# What is the least populous surviving species? **URL:** \ **Category:** Factual Questions\ **Created:** [July 26, 2017, 5:36pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183 "2017-07-26T17:36:57Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [July 26, 2017, 5:36pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/1 "2017-07-26T17:36:57Z")
What is the least populous surviving species? By “populous” I mean counting the number of individuals. By “surviving” I mean very likely to survive for the foreseeable future, so not threatened, endangered, extinct, etc. I’m most curious about animals, but plants are fine as well. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [July 26, 2017, 5:40pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/2 "2017-07-26T17:40:05Z")
So you’re asking how small a population can get before it’s considered threatened? ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [July 26, 2017, 5:47pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/3 "2017-07-26T17:47:43Z")
I can’t name you a specific species, but the concept is “[minimum viable population](https://en.wikipedia.org/wiki/Minimum_viable_population).” _“An MVP of 500 to 1,000 has often been given as an average for terrestrial vertebrates when inbreeding or genetic variability is ignored. When inbreeding effects are included, estimates of MVP for many species are in the thousands.”_ ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 26, 2017, 5:54pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/4 "2017-07-26T17:54:38Z")
There is no way to answer this definitively. Whether a species is considered to be “threatened” under the [Red List criteria of the International Union for the Conservation of Nature](http://www.iucnredlist.org/static/categories_criteria_3_1) depends on a complex combination of factors, including population size, historical decreases in population, range size, and threats. “Threatened” includes the categories of Critically Endangered, Endangered, and Vulnerable. Any species with a population of fewer than 1,000 mature individuals is automatically considered to be at least Vulnerable and hence threatened. So this would be a minimum cut off to not be considered threatened. In practice, many species with populations of fewer than 10,000 individuals will be considered threatened if they are in decline. There would be few species with populations of just over 1,000 that would not be considered threatened. It would be a chore looking them up. ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [July 26, 2017, 5:55pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/5 "2017-07-26T17:55:00Z")
Also, I’d like information about the world’s tallest dwarf. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [July 26, 2017, 6:03pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/6 "2017-07-26T18:03:11Z")
I’m asking what species that isn’t endangered (etc) has the fewest individuals. For example, from random Googling, whited-tailed deer have a population of something like 30 million and are no danger of extinction. Are there any non-threatened species with fewer individuals? I’m curious what animal (or plant) species are likely to be around for a long time, but are comparatively rare now. So species that have a limited geographic distribution, but common within that area. Or species that have a wide geographic distribution, but an extremely low-density population. **Colibri** : yeah, I know it’d be a chore, that’s why I’m asking. 😃 I’m not expecting a definitive answer, but rather “anecdotal” comments of the sort “oh, how about _X. xyz_, they’re doing well even though there’s not many of them”. I’ve found the Wikipedia page: [Least-concern species - Wikipedia](https://en.wikipedia.org/wiki/Least-concern_species) which does list candidate species for my query. But it’s more fun to get educated guesses here than reading Wikipedia pages. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [July 26, 2017, 6:09pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/7 "2017-07-26T18:09:02Z")
> [@Darren\_Garrison](#): > > I can’t name you a specific species, but the concept is “[minimum viable population](https://en.wikipedia.org/wiki/Minimum_viable_population).” > > _“An MVP of 500 to 1,000 has often been given as an average for terrestrial vertebrates when inbreeding or genetic variability is ignored. When inbreeding effects are included, estimates of MVP for many species are in the thousands.”_ Well, maybe. But then there’s the Whooping Crane, > **[Whooping crane](https://en.wikipedia.org/wiki/Whooping_crane)** > > Ardea americana Linnaeus, 1758 > The whooping crane (Grus americana) is an endangered crane species, native to North America, named for its “whooping” calls. Along with the sandhill crane (Antigone canadensis), it is one of only two crane species native to North America, and it is also the tallest North American bird species. The whooping crane's lifespan is estimated to be 22-24 years in the wild. After being pushed to the brink of extinction, due to unregulated hunting and loss of habitat, and... 15 adults in 1938. Now over 600. And the Peregrine falcon, once on the edge, now Ok. VIRGINIA NORTHERN FLYING SQUIRREL: once only 10 individuals, now 1100. There are very few Wyoming toads:[Wyoming toad - Wikipedia](https://en.wikipedia.org/wiki/Wyoming_toad) There are 115 of Hawaiian Crows. [Hawaiian crow - Wikipedia](https://en.wikipedia.org/wiki/Hawaiian_crow) Sumatran rhinoceroses-. Fewer than 100 individuals remain. Javan rhinoceros= 50. Northern white rhinoceros= 3 > **[Northern white rhinoceros](https://en.wikipedia.org/wiki/Northern_white_rhinoceros)** > > The northern white rhinoceros or northern white rhino (Ceratotherium simum cottoni) is one of two subspecies of the white rhinoceros (the other being the southern white rhinoceros). This subspecies is a grazer in grasslands and savanna woodlands. Formerly found in several countries in East and Central Africa south of the Sahara, since 19 March 2018, there are only two known rhinos of this subspecies left, named Najin and Fatu, both of which are female; barring the existence of unknown or miscl... > **[List of critically endangered mammals](https://en.wikipedia.org/wiki/List_of_critically_endangered_mammals)** > > As of January 2020, the International Union for Conservation of Nature (IUCN) listed 203 critically endangered mammalian species, including 31 which are tagged as possibly extinct. Of all evaluated mammalian species, 3.5% are listed as critically endangered. > The IUCN also lists 60 mammalian subspecies as critically endangered. > Of the subpopulations of mammals evaluated by the IUCN, 18 species subpopulations have been assessed as critically endangered. > Additionally 900 mammalian species (15% ... ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 26, 2017, 6:27pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/8 "2017-07-26T18:27:10Z")
> [@DrDeth](#): > > Well, maybe. But then there’s the Whooping Crane, > [Whooping crane - Wikipedia](https://en.wikipedia.org/wiki/Whooping_crane) > 15 adults in 1938. Now over 600. > > And the Peregrine falcon, once on the edge, now Ok. > > VIRGINIA NORTHERN FLYING SQUIRREL: once only 10 individuals, now 1100. > There are very few Wyoming toads:[Wyoming toad - Wikipedia](https://en.wikipedia.org/wiki/Wyoming_toad) > > There are 115 of Hawaiian Crows. [Hawaiian crow - Wikipedia](https://en.wikipedia.org/wiki/Hawaiian_crow) > > Sumatran rhinoceroses-. Fewer than 100 individuals remain. > Javan rhinoceros= 50. > Northern white rhinoceros= 3 > [Northern white rhinoceros - Wikipedia](https://en.wikipedia.org/wiki/Northern_white_rhinoceros) > [List of critically endangered mammals - Wikipedia](https://en.wikipedia.org/wiki/List_of_critically_endangered_mammals) I’m not sure what your point is. Those examples vary wildly, and none of them really have anything to do with MVP, which is based on statistical probabilities. Having a population below the MVP doesn’t mean a species will go extinct, just that it is likely non-viable without intensive conservation programs. The Northern White Rhino is far below its MVP, which means it almost certainly would not survive without intensive management (which it is receiving). Peregrine Falcons, even though they were reduced in the past, never hit anything close to their MVP, and have rebounded on their own after pesticides were banned. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [July 26, 2017, 6:39pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/9 "2017-07-26T18:39:31Z")
> [@Pleonast](#): > > I’m curious what animal (or plant) species are likely to be around for a long time, but are comparatively rare now. Considering climate change, habit destruction, trophy hunting, poaching, etc., I’m guessing a figure damn close to “none.” ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [July 26, 2017, 6:52pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/10 "2017-07-26T18:52:46Z")
George … The last Pinta tortoise (from the Galapagos Islands) … functionally extinct as he is the only remaining Pinta tortoise alive … ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 26, 2017, 6:53pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/11 "2017-07-26T18:53:16Z")
> [@Darren\_Garrison](#): > > Considering climate change, habit destruction, trophy hunting, poaching, etc., I’m guessing a figure damn close to “none.” With the exception of human commensals like rats and pigeons, of course.😉 With these exceptions, it is unfortunately true that probably a majority of vertebrate species are declining in population. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 26, 2017, 6:55pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/12 "2017-07-26T18:55:43Z")
> [@watchwolf49](#): > > George … > > The last Pinta tortoise (from the Galapagos Islands) … functionally extinct as he is the only remaining Pinta tortoise alive … I hate to break it to you, but [Lonesome George](https://en.wikipedia.org/wiki/Lonesome_George) died over five years ago. ☹ ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [July 26, 2017, 6:59pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/13 "2017-07-26T18:59:32Z")
> [@Colibri](#): > > I hate to break it to you, but [Lonesome George](https://en.wikipedia.org/wiki/Lonesome_George) died over five years ago. ☹ NOOOOOOOOOOOOOoooooooooooooo… ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 26, 2017, 7:02pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/14 "2017-07-26T19:02:48Z")
