Hacker News new | past | comments | ask | show | jobs | submit login
Cat Gap (wikipedia.org)
315 points by benbreen on Oct 16, 2020 | hide | past | favorite | 48 comments

It is essential when we look at deep time, or any sufficiently high-dimensional and detailed time series, to remember that we are only looking at a tiny slice. We always like to talk of "the tree of life", which might mislead folks into thinking that we get a clean cross-section of every branch of some high-dimensional tree. But, in truth, what we get is more like a tiny wedge cut out from a beanstalk with many central vines; we have only small leaves and cuttings from a mighty thick overgrowth of life.

Very true! I was also fascinated to find that it wasn't uncommon in the fossil record to have evolutionary lineages of species branch and later recombine. See: https://theconversation.com/dna-dating-how-molecular-clocks-...

> DNA holds the story of our ancestry – how we’re related to the familiar faces at family reunions as well as more ancient affairs: how we’re related to our closest nonhuman relatives, chimpanzees; how Homo sapiens mated with Neanderthals; and how people migrated out of Africa, adapting to new environments and lifestyles along the way. And our DNA also holds clues about the timing of these key events in human evolution.

Also, some of the numbers don't seem that big in context. But this situation is 7 million years - plenty of time for evolution to make lots of changes! It just doesn't seem like that big of a gap when we talk about hundreds of millions of years.

The scale is astonishing.

In a much more recent, much smaller gap, horses originated in North America but died out there, only to be later reintroduced from the Old World.


> "The evolution of the horse, a mammal of the family Equidae, occurred over a geologic time scale of 50 million years, ... Much of this evolution took place in North America, where horses originated but became extinct about 10,000 years ago."

Yep. 7 million years is a little under 0.2% of the age of the earth.

Although the first 20% were useless in terms of life.

Reminds me of the awesome board game “evolution: climate” [0]

The game was codesigned by a climate scientist, you evolve animals designed to thrive as the climate changes. Adding a carnivore (cat) changes the game and brings quick gains eating other animals but when the climate shifts and carnivores have nothing to eat they die first.

Large chunks of the game are often played with no carnivores (cats) as other strategies outperform.

Great game to better understand evolutionary dynamics.

[0] https://boardgamegeek.com/boardgame/182134/evolution-climate

"Evolution" has a bit of a problem with carnivores. It's easier to protect against carnivores than to build a cost-effective carnivore. You need to pay 2 cards to have species that can eat another species (one for Carnivore trait, one more for +1 size), but only 1 card to negate it with size increase. In my experience buidling a carnivore involves walking a thin line. It's quite easy for other players to counter you and your animal will go completely extinct. In natural world animals can still prey on eggs, juvenile or sick individuals. Evolution is a bit binary.

The reality of “adding horns” or “scavenger skills” to an animal is that’d take thousands of years. So I saw each round as thousands of years at a time, from that perspective I think it’s realistic, carnivores are highly effective until they loose supply.

I suppose it speaks to the benefits of being an omnivore like us.

Or you need to be clever and restrained with it.

For instance, in a 1 vs 1 scenario - and I mean species, not players - it plays out more less like I outlined it above. But the equation changes if another player has 2+ potential prey species. Then he has to react by spending 1 card for each species he has. Just change your expectations - your goal doesn't have to be wrecking other players. Just exploit abundance of vulnerable species.

Also, I have Evolution but no Climate (there's no localized version). I imagine it may be possible to play smart and use predators to push players into bigger sizes, then change climate to hot. For unfamiliar people - in the game, big animals overheat easier, while small animals struggle with cold.

>The game was codesigned by a climate scientist

How is a climate scientist qualified to codesign an app? I thought you had to be a registered software developer to do that! ;)


Oh I see where you’re going but to throw cold water it’s actually a board game :P

Is there confounding factors here such as size, weight, skeletal composition/dimensions, and/or even day to day patterns that could account for this?

Just sort of strikes me as absence of evidence not evidence of absence scenario after reading the article.

There are a few ways that one could reason from absence of evidence to evidence of absence, and that has a lot to do with what other kinds of fossils (if any) we've found in the same area in the same period.

One possibility is that cats found themselves in relatively dry areas where their remains would be picked apart by scavengers long before any fossilization could take place. The article mentions that forests turned into savannas at the time.

On a less serious note, perhaps the cat gap occurred when cats temporarily lost their skeletons and became fully liquid, or at least cartilaginous like sharks. Don't we all know how flexible they are? :)

Cats used to be the #1 predator of human ancestors.

Oh, how the tables have turned now we... spend our time and money feeding them and caring for them for nothing in return? Hmmm.

I get cat love in return -- a cat purring in my lap or next to me in the bed, and keeping me company when I am (was) doing school homework. Someone who wants to be nearby, chews on the pencil I'm writing with, falls asleep on the book I'm reading or writing in (making it not easy to turn to the next page).

Yes the tables have turned

They make great pets, they do their own thing until they want to spent time with you, I work from home and they keep me company, I generally have one asleep snoring on the chair behind my desk and the other either asleep on my lap or asleep under the monitor.

It's a more effective strategy. They can only eat one human once. This way they can be parasites of a human for years.

Remember, parasites: killing your host is generally a bad strategy.

