SHOULD WE BRING BACK EXTINCT ANIMALS? THE DILEMMA The return to Earth of extinct animals has made headlines again recently with the news that scientists have moved a step closer to bringing back the moa. OPINIONS Many animals are gone because of human error, so we need to use technology to recover them. Katsuhiko Hayashi, Biologist at Kyushu University, Japan At best it will produce a public cabinet of curiosities, at worst new pets for billionaires. George Monbiot, journalist and writer We ve got quite enough problems saving the species we ve got without bringing old ones back. Sir David Attenborough, naturalist and broadcaster The little bush moa, which became extinct in the 13th century, was a flightless bird that thrived in New Zealand. Scientists in the USA have pieced together the bird s DNA map, which means recreating the moa has just become more likely. Last year, scientists announced they were on the brink of resurrecting the woolly mammoth, a huge beast that roamed the Earth some 4,000 years ago. The scientist leading the deextinction effort said that a team of experts from Harvard University in the US was just two years away from creating a hybrid embryo. This embryo would see elements of the woolly mammoth programmed into an Asian elephant. The moa may soon be back on Earth The idea of bringing extinct animals back to life using science has been discussed for years. However, new, major advancements in DNA technology are making what were once dreams into realities. In 2003, a team of Spanish and French scientists brought a kind of wild goat known as a bucardo, or Pyrenean ibex, back from extinction. The goat was only able to survive for a few minutes, but it sparked a debate about de-extinction that has gone on ever since. Is it right to bring back animals that once roamed the Earth, or should we not meddle with nature? Should science instead focus on preserving those that are alive now? DEFINITIONS Embryo An unborn animal in the very early stages of growth. DNA Deoxyribonucleic acid. DNA carries the genetic code of a living thing that s all the information about how it looks and functions. Differences in this code make one living thing distinct from another. Extinction When a species no longer has any living members. Causes of extinction can be natural or due to human activity, such as hunting. De-extinction is the process of bringing extinct animals back to life.
CANDIDATE ANIMALS If scientists are to go ahead with de-extinction, probably their biggest dilemma will be deciding which species to bring back. What makes one animal deserve to be brought back to life more than another? FACTS & FIGURES The rapid loss of species we are seeing today is estimated by experts to be between 1,000 and 10,000 times higher than the natural extinction rate, which is what the rate of extinctions would be if humans were not around It is estimated that more than 5 billion species that once existed on Earth have become extinct There are nearly 100 animals on the World Wide Fund for Nature (WWF) list of critically endangered, endangered, vulnerable or near threatened species Around 100 species disappear from our planet every day, according to some estimates Scientists think at least 10 animal species have been made extinct in the past 200 years due to human activity Well, some scientists reckon that an animal s usefulness to the wider ecosystem (a community of organisms that interact with each other) plays a big part in deciding whether efforts should be made to bring it back. If one species is responsible for the wellbeing and survival of lots of other species, some scientists think it is worth de-extincting it. Another factor that some scientists think is important is timescale. If an animal became extinct more than 50 years ago, they argue, it would no longer fit in naturally on Earth as the environment has changed so much. Here are some of the likely de-extinction candidates: Woolly mammoth These giant creatures were up to 3.5 metres tall and weighed as much as 7 tonnes. Most mammoths died out about 10,000 years ago with the end of the Ice Age, but a small population were able to survive on the isolated Wrangel Island in the Arctic Ocean until 1650 BCE. Their closest living relative is the Asian elephant. Scientists who are trying to bring back the mammoth want to splice the animal s genes into elephant DNA using a gene-editing tool. The embryo would be partly an elephant, but include Could woolly mammoths roam the Earth once more? mammoth features such as small ears, long shaggy hair and blood that is adapted to cold weather. DEFINITION Genes Units that carry the information that determines an animal or human s features or characteristics. Genes can determine features like eye colour and some types of behaviour. They are passed down from generation to generation.
CANDIDATE ANIMALS CONTINUED Moa This large bird was unable to fly and used to be very common in New Zealand until its extinction around 600 years ago due to hunting and deforestation. Many plants in New Zealand once relied on the moa to spread their seeds, so its absence has had a big effect on the island nation s native flora. The area where the moa lived doesn t have many other species living there currently, so it might The moa flourish once more if it were made de-extinct. Now that researchers have almost completed the moa s DNA map, they plan to plant the moa s genes into the egg of another bird. If the egg successfully hatches, the moa will be back on Earth. Lesser stick-nest rat If the main reason to bring back an extinct animal is for its benefit to other creatures and the ecosystem, the lesser stick-nest rat is a top contender for de-extinction. It is thought it became extinct in the last few decades, after playing an important role in the Australian desert, where it built large nests using sticks. Some of these nests were as tall as one metre and up to three metres long. These nests also served as a home to loads of other creatures, like insects and reptiles. According to one expert, a large population of these rats could be built up in just fiveto-10 years if it were brought back. Dodo One of the most famous extinct animals, this ground bird inspired the expression dead as a dodo. Native to the island of Mauritius, the dodo was flightless like the moa and became extinct in the 17th century due to over-exploitation by humans and introduced species such as rats and pigs eating dodo eggs. In 2002, scientists worked out that the dodo belonged in the same family of animals as the dove and the pigeon. This means it may be easier to bring back the extinct bird than previously thought. The dodo is less significant in terms of the ecosystem, but it is a very popular The dodo extinct animal that many people would like to see alive once more. Aurochs A type of wild supercow, for thousands of years the aurochs were the largest land mammals in Europe, until humans reduced their numbers. The last of the aurochs died in Poland in 1627, which was one of the first recorded cases of extinction. Experts now say that the loss of the aurochs had a terrible effect on the overall variety of wildlife in Europe. They say that the aurochs large appetite for grazing provided a natural The aurochs gardening service that maintained landscapes and created the conditions for other species to thrive. A quagga at London Zoo in 1870 BIODIVERSITY HERITAGE LIBRARY Quagga A sub-species of the zebra, the quagga lived in South Africa until the 19th century. It looked like a cross between a zebra and a horse, with brown and white stripes on its head and neck, brown upper parts and a white belly, tail and legs. Quaggas became extinct in the wild due to hunting.
