4 ms·

I’ve read somewhere that Kiwis are in the running for being one of the closest genetic descendants / relatives of the T. rex and if they ever get off New Zealan

I’ve read somewhere that Kiwis are in the running for being one of the closest genetic descendants / relatives of the T. rex and if they ever get off New Zealand and are relieved of the island dwarfism pressure…

2muchcoffeeman 1y ago
Can’t a billionaire buy a huge island, build a sanctuary, and relieve some kiwis of this pressure? Kids a million years from now will still want to see T-Rexs
- ben_w 1y ago
  Larger than New Zealand? The two main parts of the country are the 12th and 14th largest islands on the planet: https://en.wikipedia.org/wiki/List_of_islands_by_area https://en.wikipedia.org/wiki/List_of_islands_by_area
  - b112 1y ago
    You need a really big island, like North America.
    - mort96 1y ago
      Is NA really an island? I always thought it was a peninsula on the coast of Central America
      - layer8 1y ago
        In that case, it's almost more plausible to count the Panama canal as a strait.
      - nkrisc 1y ago
        By that measure there's only one continent with a very, very large saltwater lake.
        IAmBroom 1y ago
        Nonsense. There's four. One is icy AF, and another contains 95% of the world's deadly organisms.
  - bregma 1y ago
    I heard a wealthy man is looking to buy Greenland. Maybe it's for the birds?
  - nandomrumber 1y ago
    New Zealand's total land area is about the same as Colorado or Oregon, and the five extant species of Kiwi inhabits a fraction of that.
arp242 1y ago
New Zealand is nowhere near small enough for island dwarfism.
- nandomrumber 1y ago
  Maybe, although a more correct term is insular dwarfism, whereby populations are supposedly subject if they’re isolated in anyway. Definitely not my area of expertise though, purely a fun speculation.
  - im3w1l 1y ago
    Not super knowledgeable either, but I'm thinking that it's simply because it's fairly easy for animals to change size. Like imagine a size constant in your code and you can just update it and everything magically works. So when you have two populations that get cut off with slighly different environments and selection pressures their sizes are likely to diverge.
    - thaumasiotes 1y ago
      > I'm thinking that it's simply because it's fairly easy for animals to change size. Like imagine a size constant in your code and you can just update it and everything magically works. No, the opposite is the case. You can just scale an animal up. But it won't work well; the larger size requires different support structures than the normal size does. Hence, giant humans tend to be in poor health, with circulatory and other problems. The reason island populations show size changes is that the tiny environment leaves environmental niches open, and animals of the wrong size can radiate into those empty niches without facing competition from animals that are already filling them more effectively. Island dwarfism is common, and so is island gigantism. Note that New Zealand obviously is small enough for island dwarfism, since it was small enough for island gigantism. The size seems less relevant than the fact that it was isolated by deep ocean.
chris1993 1y ago
Moa seemed to contradict this
cenamus 1y ago
What about island gigantism? With no large scale predator, you can just grow bigger
- dredmorbius 1y ago
  Island birds may become flightless, which lifts constraint on maximum mass. Though that occurs in other contexts as well: Antarctica (hardly small) with penguins, Africa (dittos) and ostriches, Australia (again) with emus, and South America (again) with the rhea. There are also flightless island birds, such as the Guam Rail, Henderson crake, Inaccessible Island rail, and across multiple islands, the cassowary.

2muchcoffeeman 1y ago

Can’t a billionaire buy a huge island, build a sanctuary, and relieve some kiwis of this pressure? Kids a million years from now will still want to see T-Rexs

ben_w 1y ago
Larger than New Zealand? The two main parts of the country are the 12th and 14th largest islands on the planet: https://en.wikipedia.org/wiki/List_of_islands_by_area https://en.wikipedia.org/wiki/List_of_islands_by_area
- b112 1y ago
  You need a really big island, like North America.
  - mort96 1y ago
    Is NA really an island? I always thought it was a peninsula on the coast of Central America
    - layer8 1y ago
      In that case, it's almost more plausible to count the Panama canal as a strait.
    - nkrisc 1y ago
      By that measure there's only one continent with a very, very large saltwater lake.
      - IAmBroom 1y ago
        Nonsense. There's four. One is icy AF, and another contains 95% of the world's deadly organisms.
- bregma 1y ago
  I heard a wealthy man is looking to buy Greenland. Maybe it's for the birds?
- nandomrumber 1y ago
  New Zealand's total land area is about the same as Colorado or Oregon, and the five extant species of Kiwi inhabits a fraction of that.

arp242 1y ago

New Zealand is nowhere near small enough for island dwarfism.

nandomrumber 1y ago
Maybe, although a more correct term is insular dwarfism, whereby populations are supposedly subject if they’re isolated in anyway. Definitely not my area of expertise though, purely a fun speculation.
- im3w1l 1y ago
  Not super knowledgeable either, but I'm thinking that it's simply because it's fairly easy for animals to change size. Like imagine a size constant in your code and you can just update it and everything magically works. So when you have two populations that get cut off with slighly different environments and selection pressures their sizes are likely to diverge.
  - thaumasiotes 1y ago
    > I'm thinking that it's simply because it's fairly easy for animals to change size. Like imagine a size constant in your code and you can just update it and everything magically works. No, the opposite is the case. You can just scale an animal up. But it won't work well; the larger size requires different support structures than the normal size does. Hence, giant humans tend to be in poor health, with circulatory and other problems. The reason island populations show size changes is that the tiny environment leaves environmental niches open, and animals of the wrong size can radiate into those empty niches without facing competition from animals that are already filling them more effectively. Island dwarfism is common, and so is island gigantism. Note that New Zealand obviously is small enough for island dwarfism, since it was small enough for island gigantism. The size seems less relevant than the fact that it was isolated by deep ocean.

chris1993 1y ago

Moa seemed to contradict this

cenamus 1y ago

What about island gigantism? With no large scale predator, you can just grow bigger

dredmorbius 1y ago
Island birds may become flightless, which lifts constraint on maximum mass. Though that occurs in other contexts as well: Antarctica (hardly small) with penguins, Africa (dittos) and ostriches, Australia (again) with emus, and South America (again) with the rhea. There are also flightless island birds, such as the Guam Rail, Henderson crake, Inaccessible Island rail, and across multiple islands, the cassowary.