Who is Animal of the Year 2021?

if

Choose one for the past 2021

Animal of the Year

Who do you think of?

It is a Siberian tiger that entered the village from Heilongjiang

It was a snow leopard that strayed into a sheepfold in Qinghai

Or is it the leopard that escaped from Hangzhou?

According to the Planetary Research Institute

Whether it is attention or influence

Animal of the Year 2021

It’s none other than the elephant

Elephants migrating north from Yunnan

Let the elephant completely enter our field of vision

(Elephants on the African savannah, photographer @Huang Lisheng)

▼

When you stare at an elephant

It will definitely be

Height 1.9~4 meters, weight 2.4~6 tons

Shocked

(An adult Asian elephant appeared in a tea garden in Pu'er, Yunnan. Its huge size can give people a strong sense of oppression. Photographer @何新闻)

▼

When you go deep into the inner world of an elephant

It will definitely be

Rejoice for the new life and mourn for the departure

Moved by

(A young African savanna elephant is using its trunk to grab a handful of plants and raise them to its eyes, perhaps using them to drive away mosquitoes. Photographer @贾纪谦)

▼

When you look back at the elephant family history

It will definitely be

From humble beginnings to greatness

From glory to obscurity

Attracted

(Please watch in horizontal mode, elephant family tree, drawn by @Han Qing & Chen Sui/Planet Research Institute)

▼

Let's do it together

Gaze, look deep, look back

The Elephant's Past

Re-understand this

Fantastic land beast

01

Rise of the Lox

Elephant's

Proboscidea

Named after its long nose

But back 60 million years ago

Earliest known proboscidean group

Apatosaurus

(Phosphatherium spp.)

No long nose

The size was also far less than that of today's elephants.

Based on incomplete fossil fragments

It's just a 10-15 kg

Small

(The picture shows a newborn African savanna elephant protected by the huge body of its family. The weight of the newborn elephant is close to 100 kilograms, which has crushed all the little friends in the star institute. Source: Visual China)

▼

However

Changes in climate and environment

This little guy found it by accident.

A way to turn things around

Get bigger

(The Sahara Desert, the world's largest desert in northern Africa, is the origin of Proboscidea. Many early Proboscidea members, including Apatosaurus, were discovered here. Source: Visual China)

▼

About 40 million years ago

There is no Sahara Desert in the north of the African continent

On the contrary, this is a wet lake wetland.

Proboscidea living here

Archaeoelephant

(Moeritherium spp.)

Still without a proboscis, they resemble domestic pigs

The height at the shoulder is less than 1 meter and the weight is more than 200 kilograms.

The tender water plants in the water are their main food.

(The Proto-Elephant was once considered to be the earliest proboscidean animal and the ancestor of the elephant, and was named after it. This cognition was changed until the discovery of the Apatosaurus, but the name of the Proto-Elephant has been retained. Map by @Hanqing/Planetary Research Institute)

▼

The climate has become increasingly dry since then.

Lake wetlands are gradually replaced by forest grasslands

Tender aquatic plants are becoming increasingly scarce

Proboscidea animals eat

I had to eat the hard plants on the shore instead.

The new food is harder to digest than water plants

To prolong digestion time

More fully absorb nutrients from grass leaves

Individuals with larger digestive systems have the upper hand

So their size grows bigger and bigger

(An elephant eating leaves, photographer @段黄德)

▼

About 20 million years ago

Body size of proboscidean animals

Close to today's elephants

Over the next 10 million years, the mountains and rivers underwent dramatic changes.

They migrated from Africa to other continents

Develop more members and evolve into more groups

The golden age of proboscidea began

(Historical diffusion routes of Proboscidea, map by @Chen Zhihao/Planetary Research Institute)

▼

Golden Age

Gomphotherium

Throughout Europe, Asia, Africa, and the Americas

Among them

Gomphotherium

(Gomphotherium spp.)

