When you see news about the extinction of animals on TV or online, many people instinctively feel that they want to protect them. In fact, in the field of nature maintenance, various efforts are being made to prevent the extinction of animals.
However, it is not possible to revive extinct species with human technology or to protect and breed endangered animals.Is it really the “right” act?It was the book of American journalist MR O’Connor who cut into such a question head-on.“Animals that cannot be extinct”is.
This bookteeth,“Is it’good’to prevent extinction?”It is a unique non-fiction that focuses on the ethical issue of, and is often talked about on Twitter. In this article,This bookExcerpted and edited from a part of the contents ofProbability of returning to “wild”Reveal. (Composition / Hayane Nemoto)
Zoos and aquariums save animals from endangered species
There are pros and cons to captive breeding as a means of conservation. However, I cannot deny the feeling that it is now.Zoos and aquariums have been the caretakers of endangered species for many years.
The California condor, whooping crane, black-footed ferret, Arabian oryx, and crocodile lizard all escaped the imminent danger of extinction because biologists brought them into a well-managed environment. In such an environment, biologists were able to manage these populations and genetic material.
Since the 1973 Act on Conservation of Species
“more and more people want to do more than manage the animals they collect as zoo directors,” said Chris Wemmer, an emeritus researcher at the Smithsonian National Zoo. “The belief that humans can save wild animals was strong.”
* 1973 Species Conservation Law: A law passed in the United States that risks extinction of animals and plants and the risk of destroying “aesthetic value, ecological value, educational value, enjoyable value, and scientific value of animals and plants”. Admitted to exist
But most of the time, supporters of captive breeding were so enthusiastic that they “did not scrutinize the requirements of each species. The goal was captive breeding itself. Those who are concerned about the natural environment and wildlife. Was really tired of it. “
What is the probability that a captive breeding animal will return to the “wild”?Loss of genetic fitness
occurs early in captive breeding populations, with a high probability of occurring in several generations and loss of offspring. In the captive state, trait selection is performed within the population, and the survival rate in this environment increases, but
Wild survival does not increase.* Genetic fitness: Measured by the number of offspring born by individuals who have survived to reproductive ageThe purpose of most captive breeding programs is to reintroduce
animals, but captive breeding animals are actually self-sustaining, that is,
There are only a few cases that have returned to the “wild”.Whooping cranes still have to be taught how to move by human pilots.
* Reintroduction: Attempting to re-establish endangered or endangered species in areas where they lived in the past.
When it comes to amphibians, the success rate of reintroduction drops dramatically.In one study, of the 58 species reintroduced after captive breeding
Eighteen species were able to grow safely in the wild, of which 13 were able to become independent.
For that matter, of the 110 species raised under the captive breeding program, 52 were not planned to be reintroduced in the first place. The ecosystem in which these species lived has disappeared.
Should the species survive even if it cannot return to the wild?
Proponents of the habitat conservation method of conserving animals where they were born and raised say that captive breeding without a reintroduction plan is the most deadly in captive breeding. To reduce the risk of extinction as much as possible, the focus is on saving animals rather than the environment.“I’m not sure if animals can be reintroduced,” said Mark Michael, a professor of environmental ethics at Austin Peay State University in Tennessee. “Many environmentalists say,’If you capture a species from the wild, you shouldn’t capture it if you have little chance of reintroducing it.'”However, supporters of captive breeding have the idea that it is better to keep the seeds on Earth than to kill them. Even if the animals that remain in the zoo are basically treated as “spectacles,” as Michael says.