HOW DE-EXTINCTION IS DONE The first clone of a living animal was Dolly the sheep in 1996. Since then, scientists have cloned numerous creatures, including camels, cats, monkeys and rabbits. Creating new versions of extinct animals is a little trickier, as the species isn t around to take DNA from, or to act as a parent for the newborn animal. Biotechnology is the name given to the type of science that would be used to bring extinct animals back to life. Here are the three main de-extinction methods: DNA Dolly the cloned sheep Cloning The Jurassic Park technique, this involves taking a sample of DNA from a part of the extinct animal, which could be found in a fossil, or in bones kept in a museum. The animal s complete set of genes (known as a genome) is then reconstructed. This is what is currently being done with the moa. However, it is a difficult task as the embryo needs to be developed inside a mother who comes from an existing species that is as close as possible to the extinct one. The passenger pigeon Genetic engineering This would be possible for more recently extinct animals. If a close relative of a lost species is still alive, scientists can alter the genome to reverse engineer the extinct species. One species that might be brought back to life this way is the passenger pigeon, which has been extinct since 1914. Scientists would use its closest living relative, the band-tailed pigeon, and study the genome of it and the extinct bird. They d work out the differences and then alter the genome of the band-tailed pigeon to genetically engineer a new bird that is identical to the passenger pigeon. However, there isn t any guarantee that the new passenger pigeon would have the same behaviour as the original. Cross-breeding This method involves recreating a species by getting existing species to mate in order to gradually restore the genome and physical makeup of the extinct animal. Scientists are developing this technique to bring back a type of cow that is very similar to the aurochs. They think this could be a better way of de-extincting because it would use animals that are already adapted to the modern world, rather than trying to recreate an animal from a very different time.
WHAT ABOUT THE LIVING? De-extincting is all well and good, but it s expensive and time-consuming. There are scientists who think that resources, money and time would be better spent trying to keep our endangered species alive. There are several animals at risk of extinction, such as rhinos, the orangutan and the Bengal tiger. Instead of focusing on bringing back those that have already gone, should science not be putting all its efforts into protecting those who still live? A Bengal tiger in the wild The orangutan is at risk of extinction THE DANGERS OF PLAYING GOD Is it up to humans to play God by controlling life in this way? Some people think that just because we can, it doesn t mean we should. They argue that, although some species have become extinct due to human behaviour and climate change, many have not, and it is not our place to control and change the course of nature. Is it a good thing to decide which animals from Earth s past get to live again, and which don t? There is also a danger that comes with playing God. Many animals that are now extinct lived hundreds of years ago, when Earth was a very different place. They roamed the planet at a time before factories, planes and cars, when the population was much smaller than today s 7.5 billion. A lot of extinct animals may not be able to cope on Earth anymore. As a result, bringing them back may lead the animals to suffer. This would be cruel.
YES, WE SHOULD BRING BACK EXTINCT ANIMALS NO, WE SHOULDN T BRING BACK EXTINCT ANIMALS 1. THE SCIENCE LEARNED WOULD BE HUGE The processes by which scientists could bring back extinct animals would signal a major leap forward for science. We can learn so many useful skills and techniques that could be applied to other areas of science, such as human medicine. 2. HUMANS SHOULD MAKE UP FOR PAST MISTAKES Humans have contributed a great deal of pollution to Earth, and human activity, such as hunting, has been directly responsible for some extinctions. Bringing back animals that have been wiped out by our actions is the least we can do. 3. IT WOULD HELP THE WIDER ECOSYSTEM It s not just that it would be cool to see extinct animals roaming the Earth again; they can also contribute to the wider ecosystem and help other animals and plants thrive. 1. LET S FOCUS ON PREVENTING EXTINCTION So many species are at risk of extinction right now. Our efforts and money would be better spent protecting endangered animals rather than bringing back those who have already gone. 2. THE ANIMALS MAY NOT COPE WELL It s dangerous to play God. We could have good intentions, but bringing back some animals to a new and very different planet than the one they once lived in could harm them. 3. WE SHOULD NOT MESS WITH NATURE Extinctions are an unfortunate aspect of life on Earth. It is not up to humans to interfere with nature s course.
What should our priority be: protecting the living animals, or bringing back the dead ones? If it s OK for humans to stop sick animals from dying, is it OK for humans to bring back extinct animals? Is cloning animals acceptable, or could it be dangerous? Would you be interested in seeing extinct animals like the moa or quagga on Earth once more? Do some animals deserve to be brought back from extinction more than others? Should scientists only bring back animals made extinct by human behaviour, rather than natural causes? If you had to choose, which animal would you bring back from extinction? Is it right that we alter nature by bringing back species that have been gone for centuries?