The lower jaw is long and pointed

Like being "embedded" between the two long teeth in the upper jaw

(Reconstruction diagram of Gomphotherium, drawn by @Hanqing/Planetary Research Institute)

▼

There is a very special species in the family Gomphotherium

Their jaws are extremely stretched

Plus the flat lower incisors in front

Like a giant shovel

Can be used to shovel food such as tree bark

It is figuratively called

Shoveltooth

(Platybelodon spp.)

(Schematic diagram of the restoration of the Shovel-toothed Elephant, drawn by @Hanqing/Planetary Research Institute)

▼

In the same period, Eurasia and Africa

There is also an ancient group of proboscidae living

Deinotherium

(Deinotherium spp.)

They were early in the period of the proto-elephant

He parted ways with other members and evolved on his own.

The lower jaw has a pair of distinctive downward-curving tusks

Can be used to dig roots or peel bark

Some members of this group were taller than today's elephants.

Huge size and strange tusks

This gave them the name "terrible beasts"

(Reconstruction diagram of Deinotherium, drawn by @Hanqing/Planetary Research Institute)

▼

The golden age lasted until

About 5 million years ago

The climate is getting drier and colder.

Mountains and seas change dramatically, and vegetation changes color

Highly dependent on the original environment and unable to respond

Many members of the order Proboscidea

Stop here

Afterwards

The baton of the family's main force was passed to a

Short jaw, no lower incisors, short and flat skull

Proboscidea

Elephantidae

(Elephantidae)

(Comparison of long mandible and short mandible, map by @Hanqing/Planetary Research Institute)

▼

Members of the elephant family, shining stars

About 3 million years ago

In Gansu and other Yellow River basin areas in my country, there are

Stegodon shi

(Stegodon zdanskyi)

Yellow River elephant

They can reach up to 4 meters in height and nearly 8 meters in length.

It is one of the largest members of the order Proboscidea.

Their tusks are about 2 meters long.

Like two long swords

(Reconstruction diagram of the Stegodon shii, drawn by @Hanqing/Planetary Research Institute)

▼

About 200,000 years ago

In the Yangtze River and Yellow River areas of my country, there are

Nama elephant

(Palaeoloxodon namadicus)

Based on a femur fossil from India in 1834

The Nama elephants were probably over 5 meters tall and weighed more than 20 tons.

This is 3 to 4 times the weight of today's elephants.

Their tusks are often more than 3 meters long.

Probably the largest elephant in the world

One of the largest land mammals ever recorded

(Namaste giant femur fossil, femur material source @Wikimedia Commons, map @Hanqing/Planetary Research Institute)

▼

The most famous prehistoric giant of the elephant family is

Mammoth

(Mammuthus spp.)

Huge size, huge tusks, thick long hair

This is the impression most people have of mammoths.

But in fact

In addition to the well-known woolly mammoth, the true mammoth

There are many types of mammoths, and they vary in size.

From the Siberian Ice Sheet to the European Islands

There are mammoths

(The name "Mammoth" comes from the Tatar language in Siberia, which means "underground dweller". The following figure is a restored schematic diagram of three types of mammoths of different sizes. Design @Han Qing/Planetary Research Institute, map @Chen Zhihao/Planetary Research Institute)

▼

However

With the climate change caused by

A sharp decline in habitat and food

and hunting by early humans

About 4000 years ago

The last mammoth

Fell in the cold wind of Siberia

(Skeleton fossil of the southern mammoth (Mammuthus meridionalis) exhibited in the Paleontology Museum of the National Museum of Natural History of France, source @Wikimedia Commons)

▼

So far

The only one left in the large Proboscidae family is

Today's elephants

(Schematic diagram of the evolution of the main species of Proboscidea, drawn by @Hanqing/Planetary Research Institute)

▼

They are divided into

3 species

At a Glance

Long nose and big ears, it's hard to tell you from me

But they are actually quite different

(Please watch in horizontal mode, a diagram comparing the morphology of the three types of elephants. Note that the morphological differences of ivory in reality are not significant. This is for reference only. Map by @陈随/星球研究院)

▼

Today's elephants

How has it stood the test of time?

