Where did this figure of 80 individuals come from? Last time I studied conservation biology the figure for a genetically self-sustaining population was 250 breeding pairs.
Hix
Interview with David Hancocks about the future of zoos
- Thread starter DavidBrown
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Where did this figure of 80 individuals come from? Last time I studied conservation biology the figure for a genetically self-sustaining population was 250 breeding pairs.
Hix
Hallo Hix
I'm sorry I can't remember where I got the figure of 80 from. Many years ago, I attended a course on ecology and conservation at London Zoo, but I have also read many books and websites, watched TV programmes and visited zoos and museums and it could have come from any of these, but I think it has something to do with ISIS. I remember a statement that if zoos devoted half their space to endangered species they could save a few thousand species of vertebrates and I think the number of 80 distantly-related individuals may be linked with this. It makes a lot of sense for many larger species, which may be why it made such a big impression on me. I accept that it wouldn't work for species that need large populations in order to breed. While the passenger pigeon was kept in various zoos, it is unlikely that it could have been bred successfully in the late C19th and early C20th.
If I find confirmation for this figure, I'll try and let other Zoochatters know.
I'm sorry I can't remember where I got the figure of 80 from. Many years ago, I attended a course on ecology and conservation at London Zoo, but I have also read many books and websites, watched TV programmes and visited zoos and museums and it could have come from any of these, but I think it has something to do with ISIS. I remember a statement that if zoos devoted half their space to endangered species they could save a few thousand species of vertebrates and I think the number of 80 distantly-related individuals may be linked with this. It makes a lot of sense for many larger species, which may be why it made such a big impression on me. I accept that it wouldn't work for species that need large populations in order to breed. While the passenger pigeon was kept in various zoos, it is unlikely that it could have been bred successfully in the late C19th and early C20th.
If I find confirmation for this figure, I'll try and let other Zoochatters know.
This is a really great thread!
I believe the SSP standards for many animals in the US (AZA) is to maintain a target population of 80. I am pretty sure I read this in some report by the Felid TAG about small cats. However, as mentioned above, I believe the IUCN Conservation Specialist Breeding Group recommends 250 as a minimum viable population.
As for elephant conservation, yes several zoos contribute to the Foley's project in Tanzania (I had the pleasure of hearing Charles Foley speak at our zoo last year). I know my small zoo (Reid Park in Tucson) gives him an annual contribution of ten thousand dollars. And yes, our new elephant exhibit that opens in a couple weeks is called Expedition Tanzania because we are tying in the educational graphics directly to the Foley's project.
As for zoos diversifying, the ideal situation is what you have in my city of Tucson. We have two zoos - one devoted exclusively to local sonoran desert wildlife (from black bears to gila monsters) and one devoted to exotic animals (from giraffes to dwarf caiman). There are several "twin cities" in the US that each have a zoo, but sadly most of these choose to duplicate animals instead of differentiating. They could do so much more if they chose to distinguish themselves from each other like we do in Tucson. Just think of how similar (species wise) these neighboring institutions are: Lincoln Park and Brookfield (Chicago), Wildlife World and Phoenix, Dallas and Fort Worth, Minneapolis (Minnesota Zoo) and St Paul, San Francisco and Oakland. The only twin cities I can think of where the zoos are quite a bit different (though still some overlap) are Seattle and Tacoma.
As for Joe Public not being interested in small or unpopular animals, I was amazed at the crowds (and their interest) when I visited the insect house at London Zoo. Also people LOVE seeing the small animals that we docents take out for people to touch at my zoo (hedgehog, hairy armadillo, ball python, etc). Sure you need the popular animals, but I think the so-called unpopular animals are not as unpopular as some zoo staff think.
I believe the SSP standards for many animals in the US (AZA) is to maintain a target population of 80. I am pretty sure I read this in some report by the Felid TAG about small cats. However, as mentioned above, I believe the IUCN Conservation Specialist Breeding Group recommends 250 as a minimum viable population.
As for elephant conservation, yes several zoos contribute to the Foley's project in Tanzania (I had the pleasure of hearing Charles Foley speak at our zoo last year). I know my small zoo (Reid Park in Tucson) gives him an annual contribution of ten thousand dollars. And yes, our new elephant exhibit that opens in a couple weeks is called Expedition Tanzania because we are tying in the educational graphics directly to the Foley's project.
As for zoos diversifying, the ideal situation is what you have in my city of Tucson. We have two zoos - one devoted exclusively to local sonoran desert wildlife (from black bears to gila monsters) and one devoted to exotic animals (from giraffes to dwarf caiman). There are several "twin cities" in the US that each have a zoo, but sadly most of these choose to duplicate animals instead of differentiating. They could do so much more if they chose to distinguish themselves from each other like we do in Tucson. Just think of how similar (species wise) these neighboring institutions are: Lincoln Park and Brookfield (Chicago), Wildlife World and Phoenix, Dallas and Fort Worth, Minneapolis (Minnesota Zoo) and St Paul, San Francisco and Oakland. The only twin cities I can think of where the zoos are quite a bit different (though still some overlap) are Seattle and Tacoma.