Was genetic information from George preserved? Is there another tortoise species that’s closely-enough related for its eggs to be used as a surrogate? Is the genetic information in a male, in that species, sufficient to also produce a female? In other words, is it possible to bring the Pinta tortoise back from extinction? ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [July 26, 2017, 7:03pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/15 "2017-07-26T19:03:07Z")
> [@Colibri](#): > > With the exception of human commensals like rats and pigeons, of course. But Pleonast said species that are comparatively rare now, and most human commensals ain’t. But species with limited numbers and/or restricted habitats, like lions and tigers and bears? Screwed. ---
**Author:** ![Gymnopithys](https://avatars.discourse-cdn.com/v4/letter/g/fbc32d/32.png) [@Gymnopithys](https://boards.straightdope.com/u/Gymnopithys)\ **Post date:** [July 26, 2017, 7:12pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/16 "2017-07-26T19:12:59Z")
Perhaps some cave inhabiting species, like the Protea in Slovenia or some fish species in Mexico. I’ve seen recently a documentary about a species of fish living in an aquifer in the U.S., with a population of less than a hundred individuals. Im sure Colibri can tell more about it. I just found out: “Stygofauna” in Wikipedia. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 26, 2017, 7:18pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/17 "2017-07-26T19:18:34Z")
> [@Chronos](#): > > Was genetic information from George preserved? Is there another tortoise species that’s closely-enough related for its eggs to be used as a surrogate? Is the genetic information in a male, in that species, sufficient to also produce a female? In other words, is it possible to bring the Pinta tortoise back from extinction? See the link in my post. There is more information [here.](https://www.galapagos.org/newsroom/lonesome-georges-genetic-legacy-survives/) Turtles with significant Pinta ancestry have been found on nearby Wolf island and could be used to breed back the species. Sex determination in turtles usually depends on the temperature the eggs are incubated at rather than sex chromosomes, so eggs can produce either sex. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [July 26, 2017, 9:10pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/18 "2017-07-26T21:10:21Z")
> [@Colibri](#): > > I’m not sure what your point is. Those examples vary wildly, and none of them really have anything to do with MVP, which is based on statistical probabilities. Having a population below the MVP doesn’t mean a species will go extinct, just that it is likely non-viable without intensive conservation programs. The Northern White Rhino is far below its MVP, which means it almost certainly would not survive without intensive management (which it is receiving). Peregrine Falcons, even though they were reduced in the past, never hit anything close to their MVP, and have rebounded on their own after pesticides were banned. Well, the first half was pointing out that some species went well below “500 to 1,000” individuals and survived. The next half was pointing out some species on the edge, which I did not make clear. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 26, 2017, 9:18pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/19 "2017-07-26T21:18:21Z")
> [@DrDeth](#): > > Well, the first half was pointing out that some species went well below “500 to 1,000” individuals and survived. > > The next half was pointing out some species on the edge, which I did not make clear. As I said, that’s not relevant to MVP. From the link in post 3: > [@](#): > > Minimum viable population is usually estimated as the population size necessary to ensure between 90 and 95 percent probability of survival between 100 and 1,000 years into the future. And: > [@](#): > > MVP does not take human intervention into account. Thus, it is useful for conservation managers and environmentalists; a population may be increased above the MVP using a captive breeding program, or by bringing other members of the species in from other reserves. Therefore, the fact that a species currently has a population lower than its MVP but still survives _at present_ is irrelevant. The MVP is a statistical model that predicts the survival of such populations in the wild in the future. The MVP is a tool for conservation planning. It is not a deterministic prediction of which species will survive or not. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 26, 2017, 10:14pm UTC](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183/20 "2017-07-26T22:14:08Z")
> [@](#): > > Quoth **Colibri** : > > Sex determination in turtles usually depends on the temperature the eggs are incubated at rather than sex chromosomes, so eggs can produce either sex. I thought it might be something like that. Alternately, even in species where sex is genetic, such things might still be possible: In mammals, for instance, one could take the chromosomes for a male, duplicate the X and throw out the Y, and get the chromosomes for a female. On the other hand, you couldn’t do this with a male bird, because in birds, it’s the females who are heterozygous and the males homozygous. [Next page](https://boards.straightdope.com/t/what-is-the-least-populous-surviving-species/792183.md?page=2)