What abilities do they have?

02

"Big" shows its prowess

first

Elephants have a long and flexible

trunk

The weight of their skulls

Almost 1/4 of the entire skeleton

Therefore, a long neck like a giraffe is not suitable for elephants.

As an alternative

The long nose was born

(Comparison of how elephants and giraffes feed on the leaves of tall acacia trees, image source: @Visual China, photographer: @Cheng Xiaomin)

▼

The trunk is the combination of the upper lip and the nose.

It is made up of more than 40,000 muscles.

More than 60 times the amount of muscle mass in a human body

This makes the trunk weighing more than 100 kilograms

Strong and flexible, powerful functions

It can not only explore and communicate, but also grasp and absorb water.

The single water absorption capacity can reach up to 12 liters

(The trunk of an African elephant fetching water, with two obvious nasal protrusions visible at the end, photographer @戴频)

▼

Secondly

Elephants developed a special pair of upper incisors

ivory

It is not only an important weapon in fighting

It also has multiple uses in daily life, such as knives, forks, prying shovels, etc.

(Two African elephants fighting, source: Visual China)

▼

Furthermore

Beyond Ivory

Up, down, left, and right in the elephant's mouth

Each has a huge molar

molar

Elephant molars have powerful chewing ability

And you have 5 chances to get a new one in your lifetime

(The molars in the mouth of an Asian elephant. The left and right sides of the picture are each a whole molar. The ridges on the molars are an important morphological feature for distinguishing and identifying Proboscidea species, and are also a key structure for grinding food. Source: Visual China, map by Hanqing/Planetary Research Institute)

▼

The way elephants replace their molars is very special

Unlike human teeth, which grow from bottom to top,

The molars of elephants grow from back to front.

It's like a conveyor belt under the gums.

The new teeth replace the old teeth from back to front

The last molar of the Asian elephant

Replacement is completed around age 40

Since then, as the molars have worn away,

It gradually loses the ability to chew food

Life also came to an end

(Schematic diagram of elephant molar replacement, drawn by @Chen Sui/Planet Research Institute)

▼

With the help of molars

Elephants have a wide range of diets

Wild Asian elephants eat nearly 240 plant species

Foxtail grass, wild banana and various bamboos, etc.

Flowers, fruits, grass, trees

Almost all of it is the elephant's meal.

Elephants are also big eaters

Spend about 8 hours a day eating

Eat 160-300 kg of food a day

That's 100 times more than what we eat in a day.

They are either eating or on their way to find food.

(Asian elephants eating, photographer @黄力生)

▼

also

Elephants have another very important organ

Elephant Ear

The average thickness of an elephant's skin is 2.5-3 cm.

10 times thicker than human skin

Most of the skin on the body does not have sweat glands.

Plus living in tropical and subtropical areas

This makes cooling a big problem

(Elephants are typical thick-skinned animals. African elephants have deep wrinkles on their skin, which have magical effects such as water retention. Source: Visual China)

▼

This is when the huge elephant ears are particularly important.

Elephants flap their ears to cool the blood

As blood circulates throughout the body

This will cool down the whole body

(An African savanna elephant cub has huge ears, photographer @刘思尧)

▼

besides

Elephants use their trunks as shower heads

There are also grass baths, mud baths, sand baths, etc.

Various sun protection and cooling activities

(Mud baths can both cool down and repel insects, and are a social activity that elephants love very much. Source: Visual China)

▼

Trunk, tusks, ears

These special external organs help elephants

In harsh environment and long time

Survive

And more importantly

Elephants also have a wealth of

The Inner World

03

Big has brains

Elephant brain

The average weight is 5 kg, which is 4 times that of the human brain.

It has the largest brain of any land animal alive today.

