5 ms·

Saber-toothed cats became inbred–and struggled to move–before they went extinct

71 points by gmays 3mo ago

Animats 3mo ago
Another predator that went through a genetic choke point. Cheetahs did, too.[1] Cheetahs survived, but they are so similar genetically that they get the same illnesses, and skin grafts between unrelated cheetahs are not rejected. [1] https://academic.oup.com/jhered/article/108/6/671/3836924 https://academic.oup.com/jhered/article/108/6/671/3836924
deleted 3mo ago
[deleted]
chrisco255 3mo ago
I think the study makes a giant presumptive leap to assume inbreeding was the cause of the higher-than-modern-human incidences of spinal tumors. It's irresponsible to assert this to be true instead of one of several possible explanations.
- Retr0id 3mo ago
  Seems like there's also a sampling bias, where the less able-bodied animals are more likely to get trapped in tar for scientists to study.
- icegreentea2 3mo ago
  The study and the summary do not "assume" that the cause was inbreeding. They both assert that inbreeding could be a cause. The article says "The team suspects these deformities and tumors indicate a lengthy history of inbreeding". The paper abstract says "possibly because of an accumulation of expressed deleterious alleles that caused disturbances in developmental processes". It's perfectly ok for scientists to write down and publish their speculation, as long as it's suffiently clear. I think it's quite clear in this case.
  - dimes 3mo ago
    An assertion without conclusive evidence is an assumption.
    - mythrwy 3mo ago
      They are not asserting a fact. They are asserting a possibility. Asserting a possibility is not an assumption.
  - deleted 3mo ago
    [deleted]
- webdoodle 3mo ago
  Yep. For instance it could be from higher cosmic ray penetration into the earth during the last geomagnetic excursion.
litoE 3mo ago
Wouldn't it make sense to assume that as the size of the population decreases, perhaps for external factors such as climate change, you are going to see more and more inbreeding?
morkalork 3mo ago
No worries, they'll evolve again. Like crab-form, it has happened multiple times: https://en.wikipedia.org/wiki/Saber-toothed_predator#Evolution https://en.wikipedia.org/wiki/Saber-toothed_predator#Evoluti...
NL807 3mo ago
I was always puzzled how these cats actually fed. These sabre toots seem to get in the way of feeding and chewing.
- zarflax 3mo ago
  I know I'd certainly be discouraged from feeding if I got the sabre toots.
- thaumasiotes 3mo ago
  > These sabre toots seem to get in the way of feeding and chewing. Why? They don't stop the mouth from closing. Presumably they don't stop it from opening either. Compare walruses, elephants, and pigs.
  - King-Aaron 3mo ago
    > Compare walruses, elephants, and pigs. Three animals that are well known for their apex predator hunting prowess
    - thaumasiotes 3mo ago
      Was the question more about ability to hunt, or ability to chew?
      - King-Aaron 3mo ago
        It goes hand-in-hand when you're comparing these kinds of animals.
        deleted 3mo ago
        [deleted]
  - NL807 3mo ago
    >They don't stop the mouth from closing. Presumably they don't stop it from opening either. That much is obvious. The question is how they get around sabre tooth without being a major obstruction to bite pieces of meat off. As for the other animals, Elephants mostly use their trunks to put food in their mouths. Pigs, their teeth are not that huge comparatively speaking and less of an obstruction, plus the have a very long snouts. Walruses, I have no idea how they manage to feed either.
conductr 3mo ago
If you watch predator behavior, they will always go for an easy kill. The tar pit provides those opportunities. Also, if these opportunities are routine enough and occur in a hyper local area, it’s hardly even hunting they become more like scavengers patrolling the area and perhaps defending it from competition. That said, it seems more likely to me cats near the tar pits just held the territory and became inbred from that. You can see similar patterns today around a junk yard. There will be feral dogs or cats that are living off the trash. They protect it from outsiders and inbreed. That’s if inbred is even the explanation. I think it’s also possible that weak or deformed cats may just prefer this site more than healthy cats as they are hungry enough to take the risk. So the population bias is inherently there through attendance. If cats are getting stuck in tar so frequently, it’s likely they knew going near it was risky. Healthy cats would hunt elsewhere and avoid the risk.
- asdff 3mo ago
  Tar pits are full of remains of many types of predators, not just saber tooth cats, after all.
- cineticdaffodil 3mo ago
  Also handicapped (by age or birth) individuals in nature are always squeezed into subpar territories where they then wither and sucumb

71 points by gmays 3mo ago

Another predator that went through a genetic choke point. Cheetahs did, too.[1] Cheetahs survived, but they are so similar genetically that they get the same illnesses, and skin grafts between unrelated cheetahs are not rejected. [1] https://academic.oup.com/jhered/article/108/6/671/3836924 https://academic.oup.com/jhered/article/108/6/671/3836924

deleted 3mo ago

[deleted]

chrisco255 3mo ago

I think the study makes a giant presumptive leap to assume inbreeding was the cause of the higher-than-modern-human incidences of spinal tumors. It's irresponsible to assert this to be true instead of one of several possible explanations.

Retr0id 3mo ago
Seems like there's also a sampling bias, where the less able-bodied animals are more likely to get trapped in tar for scientists to study.
icegreentea2 3mo ago
The study and the summary do not "assume" that the cause was inbreeding. They both assert that inbreeding could be a cause. The article says "The team suspects these deformities and tumors indicate a lengthy history of inbreeding". The paper abstract says "possibly because of an accumulation of expressed deleterious alleles that caused disturbances in developmental processes". It's perfectly ok for scientists to write down and publish their speculation, as long as it's suffiently clear. I think it's quite clear in this case.
- dimes 3mo ago
  An assertion without conclusive evidence is an assumption.
  - mythrwy 3mo ago
    They are not asserting a fact. They are asserting a possibility. Asserting a possibility is not an assumption.
- deleted 3mo ago
  [deleted]
webdoodle 3mo ago
Yep. For instance it could be from higher cosmic ray penetration into the earth during the last geomagnetic excursion.

litoE 3mo ago

Wouldn't it make sense to assume that as the size of the population decreases, perhaps for external factors such as climate change, you are going to see more and more inbreeding?

morkalork 3mo ago

No worries, they'll evolve again. Like crab-form, it has happened multiple times: https://en.wikipedia.org/wiki/Saber-toothed_predator#Evolution https://en.wikipedia.org/wiki/Saber-toothed_predator#Evoluti...

NL807 3mo ago

I was always puzzled how these cats actually fed. These sabre toots seem to get in the way of feeding and chewing.

zarflax 3mo ago
I know I'd certainly be discouraged from feeding if I got the sabre toots.
thaumasiotes 3mo ago
> These sabre toots seem to get in the way of feeding and chewing. Why? They don't stop the mouth from closing. Presumably they don't stop it from opening either. Compare walruses, elephants, and pigs.
- King-Aaron 3mo ago
  > Compare walruses, elephants, and pigs. Three animals that are well known for their apex predator hunting prowess
  - thaumasiotes 3mo ago
    Was the question more about ability to hunt, or ability to chew?
    - King-Aaron 3mo ago
      It goes hand-in-hand when you're comparing these kinds of animals.
      - deleted 3mo ago
        [deleted]
- NL807 3mo ago
  >They don't stop the mouth from closing. Presumably they don't stop it from opening either. That much is obvious. The question is how they get around sabre tooth without being a major obstruction to bite pieces of meat off. As for the other animals, Elephants mostly use their trunks to put food in their mouths. Pigs, their teeth are not that huge comparatively speaking and less of an obstruction, plus the have a very long snouts. Walruses, I have no idea how they manage to feed either.

conductr 3mo ago

If you watch predator behavior, they will always go for an easy kill. The tar pit provides those opportunities. Also, if these opportunities are routine enough and occur in a hyper local area, it’s hardly even hunting they become more like scavengers patrolling the area and perhaps defending it from competition. That said, it seems more likely to me cats near the tar pits just held the territory and became inbred from that. You can see similar patterns today around a junk yard. There will be feral dogs or cats that are living off the trash. They protect it from outsiders and inbreed. That’s if inbred is even the explanation. I think it’s also possible that weak or deformed cats may just prefer this site more than healthy cats as they are hungry enough to take the risk. So the population bias is inherently there through attendance. If cats are getting stuck in tar so frequently, it’s likely they knew going near it was risky. Healthy cats would hunt elsewhere and avoid the risk.

asdff 3mo ago
Tar pits are full of remains of many types of predators, not just saber tooth cats, after all.
cineticdaffodil 3mo ago
Also handicapped (by age or birth) individuals in nature are always squeezed into subpar territories where they then wither and sucumb