What do you mean by "finish line"? Species evolve, they live for a while, they go extinct. Some species (crocodiles and sharks, for example) have survived for hundreds of millions of years, while others, such as earlier forms of humans like Homo erectus or Homo habilus, are only around for a million years or less. Environments change, selection pressures become more acute, predator/prey species change, and the species of interest either adapts/evolves or it doesn't, and goes extinct. That's the way of all things.

Couldn't understand the question clearly. Are you asking "though possibly they are fast runners, how they could be got extinct?"

Look at the numbers. They'd been around for a long time, surviving countless environmental changes, so what happened?

Extinction rate for large species is extremely large since humans became abundant.

@Remi.b That is not relevant to the question.

@AlwaysConfused No, I'm saying that they were a success story, yet something happened to them. Honestly, are metaphors foreign languages to you?

@JohnWDailey I don't understand the question then. Can you please try to clarify it? You gave examples of large mammal species that are now extinct. Your question seem to be "" It seems to me that many large mammals have recently gone extinct. Why is it so?" (The answer to which is in large part due to human activities). Did I misunderstand your question?

@Remi.b Look at the numbers again. They'd been extinct LONG before we existed. (200,000 years ago.) And don't give me Blitzkrieg theory, because that never made sense.

You are right, the dates definitely do not match with the spread of humans.

The extinction dates span over a very long period (31 millions years) which make me doubt you would find a single reason for their extinction. Have you read anywhere that these extinctions represent One of the great mysteries? Such reference would be helpful.

@Remi.b They all started out when the world was a jungle. The fact that they marched past the Grande Coupure means that they could thrive in a diverse variety of habitats and climates. By that logic, they should still be here in the 21st century, but they're not.

Do you have any rational for thinking they all got extinct for the same reason? Or do you have any evidence to suggest that there was at some point a sudden high extinction rate? My feeling is that you just cherry picked (it is easy to cherry pick without bad intention) some lineages that got extinct and expect some common explanation for them all.

@Remi.b Do you have an answer as to how groups who had survived countless environmental changes still bit the dust?

Species go extinct, there's nothing weird about it. Given enough time every single species on the planet now will go extinct.

@rg255 It's weird that they withstood every single change in the environment that Earth could throw them at.

@JohnWDailey first, regarding metaphors - not all people on the internet are from America, and, believe it or not, not all of them speak English as their first language, or as well as you and I do. Kindly refrain from harassing them. Second, what sort of answer are you looking for? You never addressed my first comment. Species can survive for a long time, then meet a challenge they can't overcome, and go extinct. It's not "weird", it's the way evolution works. Each of the species you mentioned likely has a unique reason it was no longer able to survive, which makes this question too broad.

@MattDMo I'm not talking SPECIES. I'm talking ORDERS and FAMILIES. They lasted long, so why didn't they make it to the finishing line?

There is no reason to think that all these lineages went extinct for the same reason. Maybe you should address the question of the extinction of each specific lineage in a separate post (as a post should include only a single clearly defined question). Also, it is not because a lineage survive an event of extinction that it would survive another one tens of millions years later. I am voting to close as too broad.

@Remi.b With three stars? That's quite a risk. Look, rodents had survived 56 million years of environmental change without problem. Carnivores had survived 42 million years of environmental change without problem. Afrotheres survived 65 million years of environmental change without problem. All our MODERN mammals had survived tens of millions of years of environmental change without problem, so why can't we ask the same of them?

@JohnWDailey there is no such thing as a finishing line in evolution. Species, families, orders, whatever are around for a while, some have survived until this day, some have gone extinct a long time ago. That's what happens. Asking why for eight different types of animals is off-topic on this site, as it would take 8 separate answers. I'm sure you can do a good job of finding out at least some hypotheses of why they went extinct when they did by spending some time Googling and reading the literature. Arguing isn't going to change anything.

@MattDMo Nor is waving a hand of dismissal acceptable.

@JohnWDailey I'll ask you again: What are you getting at? Why do you find it so difficult to accept that shit happens? Species, families, orders go extinct. These ones did. Other ones haven't yet. So what?

@MattDMo I asked a simple, straightforward question, and you treat it as some unbreakable enigma. We are talking about orders and families that had survived TENS of MILLIONS of YEARS of ENVIRONMENTAL CHANGES. By that logic, we should still have them today. But we don't--and THAT is the mystery.

@JohnWDailey did I say it was an enigma? No. I'm sure there are reasonable explanations as why they went extinct, and with some searching you should be able to find them. You are the person that won't leave this topic alone. Please take the tour and carefully read through the help center to learn more about the site, including what is on-topic and what is not, and how to ask a good question. This question is far too broad for this site.

@MattDMo I was the one who asked this topic in the first place. How else would I not leave it alone? The mystery is exactly that--a mystery. No "they just went extinct" excuse--natural human curiosity demands A LOT better than that.

@JohnWDailey I think it would be best that you calm down about this, you've had feedback from a number of experienced users that say this is very broad and off topic. No one here is trying to censor you or close questions for no reason, we all voluntarily give tine and effort to maintaining the sites standards and producing material. If the community gives feedback on your question it's safe to assume it's worth listening to (it's been given for a reason by people more familiar with the site than you) rather than arguing against it.

It's possible to speculate as to why certain species go extinct, but really the crux of your question is why does extinction happen at all. The answer is very simple, it just does - species fail to adapt to the prevailing conditions (changing habitat, changing predators, being shot, getting struck by a meteor).

@rg255 Careful with using "it just does" in your explanations. Most of us happen to know what you mean, and it's correct, but it won't help you convince someone of something new, and actually does come across as "don't question it". The portion after the dash should really be front and center, not an afterthought to make "it just does" plausible.

@Harrisweinstein I'm aware it's not great to just say it just does, which is why I explained why it just does

@rg255 If you're aware that it's not great to just say "it just does", then why did you do so anyway?

Can you please stop commenting excessively?

@Chris Not until I get an answer.

@JohnWDailey I didn't just say it just does, it's is followed by an explanation as to why it just does

@JohnWDailey you've gotten your answer from several different people, including myself. Extinction events happen for a number of reasons, the key one being failure to adapt. Numerous examples have been given. I'm going to suggest that this question be locked to prevent further commenting, because it is not useful.

may be the OP asking was there any big disaster that destroyed some successfully adapted animal groups.

@JohnWDailey Yes honestly and politely; metaphors are foreign language to me. Though in certain context (say a political cartoon or a chemistry cartoon) I could somehow crack the metaphor when the context is known to me. But since I do-not have any idea about these extinct taxa; I could not understood its actual meaning.

@JohnWDailey The questions is locked now, new comments are not possible any more. Please discuss this issue in the chat, the comments are not for extended discussion, so please stick to the rules.

@MattDMo The Cenozoic climate was not like the warm, stable Mesozoic. There had been a series of environmental changes at breakneck speed, yet the orders and families I listed endured tens of millions of years of it, and by that logic, they should still be here today. The fact that they were not is the mystery that needs solving. "Just because" is an excuse, not an answer.

This conversation has been going in circles for quite some time now, and I am not interested in pursuing it further.