(The Asian elephant has the best intelligence among the three known elephant species. The bump on their head is also called "smart tumor". Photographer @贾纪谦)

▼

Although big doesn't mean smart

But according to the evaluation of animal intelligence

Encephalization quotient (EQ)

Elephants are indeed very smart animals

The Asian elephant is the smartest of the elephants

Their EQ is over 2.0

Although there is still a gap with the human EQ of 7.0

But it is already twice the average level of mammals

The intelligence level is comparable to that of chimpanzees

(Chimpanzees living in the African jungle are the animals with the closest genetic relationship to humans, source @Visual China)

▼

Elephants' amazing brains

First of all, it manifests itself as extraordinary

memory

Elephants can remember every face in their herd

This makes it possible for elephants to use facial recognition to pass through

They can also remember the location of water sources within hundreds of kilometers.

Help them complete long-distance migration

(Please watch in horizontal mode, a group of African elephants drinking water by the pond, photographer @周伟东)

▼

Secondly, elephants have excellent

Logical ability

We usually think

"Tool use" is a specialty of primates

However, the elephants expressed no pressure at all.

They are skilled in using tools such as branches.

Repel mosquitoes, scratch itches, and even do pedicures

Not only that

Imagination

It also works amazingly on elephants

They can understand the meaning of "directional movements"

Can extend in the direction pointed to find the pointed object

This seemingly simple act

It is an important indicator for researchers to evaluate animal imagination

This is an ability that even chimpanzees do not have.

(An adult Asian elephant stretches its trunk, photographer @贾纪谦)

▼

The hippocampus in the elephant's brain

Let the elephant express

Rich emotions

They sympathize with the plight of other animals.

And have a sense of justice to help others

(People have recorded many incidents of elephants in Africa helping other animals out of trouble, photographer @Teng Hongliang)

▼

When you encounter animal carcasses on the road

Shows a stronger interest in the remains of their own kind

When a closer family member dies

The elephants will even stay by the carcass for days.

And uttered a mournful wail

Like a grand funeral

(An adult African savannah elephant is guarding the body of a baby elephant, source @Visual China)

▼

Elephants are affectionate and have a clear distinction between love and hate

If elephants are attacked by humans

They will probably attack human villages.

Like an act of angry revenge

(An African savannah elephant seems to be brewing emotions, source @Visual China)

▼

Elephants can have such a rich inner world

It's not just a good brain that matters

More importantly, they have similar

Social

(African savanna elephants in Namibia, source: Visual China)

▼

Elephant herds are a matriarchal society

Led by experienced older female elephants

It consists of young elephants and adult female elephants.

Male elephants are driven out of the herd when they reach adulthood.

Travel alone or in small "bachelor groups"

The only time they interact with elephants is during the breeding season.

(A lone adult male African elephant, source: Visual China)

▼

The size of the elephant herd ranges from a few to hundreds of elephants.

The home ranges from tens to tens of thousands of square kilometers.

This makes the teamwork ability of the elephant herd particularly important

But how can we maintain the coordination and unity of the elephant herd?

(Please watch horizontally, a herd of African savanna elephants in front of Mount Kilimanjaro, source @Visual China)

▼

The elephant's answer is

communicate

Elephants communicate through a unique language system

It is made up of smells, sounds and movements

This "elephant language" allows them to communicate no matter how far apart they are.

Maintain a close collaborative relationship

(The relationship between elephant herd members is very close, and they have a complex way of communication, source @Visual China)

▼

When face to face

Elephants have rich body language

Rapidly flapping ears

Usually a sign of happiness and relaxation in elephants

The trunk points to the other's mouth

Usually it's a sign that they're showing good will to each other.

(In Africa's Amboseli Park, a young savannah elephant is showing goodwill to another elephant. Photographer: Teng Hongliang)

▼

Hold your head high and shake your head

Maybe they felt threatened.

