greater goal" by perfecting a middle-step that matters much less and can be easily corrected afterwards if need be.
- You are de-valuing your future suggestions/feelings, because the more stuff you bring up, the less weigh they get in the long run.
- You risk lowering your teammate's confidence / degrading your relationship (just like you were doing in your story).
If you are one of these people who just cannot "let something go", what you can do is write that thing down. Just make a note "revisit X thingy" and come back to it later when the rest is done/clear. This should allow you to actually move forward towards the "big picture" with a clearer mind (i.e.: without having that thread stuck wasting effort on what you just "ignored").
Finally, if the issue is important enough that it requires solving to advance, another great attitude is to ask yourself "how can we make this work?" instead of stopping at "this doesn't work because X".
Propose things even if you can see they don't completely solve the issue. This fosters a collaborative building attitude where you can fill in your teammate's blanks and vice-versa. Simply stating what doesn't work shuts down idea sharing and limits the team's creativity to that of the individuals, instead of the (oftentimes much greater) sum of the team.
> If you are one of these people who just cannot "let something go", what you can do is write that thing down.
I used to be hypercritical in code review, but I started instead just taking note of small things that didn’t really matter and fixing them myself during downtime.
I feel a little mixed on the solution. On the one hand it has the junior devs less afraid of me and more willing to actually ask for help. On the other hand they’re not learning from some of their mistakes. Life is full of trade offs though.
I have the opposite problem. I always struggle with frequent interrupts wondering "what if I am wrong?" and I fail to move forward without utmost conviction.
Nowadays I try to tell myself that no one is perfect, especially me. Expecting oneself to be correct all time is actually egoistic even though the end result turns out to be being humble and having self-doubts. To fail or to be wrong is natural. My boss even encourages me to fail sometimes, to be comfortable with the possibility failure. I am not saying that I am doing these things by default now, but at least I make it a point to try.
I'd also suggest trying to harness the "what if I am wrong" so you can use it to your advantage - it sounds like the kind of attitude that could make you excellent at testing.
If you turn it into a curious question instead of a self-judgment, it may help identify ways to test something that would give you full confidence that it works. Which is a very valuable skill to have.
I have a similar experience. A gf first told me that I was too negative, and then a friend when working on a side project. Both event made me think a lot about it. I’m still working on it but this really makes me think that feedback, as much as I hate receiving it, does improve people.
Every time I catch myself thinking "wrong" about a position or solution someone states, I remind myself that my thinking is probably the only wrong thing here. I displace that negative behavior with curiosity.
That means, trying to explore what the other person might know that I do not. What data or knowledge I am missing could have lead that person to the view or position my fast thinking labeled as wrong?
Rarely, it does happen that I had more context or data, but those are outliers. In general, by adapting my behavior from thinking "wrong!" to thinking "what does this person know that I do not?" I am able to have way more productive conversations.
I don't think negative comments are obnoxious. I vastly prefer them to being a naive fan of everything. I believe this negativity is just being realistic and isn't a result of an inflated ego or insecurity. Reality is that people are often handed a bad deal and it is endemic in the tech industry by now.
There is a difference to saying no to everything of course, but part of the negativity in tech is that it is earned.
Thank you for that post. Thats personally something I probably needed to hear and make a consideration to address what is, frankly, a negativity problem.
> Out of the people I had hired at my last startup:
> 12% of hires where exceptional hires (I would instantly hire again)
> 42% of Hire were good hires. (I wouldn’t hire again but they did a fine job)
> 29% of hires were bad hires. (They didn’t do a good job and were eventually let go)
> 17% of hires were very bad hires (They had a negative effect on the company culture and other staff)
These seem like extremely poor numbers. I haven't hired a ton of people but all of them have been excellent, though some that I was peripherally involved in hiring have been just good. I'm curious what other people feel that their ratio is.
This could roughly be saying half of hires are below average, and the distribution is bell shaped (or triangular to a first approximation). For many jobs, below average can be equivalent to bad.
If you have money to spend, or can wait to hire, you can beat the averages. I've hired a fair amount and done well too, but only by refusing to hire anyone if there are not suitable candidates that applied, which can burn a lot of political capital (your boss sees you've spend x time and money and had y applicant and z interviews and you refuse to hire anyone).
Employees aren’t scratch tickets. The on-boarding, training, engineering culture and practices all contribute strongly to whether the prospective employee will turn out to be excellent or not. (I leave it to your judgment to guess how a place where 42% “were good hires, did a fine job, but I wouldn’t hire them again” falls on that spectrum.)
Yeah, it sounds so bad that it’s probably made up. It implies that the company has 46% turnover or firing rate (29+17), but average turnover for tech companies is 10%-15% [0].
I interpret it as a pre-defensiveness. Whereas some people admit they wouldn't have the guts but respect people that do, others are trying to convince themselves that the choice they'd make would be the right one.