As for Joe Public not being interested in small or unpopular animals, I was amazed at the crowds (and their interest) when I visited the insect house at London Zoo. Also people LOVE seeing the small animals that we docents take out for people to touch at my zoo (hedgehog, hairy armadillo, ball python, etc). Sure you need the popular animals, but I think the so-called unpopular animals are not as unpopular as some zoo staff think.
Interview with David Hancocks
Re Passenger Pigeons. The Early of Derby bred so many of these in the early 1800s that he was letting them out; somewhere I have a note of how many were sold at the collection dispersal sale after his death, enough to have kept the species going indefinitely.
Re Passenger Pigeons. The Early of Derby bred so many of these in the early 1800s that he was letting them out; somewhere I have a note of how many were sold at the collection dispersal sale after his death, enough to have kept the species going indefinitely.
Thanks, Arizona Docent. I was pretty sure I hadn't made up the figure. I suppose that the minimum figure may depend on the social structure of a species, as well as genetic diversity. As some species live in very large groups, a total of 80 may only mean a few zoos keeping that species. That doesn't get around the fact that some species are over-represented. Perhaps zoos need to agree a maximum figure.
I'm also pleased that there are several people interested in non-elite species. There were quite a few people looking at the corals at London Zoo on Sunday and the Butterfly Paradise is often packed. One of my best experiences last year was when an animal show occurred at the library where I work. I only found out when the presenters were about to leave, but I asked which animals they'd shown. When I asked which armadillos they showed, the reply was 'three-banded armadillos.' I tried looking for three-banded armadillos at Prague Zoo in 2009, but to no avail. When I asked one of the crew to show me the armadillo, he opened a crate. I not only touched an armadillo - I held one in my hands. As Arizona Docent says, some customers prefer personal contact with smaller animals rather than seeing larger animals from a distance.
Thanks FBBird for your information about the Earl of Derby. I had read the story that colonies stopped breeding when the numbers dropped dramatically. It's a pity there wasn't someone similar in the late C19th who could have bred the pigeons and saved them from extinction.
I'm also pleased that there are several people interested in non-elite species. There were quite a few people looking at the corals at London Zoo on Sunday and the Butterfly Paradise is often packed. One of my best experiences last year was when an animal show occurred at the library where I work. I only found out when the presenters were about to leave, but I asked which animals they'd shown. When I asked which armadillos they showed, the reply was 'three-banded armadillos.' I tried looking for three-banded armadillos at Prague Zoo in 2009, but to no avail. When I asked one of the crew to show me the armadillo, he opened a crate. I not only touched an armadillo - I held one in my hands. As Arizona Docent says, some customers prefer personal contact with smaller animals rather than seeing larger animals from a distance.
Thanks FBBird for your information about the Earl of Derby. I had read the story that colonies stopped breeding when the numbers dropped dramatically. It's a pity there wasn't someone similar in the late C19th who could have bred the pigeons and saved them from extinction.
Interview with David Hancocks...
The Knowsley Passenger Pigeons are one of aviculture's lost opportunities. Dodos were exhibited in London, but nobody thought of breeding them. The really scary story is the Nene Goose. The Earl of Derby bred them, London Zoo bred them, but the stock was allowed to dwindle and the last survivor died in France in the Second World War. Nobody realised how rare they were becoming in the wild; fortunately Peter Scott & the Wildfowl Trust stepped in, and there are now plenty about. They so nearly went the way of the Passenger Pigeon. The need of the latter to breed in vast colonies was probably specific to the wild setting; Lord Derby would not have had more than a dozen or so birds in an aviary. With a little foresight we could have had these birds in captive culture today. On the other hand, we could have lost the Nene as well. Quaggas should have been easy to establish if anyone had tried.
The Knowsley Passenger Pigeons are one of aviculture's lost opportunities. Dodos were exhibited in London, but nobody thought of breeding them. The really scary story is the Nene Goose. The Earl of Derby bred them, London Zoo bred them, but the stock was allowed to dwindle and the last survivor died in France in the Second World War. Nobody realised how rare they were becoming in the wild; fortunately Peter Scott & the Wildfowl Trust stepped in, and there are now plenty about. They so nearly went the way of the Passenger Pigeon. The need of the latter to breed in vast colonies was probably specific to the wild setting; Lord Derby would not have had more than a dozen or so birds in an aviary. With a little foresight we could have had these birds in captive culture today. On the other hand, we could have lost the Nene as well. Quaggas should have been easy to establish if anyone had tried.