How did people figure that out?

Ever since the invention of writing, the #1 predator to humankind has been other humans, so we must go back to the time before written records to get to a time when cats were the #1 predator. My question is, in the absence of written records, how did the people of the current age determine the rate of death from the various predators?

Maybe you mean the #1 predator not including other humans?

Predator as in eats you for food, not metaphorically.

I was not writing metaphorically.

Maybe I was unclear because I was trying not to cause offense.

My question is, How would anyone know that there was a time in human history or prehistory when cats were the #1 predator of human ancestors? (I assume he means the #1 killer of our ancestors that eats us for food.)

"Because of skulls with jaguar-like teeth marks" @29athrowaway wrote nearby in this thread: https://news.ycombinator.com/item?id=24807745

maybe I don't get your point (in which case, ignore me), but couldn't you just count the number of deaths by each predator? i.e. count the number of human skeletons with cat teeth stuck in their bones?

Those cats would not have fit into a typical Amazon box nor would they have been considered a tasty snack by a passing eagle. Size matters.

Do we know that? Why not bears? And do we know if attacks on humans were common?

One factor against bears being #1: Bears are not obligate carnivores, i.e. they can survive on fruits and vegetables. Cats cannot.

Because of skulls with jaguar-like teeth marks.

If you have a link, it'd be interesting to read. I websearched a bit but found only current time articles about jaguars

We have so few bones and skulls from back then that it is impossible to conclude anything.

does that page (which I seem unable to authenticate and edit) have a mistake, when mentioning the dental morphology of "Canidae" when "Felidae" was intended?

I looked at the cited paper[0], and I'm not sure the article author has correctly summarized its findings. As I understand it, the paper says "cyclical climate change probably caused this pattern of extinction->re-evolution (van der Hammen cycles)" and it points to overlapping changes in the geologic record (including canids and their teeth) as evidence of that claim.

I can't see anywhere where the article says "changes in canine dental morphology caused the cat gap."

Edited to say: oh derp, I only looked at the first line of the article - there's a discussion of that connection further down in the article, although it says in the summary that the connection is disputed.

[0]: https://link.springer.com/article/10.1007/s00114-002-0392-1

No, they're saying that dogs evolved to fill the niche usually occupied by cats. Rapid change in dog teeth becoming more suited to eat things that cats eat says something about the presence or absence of cats in the same environment.

No. From later in the article:

> During or just prior to this "cat gap," numerous caniform species evolve catlike features indicative of hypercarnivory, such as reduced snouts, somewhat enlarged canines, and fairly extreme reduction of their crushing molars.

They propose that Felids were pushed out of their hypercarnivorous niche by Canids as evidenced by changes in Canid dental morphology from this period.

I just asked my cat about this "cat gap" and he didn't have anything to say about it.

He's back to quietly snorring while sleeping on my couch, after his morning was filled with staring at birds outside, eating and taking a hell of a dump in his toilet.

Hard to believe he's got anything in common with the predators we are talking about here.

Common housecats that are allowed outside are some of the bloodthirstiest predators on the planet.

They can kill up to 200 animals per year, despite being well fed and cared for. They're doing it for sport essentially.

They will hunt and kill common shrew for example despite not eating them. They'll eat mice and birds, but shrews they kill just for the hell of it.

> some of the bloodthirstiest predators on the planet

Present company excluded, of course. A typical human "sports hunter" can easily kill a lot more than 200 animals. And if you count all the animals that die to feed us or are simply accidental casualties of our infrastructure and resource extraction... well, the mind boggles.

Animals who die to feed us aren't really relevant, are they? These 200-ish animals killed by housecats are on top of the food they're already receiving at home, which is made from slaughtered animals.

A sports hunter who doesn't eat their kills but only hunts for fun is an apt comparison, but do they really kill 200 animals per year? That's more than one every two days. Typically that would be a weekend hobby and even if they went hunting 52 weeks of the year that's almost 4 kills per hunting weekend. You really think that's plausible (or even legal, given restrictions on hunting)?

Plus, hunters tend to eat their quarry.

The main exception is probably people who hunt feral pigs in Texas, but those are just an ecological menace to be exterminated.

Isn't this what we wanted from cats historically?

Yeah, but this behaviour is not really bred into cats the way we've bred behaviour into dogs. Cats and humans is more of a mutually beneficial arrangement where we get pest control and they get shelter and a steady food supply.

They kind of just moved in with us several thousand years ago and stuck around because it worked out well for them.

I'd like us all to remember that for some time, no matter how short, Cat Gap was #1 trending on Hacker News.

Cats have domesticated humans because they are curious about many things including their origins, and lacking opposable thumbs to wield the tiny brushes, they never planned on doing paleozoology on their own.

They're tiny tigers we keep in our homes.

Slow news day or the internets favorite animal asserting it’s rightful place. You be the judge.

I'd guess that a decent percentage of organic traffic is just photos of cats. (The rest is another synonym of cats)

"All modern carnivorans, including cats, evolved from miacoids, which existed from approximately 66 to 33 million years ago."

Say no more.

The cat gap fits a pattern with Americans just not having the numbers. In time this evolved with the bomber gap and the missile gap:


Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact