Functionally Extinct Species in Captivity

J

JVM

Well-Known Member
10+ year member
Should a species that is functionally extinct be kept in captivity?

A similar but different question: if a species could be kept alive by cloning, but not effectively bred, could that be kept in captivity?

Would either of these situations perform a strong educational message by showing visitors what can happen to a decimated species, or would they just eat time and money that could go to a critically endangered species that could be in the wild?
 
It's an interesting subject. Many zoos do hold animals that don't have conservation value and/or can't be bred for whatever reason. Mixed-subspecies tigers, certain color mutations, and so on.

At this time, I think having a situation like you describe might be a pretty bad idea if done on a large scale. Cloning is a pretty expensive procedure. If some group was doing research on extinct animals and cloned some for the purpose of research, rather than conservation, I wouldn't oppose holding the animals in zoos. But I wouldn't be a big fan of cloning animals back for the sole purpose of display in an educational facility. The insane amounts of money required would be better served to help out currently endangered and threatened species. In the future, if we get to a point where cloning can be done cheaply and easily, eh, I wouldn't mind seeing a few animals cloned for zoos.
 
JVM said:
Should a species that is functionally extinct be kept in captivity?


Would either of these situations perform a strong educational message by showing visitors what can happen to a decimated species, or would they just eat time and money that could go to a critically endangered species that could be in the wild?
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I am assuming that you are aware that species that were either functionally or actually extinct in the wild have been saved by zoos and reintroduced, e.g. Californian condor, European bison, and that their managed presence in captivity was rather more than a mere educational message and an excellent use of limited resources.
 
But those species were extinct in the wild, which is a very different thing to functionally extinct.
If you have five sterile individuals of a species still alive the species isn't extinct, but it isn't going to recover.

I don't see any point to cloning a individual if you can't get a mate for it. I don't see a point bringing back a species that can't then go on to support itself
 
How do you know? There have been many species declared extinct and then rediscovered afterwards.
When Lonesome George was discovered on Pinta/Abingdon he was taken into captivity in the hope that a female could be found, either on the island or in a zoo - what else could they do? It could have worked, so could Plan B (which was to breed hybrids with females of a related subspecies), unfortunately neither plan did work and so the subspecies became functionally extinct until the inevitable happened and George died.
At the same time the last dozen tortoises were removed from Espanola/Hood and it was found that only one of them was a male, so the outlook seemed gloomy. But in this case two further males were found in zoos and repatriated to the Galapagos and after a very successful breeding program and the extermination of introduced goats, tortoises were reintroduced to their native island.
Both stories matter. Lonesome George became an important symbol of hopelessness and the hoodensis story shows that apparently hopeless causes are not necessarily so. But the point is that when the extinction of a taxon becomes probable, rather than merely possible, action must be taken before it's too late - but you can't tell whether this action is too late or just in time until after you've taken it.

Alan
 
gentle lemur said:
How do you know? There have been many species declared extinct and then rediscovered afterwards.
When Lonesome George was discovered on Pinta/Abingdon he was taken into captivity in the hope that a female could be found, either on the island or in a zoo - what else could they do? It could have worked, so could Plan B (which was to breed hybrids with females of a related subspecies), unfortunately neither plan did work and so the subspecies became functionally extinct until the inevitable happened and George died.
At the same time the last dozen tortoises were removed from Espanola/Hood and it was found that only one of them was a male, so the outlook seemed gloomy. But in this case two further males were found in zoos and repatriated to the Galapagos and after a very successful breeding program and the extermination of introduced goats, tortoises were reintroduced to their native island.
Both stories matter. Lonesome George became an important symbol of hopelessness and the hoodensis story shows that apparently hopeless causes are not necessarily so. But the point is that when the extinction of a taxon becomes probable, rather than merely possible, action must be taken before it's too late - but you can't tell whether this action is too late or just in time until after you've taken it.

Alan
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And even Chelonoidis nigra abingdonii might not be extinct as first generation hybrids of this subspecies were found on Isabella island in 2013.
 
DDcorvus said:
And even Chelonoidis nigra abingdonii might not be extinct as first generation hybrids of this subspecies were found on Isabella island in 2013.
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I heard about this. Was it because some Pinta Tortoises had been moved there artificially e.g. by sailors/ships in the past? And what is being done now?
 
What I read is indeed that the island was used by sailors to store/dump things so it included tortoises. I believe they are now doing further testing to see if they can locate a pure animal. Taking into account the number of hybrids it might be even just one pure abingdonii.
 
DDcorvus said:
I believe they are now doing further testing to see if they can locate a pure animal. Taking into account the number of hybrids it might be even just one pure abingdonii.
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So they could come up with a 'Lonesome Fred' and the story repeat itself.:rolleyes:

I wonder if there is anything they can do with the hybrids, though if they are(presumably) all genetically 50/50 hybrids, then I'm not sure if its possible to increase the % of abingdonii by breeding further generations.
 
Pertinax said:
So they could come up with a 'Lonesome Fred' and the story repeat itself.:rolleyes:

I wonder if there is anything they can do with the hybrids, though if they are(presumably) all genetically 50/50 hybrids, then I'm not sure if its possible to increase the % of abingdonii by breeding further generations.
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If there is a Lonesome Fred (or Lonesome Georgina) they could back-cross the hybrids to him/her. But it would be very long term procedure :)

Alan
 
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gentle lemur said:
If there is a Lonesome Fred (or Lonesome Georgina) they could back-cross the hybrids to him/her. But it would be very long term procedure :)
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Yes. I meant if there wasn't a Lonesome Fred, i.e. 50/50 hybrids only. They couldn't increase the % of abingdoni in them, could they?
 
Pertinax said:
Yes. I meant if there wasn't a Lonesome Fred, i.e. 50/50 hybrids only. They couldn't increase the % of abingdoni in them, could they?
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Yes, all the F1 crosses would have 50% of the genes of each (sub)species. But if these animals were mated together the average for all the F2 individuals would still be 50:50, but there would be individual differences and in theory if enough genetic markers for the different races were known and if there were enough animals tested, I think it would be possible to select breeders with higher proportions of the characteristic genes for either race. But it would be a long and expensive process.

Alan
 
gentle lemur said:
I think it would be possible to select breeders with higher proportions of the characteristic genes for either race. But it would be a long and expensive process.

Alan
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The time factor might be insurmountable, especially with slow growers like Tortoises.
 
Pertinax said:
The time factor might be insurmountable, especially with slow growers like Tortoises.
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Patience-yoda.jpg
 
Giant Tortoises are prolific breeders if cared for correctly and will start breeding at 20 years. It will be possible to breed from hybrids and breed back to animals that are mostly abingdoni. Historically there was natural movement between islands so there will have been gene exchange so perhaps the concept of pure races on the different islands is likely to be flawed.
 
Carl Jones said:
It will be possible to breed from hybrids and breed back to animals that are mostly abingdoni. Historically there was natural movement between islands so there will have been gene exchange so perhaps the concept of pure races on the different islands is likely to be flawed.
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Does that mean that some of the hybrids are more abingdoni than others? If not, how will they increase the % of abingdoni from straight 50/50 hybrids?
 
Although they may be 50/50 hybrids, since they are taxonomically very close the parent taxa will share much of the same genetic information. Provided you have several animals you can choose for animals showing most abingdoni alleles and physical characters and selectively breed from those. Over several generation you can get back to an animal very close to the original. Also by putting the animals back on Pinta you can get natural selection to play its part as well. The aim must be to produce an animal that fulfils its ecological role as well as try and restore a lost taxonomic unit.
 
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