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Comment by ggm | Hacker News Reader

Bison could probably do the job, or moose/elk.

I'd love to see a mammoth but I think it's specious reasoning they'd be functionally important in tractable time. Building up a herd in an animal with slow gestation takes decades

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Bison and Moose clearly can't graze on developed pine/fir trees which is why the subarctic has been reforesting for 10,000 years and there's basically no subarctic steppe/grassland [1] left (after the mammoths died).

[1] https://en.wikipedia.org/wiki/Mammoth_steppe

> Building up a herd in an animal with slow gestation takes decades

We can clone them in numbers, no need to wait for the nature.

What about genetic diversity? Is there enough quality DNA to establish a hardy herd?

There isn't a hard threshold of genetic diversity you need to cross to build a successful population. It's entirely possible to succeed from bottlenecks of as few as two individuals. This has been demonstrated several times with invasive species that went on to produce tens of thousands of descendants. The feral pigs of the gulf coast and Caribbean are a good example as many of their original populations were in the double or single digits.

There's no true "minimum viable population size" as far as we know, just a continuum of increasing extinction risk as the effective population size decreases.

Are those fair comparable scenarios, though? Usually successful invasive species have some 1-up on the local fauna and can thrive. Can the same be said of the newly manufactured mammoths?

> There's no true "minimum viable population size" as far as we know

For most vertebrates, it’s as low as 2. For some species, it could be 1. Definitely more than 0.

Note that many animal species have the ability to store millions of sperm or fertilized eggs from other individuals for many years.

Such a behaviour might be a way to increase genetic diversity while populations are tiny.

Note that tiny populations can occur frequently when the environment has millions of barriers between tiny populations - eg. a water dwelling creature living in millions of tiny pools and unable to pass from one pool to the next until there is a major flood, which might only be once per thousand years.

Genetic diversity is overrated when you talk about stock animal survival. Typically it's only a problem if you can't breed enough to cull unhealthy animals. It just means that your infant mortality rate is a little higher, which can be offset by supplemented nutrition.

As the population grows larger you will see an increase in diversity due to the quirks of sexual reproduction. Also, we can just keep creating new lines of individuals and mixing them into the herd. A single bull would be able to mate with a ton of cows giving you maximum bang for your DNA buck.

The hardest part would be creating a healthy animal in the first place. Once you can do that, the rest is almost trivial in comparison. After that you can even do in-vitro testing of zygotes to select healthy stock. Especially considering how valuable they would be.

Ethically maintinaing a herd of host mother elephants, raising that many mammoth babies, the success rates for implantation, its not going to be a fast process.

"Mother" nature has one timetable which can't be altered. An elephant pregnancy lasts 18-22 months. And, a herd (assuming its Matriachal like elephants) will need to establish a dominance, and a matriarch. That will be a decade or more down the line: You can't lead a herd as a teenager.

An elephant typically gives birth every 4-5 years. So, you need multiple cycles to establish a family. This process probably needs a lot of sisters and aunties to work, they're complex social societies.

(shared a house with a Botswanian wildlife ranger decades ago, He said nothing about African herd animals is simple)

Thanks for the perspective. It's a refreshing difference from the HN refrain of "everything is an interface, and we can bend it to our will". The natural world will come for us all sooner or later.

They will need elephants as surrogate mothers.

Might be helpful to have those big wide feet?

I don't think I understand their impact on the landscape. The methane risks in the melting steppes might be something which is affected by how large animals behave in the landscape, and sure their feet would play to that. Cattle and horses are notably destructive to landscape by their feet. Sheep and Goats I think its over grazing mostly, but all of them can cause massive erosion gullies, I think thats likely to be an issue anywhere.

Elephants don’t have hooves.

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