The next extinctions
The death of the world’s last male, northern white rhino has highlighted Earth’s huge extinction crisis. Just how many species are at risk — and what can be done to save them?
So, the northern white rhino is extinct?
Pretty much. The last male, named Sudan, died aged 45 in 2018. Two females remain, meaning the only hope of reviving the population is through scientific intervention via IVF.
Why is this type of rhino so rare?
There are five species of rhinoceros — the second largest land mammal on Earth after elephants. The white rhino consists of two sub-species: the southern white rhino, and the much rarer and critically endangered northern white rhino.
The sub-species’ population in Central Africa was largely wiped out during the poaching crisis of the 1970s and 1980s. Poaching was fuelled by demand for rhino horn for use in Chinese medicine, and for dagger handles in Yemen.
Southern white rhinos, of which there are around 20,000, have fared better due to tougher laws on poaching in the countries they inhabit. They are classed as “near threatened”, while most other types of rhino are “critically endangered”.
Which other animals are critically endangered?
Some species are down to just a few thousand individuals: there are 2,800 Sumatran elephants left, along with about 1,000 Yangtze finless porpoises. Then, you move into the hundreds: there are 700 mountain gorillas left in the wild, and just 340 Malayan tigers.
Then, there are the creatures so rare that every single animal could fit into one large room. These include the world’s 57 Amur leopards, and 30 vaquitas (another type of porpoise).
In total, 2,464 animal species are critically endangered.
How do we know these numbers?
When counting land mammals, conservationists will use a combination of GPS trackers, disguised cameras, traces of kills, faeces, paw marks and scratches on trees. They, then, do a calculation using this information alongside estimates based on factors like the availability of prey, and how many individuals could be sustained in a given area.
But the numbers seem very specific…
They are indeed controversial. For example, scientists are divided on whether snow leopards are still endangered species. Some big cat experts say their population has stabilised and increased in a number of places. Others argue that there has been no robust scientific study to prove this.
How do we define “endangered”?
It is not just about numbers. Several factors are important. For example, are they all living in one area? If they are, they are more likely to be wiped out by one single cause than if they were spread out geographically.
What are the range of threats they face? How long is their reproductive cycle — and, therefore, how quickly could their population recover if there were enough breeding pairs? The genetic diversity of a population is also a factor. If it is not diverse enough, too much inbreeding will lead to yet more challenges for the species in the future.
So what can we actually do?
Writing for CNN, scientist John D. Sutter sets out a five-point plan to prevent the sixth mass extinction event:
1. Stop burning fossil fuels. Doing so, heats up the atmosphere, creating trouble for all corners of the natural world.
2. Protect half the surface of the Earth. Some 84% of species could be saved if we protected an area that large.
3. Fight illegal wildlife trafficking. Some of the world’s most iconic species are threatened simply because people sell their body parts on the black market.
4. Slow human population growth. There will be nearly 10 billion humans by 2050. Humans are the main drivers of the current mass extinction.
5. Reconnect with the natural world. Underlying all this is the fact that humans have lost touch with nature.
- Answering honestly, how much do you really care about the plight of the northern white rhino?
- Create an advert asking for help to save an endangered animal. Explain how and why it should be saved.
- Two females
- Sudan’s daughter and granddaughter.
- Stands for “in vitro fertilisation”. It is the process of fertilisation, where an egg is combined with sperm outside of the body.
- Critically endangered
- Species are divided into seven categories: least concern, near threatened, vulnerable, endangered, critically endangered, extinct in the wild, extinct.
- Yangtze finless porpoises
- A porpoise is a type of small-toothed whale that is very closely related to oceanic dolphins. The Yangtze is a river in China.
- Amur leopards
- Amur leopards are slightly larger than normal leopards, and inhabit the forests of Russia near its border with China and North Korea. The Amur is a river.
- 2,464 animal species
- There are also 2,104 critically endangered plant species.
- Sixth mass extinction event
- Meaning that three-quarters of all species go extinct forever. This will be the first such event to have been caused by humans.
- Half the surface of the Earth
- Currently, only 15% of land and 4% of the world’s oceans are protected from encroachment by humans, mostly in the form of farms.