Thanks FBBird
I thought you might be interested in an article about Carl Jones (DURRELL?S CARL JONES NOMINATED FOR THE 2012 INDIANAPOLIS PRIZE) being nominated for the Indianapolis Prize. He managed to save 5 species of bird from extinction, including the Mauritius kestrel, pink pigeon and echo parakeet. In each case, there were fewer than 10 individuals (far fewer than the 80 individuals or 250 pairs discussed earlier in this thread). I remember reading Gerald Durrell's Army, where Carl Jones defied bird conservation organisations that said that the species were doomed to extinction and weren't worth saving. He is a prime example of true conservation, someone who has saved several species from extinction.
I thought you might be interested in an article about Carl Jones (DURRELL?S CARL JONES NOMINATED FOR THE 2012 INDIANAPOLIS PRIZE) being nominated for the Indianapolis Prize. He managed to save 5 species of bird from extinction, including the Mauritius kestrel, pink pigeon and echo parakeet. In each case, there were fewer than 10 individuals (far fewer than the 80 individuals or 250 pairs discussed earlier in this thread). I remember reading Gerald Durrell's Army, where Carl Jones defied bird conservation organisations that said that the species were doomed to extinction and weren't worth saving. He is a prime example of true conservation, someone who has saved several species from extinction.
The 1851 Catalogue for the sale of the Knowsley Menagerie lists 70 passenger pigeons!
Interview with...
Thank you for that; marvellous bloke, Carl Jones. The ultimate 'comeback from a small gene pool' must be the Laysan Teal, supposed to have been down to the ultimate population low of one female [with enough sperm on board to fertilise a clutch of eggs]. It is possible that island species are naturally resilient [eg to the effects of inbreeding], but it seems common sense that to hold a large gene pool must give the best chance for long-term genetic viability.
Thank you for that; marvellous bloke, Carl Jones. The ultimate 'comeback from a small gene pool' must be the Laysan Teal, supposed to have been down to the ultimate population low of one female [with enough sperm on board to fertilise a clutch of eggs]. It is possible that island species are naturally resilient [eg to the effects of inbreeding], but it seems common sense that to hold a large gene pool must give the best chance for long-term genetic viability.
all Chatham Island black robins alive today can also trace their origin back to a single female. Insular species generally do seem to be resistant to inbreeding effects, probably because they are descended from small founder populations to begin with and any deleterious genes were weeded out a long time ago.
While species with very small populations may show no visible signs of inbreeding, it is still present in subsequent generations, as is genetic drift. The result is a loss of genetic diversity. This can be overcome in species which reproduce rapidly and in large numbers (like mice) because there is a greater probability of gene mutations occurring.
One of the side-effects of a lack of genetic diversity means that the entire population is susceptible to disease, there is no natural (=genetic) immunity. It also limits their ability to adapt to change in their environment. While the bird species listed above might survive for many generations to come, in the future they may find themselves in the same situation as the cheetah is in today (the cheetah is believed to have survived a genetic bottleneck - only 15 animals about 10,000 years ago - and today exhibit virtually no genetic diversity and little disease resistance).
Having said that, birds can reproduce faster than cheetahs and the populations of the species listed above have been managed (by people) to maintain as much diversity as possible, so they're in a better position than the cheetahs were.
Hix
One of the side-effects of a lack of genetic diversity means that the entire population is susceptible to disease, there is no natural (=genetic) immunity. It also limits their ability to adapt to change in their environment. While the bird species listed above might survive for many generations to come, in the future they may find themselves in the same situation as the cheetah is in today (the cheetah is believed to have survived a genetic bottleneck - only 15 animals about 10,000 years ago - and today exhibit virtually no genetic diversity and little disease resistance).
Having said that, birds can reproduce faster than cheetahs and the populations of the species listed above have been managed (by people) to maintain as much diversity as possible, so they're in a better position than the cheetahs were.
Hix
DejaVuKatz
Active Member
Well here is the funny thing, the elite animals aren't picked out by children, but by the adults. I remember when i was little my favorite animal to see was the tapir, im sure it had to do with something about the nose. Today I really love to see the clouded leopard and the babirusa over the tiger and elephants at Lowry.
I think in part it is also because of the enclosures now a days. The tiger is always pacing by the back wall and the view I see is from the bridge is a distant one since they bricked in the glass viewing area tunnel many eons ago. The clouded leopards are normally never active, but the view is through harp string wire and they often sleep on a ledge close to the wire. In general tho they are a little difficult to see, but when visible its normally close, or at least much closer then the tiger. The babirusa are often very close and active. I also just like how their tusks look. For some reason as active as the elephants are they just boar me, I don't mind sitting and watching them, but I am no where near as emotionally attached to them and often I just want to move on to find the okapi despite the luxurious elephant exhibit.
I think that also that they should look to different representation subspecies of the elite fauna that do need breeding programs. For example south china tigers are the rarest and right now Save China's tigers are trying to breed and rewild these the few tigers found in china's zoos. Instead of white rhino there could be java rhino. Though, talking the government into allowing anyone to remove a few from the island hasn't gone well. That was also one of the reasons the Vietnam subspecies had gone extinct, they would not allow for their removal of theirs to Java and Java would not allow a few of theirs to be sent to Vietnam. A good example of this elite trade off has been the Sumatran Rhinos. They have become very popular over at Cincinnati Zoo from my understanding. Also, here in America there are no Asian Lions, but plenty of African. Also how about a switch to Borneo elephant instead of African?
I wish that zoos could send excess animals out to sites that could rewild animals of a variety of species. Zoos could be the sort of "factories" to pump out animals for the wild. In many readings it always sounds like this is what they are trying to achieve, yet I never hear about animals being sent back out. If there was a rotation of animals brought in for breeding for a couple years then traded back for another wild animal it would allow for more genetic diversity without having to maintain the animal for the duration of its life in captivity. With carnivores care must be taken to diminish any association with people and food. So maybe that wouldn't be the best rout for say a tiger, they would be too accustomed to people, but it would work for say a vaquita dolphin. It might even promote the tourism there if they weren't as shy and allow for fishermen to make money another way instead of casting nets that are the main threat to these dolphins.
I think in part it is also because of the enclosures now a days. The tiger is always pacing by the back wall and the view I see is from the bridge is a distant one since they bricked in the glass viewing area tunnel many eons ago. The clouded leopards are normally never active, but the view is through harp string wire and they often sleep on a ledge close to the wire. In general tho they are a little difficult to see, but when visible its normally close, or at least much closer then the tiger. The babirusa are often very close and active. I also just like how their tusks look. For some reason as active as the elephants are they just boar me, I don't mind sitting and watching them, but I am no where near as emotionally attached to them and often I just want to move on to find the okapi despite the luxurious elephant exhibit.
I think that also that they should look to different representation subspecies of the elite fauna that do need breeding programs. For example south china tigers are the rarest and right now Save China's tigers are trying to breed and rewild these the few tigers found in china's zoos. Instead of white rhino there could be java rhino. Though, talking the government into allowing anyone to remove a few from the island hasn't gone well. That was also one of the reasons the Vietnam subspecies had gone extinct, they would not allow for their removal of theirs to Java and Java would not allow a few of theirs to be sent to Vietnam. A good example of this elite trade off has been the Sumatran Rhinos. They have become very popular over at Cincinnati Zoo from my understanding. Also, here in America there are no Asian Lions, but plenty of African. Also how about a switch to Borneo elephant instead of African?
I wish that zoos could send excess animals out to sites that could rewild animals of a variety of species. Zoos could be the sort of "factories" to pump out animals for the wild. In many readings it always sounds like this is what they are trying to achieve, yet I never hear about animals being sent back out. If there was a rotation of animals brought in for breeding for a couple years then traded back for another wild animal it would allow for more genetic diversity without having to maintain the animal for the duration of its life in captivity. With carnivores care must be taken to diminish any association with people and food. So maybe that wouldn't be the best rout for say a tiger, they would be too accustomed to people, but it would work for say a vaquita dolphin. It might even promote the tourism there if they weren't as shy and allow for fishermen to make money another way instead of casting nets that are the main threat to these dolphins.
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Zooplantman
Well-Known Member
You can read David Hancock's actual paper from the Symposium on Zoolex:
Beyond the Animal: Exhibiting and Interpreting Nature by David Hancocks (download 35 KB) http://www.zoolex.org/publication/hancocks/Future_of_Zoos_Hancocks_2012.pdf
Beyond the Animal: Exhibiting and Interpreting Nature by David Hancocks (download 35 KB) http://www.zoolex.org/publication/hancocks/Future_of_Zoos_Hancocks_2012.pdf
Thanks for posting Zooplantman.
I think that he makes some good points about zoos needing to undertake honest self-reflection and criticism about their missions and how well they are meeting them.
He says that zoos should not highlight megafauna species in their promotions, which I find puzzling. He asserts that small species make the best exhibits for promoting biodiversity lessons. I wonder if there is any kind of research to back up what he says here, or if it is primarily his opinion:
"Zoos with welfare at their heart would raise new standards of
awareness of animals’ needs; would recognize the impossibility of
satisfying the needs of many traditional zoo species; would give new
attention to all the small species that do well in captivity, many of
which used to be common in zoos but through negligence have
disappeared. Zoos would then realize that smaller species can better
promote biodiversity awareness and allow more illustrative stories;
they would discover they can create and maintain more convincingly
naturalistic exhibits; and with very small life forms promote more direct
examples of interdependence and interconnectedness, and thereby
more effective ecology based stories."