Ready to give it a go

(In Madikwe Game Reserve, South Africa, an adult savanna elephant bravely drives away a pack of African wild dogs to protect the cubs in the family from the threat of these predators. Source: Visual China)

▼

When the distance is one hundred meters

Elephants can communicate through smell and other methods

The number of olfactory genes in African elephants

Twice as much as a dog and five times as much as a human

Can easily smell odors from a hundred meters away

Always keep track of any movement a hundred meters away

(In a tea garden in Pu'er, Yunnan, a wild Asian elephant is raising its nose to sniff the surroundings. Source: Visual China)

▼

If the distance is kilometers

Voice became the main form of communication

A distance of tens of kilometers requires a very penetrating sound

For example, infrasound with a frequency below 20 Hz

In fact, many animals, such as whales, can sense infrasound.

But there are only a few animals that can both sense and emit infrasound.

Elephants are one of them.

(Like elephants, whales can also sense infrasound. This picture shows a Bryde's whale in the Beibu Gulf eating with its mouth wide open. Photographer: @赖建)

▼

If the distance is further

Is there nothing the elephant can do?

Not really

Elephant feet are extremely sensitive

Can sense earthquake waves hundreds of kilometers away

Perhaps the elephants in Beijing and Tianjin are secretly communicating with each other every day.

The researchers inferred that in this way

Elephants can predict rainfall and food conditions along their migration routes

Make travel plans in advance

(African grassland elephants in front of Mount Kilimanjaro, photographer @陈小琳)

▼

A person with extraordinary bones and special skills

Resourceful, compassionate and righteous

Such a "treasure animal"

It is worth cherishing by us humans

However

The reality is not so

04

"Big" is not as good as others

Now living on Earth

About 400,000 African elephants

About 60,000 to 150,000 African forest elephants

and about 40,000 to 50,000 Asian elephants

All together they are less than human beings

One in ten thousand

(A female African savanna elephant with two baby elephants. Elephants usually give birth to only one baby elephant per litter, and twins are relatively rare. Photographer @黄力生)

▼

As human footprints spread across the world

The distribution range of elephants

But from across Europe, Asia, Africa, America

All the way down to Africa and southern Asia

(Sketch of changes in the global distribution of elephants, map by @Chen Zhihao/Planet Research Institute)

▼

in

African savanna elephants are the most widely distributed and have the largest number of

They live in the vast African savannah

The most common type of elephant seen in the media

(The vast savannah in Serengeti National Park is a typical habitat for African elephants, source: Visual China)

▼

The forest elephant, also found in Africa

Lives only in the dense jungles of central Africa

Because it has been overshadowed by the African elephant for a long time

They were not first described scientifically until 1900.

(Typical habitat of African forest elephants, source: Visual China)

▼

Asian elephants, as the name suggests, are found in Asia

Today they are found only in the jungles of southern Asia.

It is the only elephant species distributed in my country.

Southern Yunnan in my country is the northern edge of their distribution.

(An "elephant father" from the Wild Elephant Valley in Xishuangbanna, Yunnan, is leading his "students" into the jungle for wild training. Author/Source @康平/中国新社/Visual China)

▼

However, back to the Shang and Zhou dynasties

You can even see wild Asian elephants in Hebei Province.

During the Spring and Autumn Period and the Warring States Period, Asian elephants could reach the Huaihe River area.

In the Tang Dynasty, it came to the south of the Yangtze River

The Song Dynasty retreated to Lingnan

(The Shang Dynasty bronze elephant statue collected in the Hunan Provincial Museum, the bulge on the top of the head and relatively small ears are typical characteristics of Asian elephants, which shows that the image of Asian elephants was deeply rooted in people's hearts in the Shang Dynasty. Photographer @见书)

▼

There were records of wild Asian elephants in Guangdong and Guangxi in the 19th century.

But only 200 years have passed

Only southern Yunnan still has wild Asian elephants.

Asian elephants have been

Retreating southward at a rate of 0.5 degrees of latitude per 100 years

What exactly happened?

(Distribution changes of wild Asian elephants in my country throughout history, map by @Chen Zhihao/Planet Research Institute)

▼

“Survival of the fittest”

It is a normal law of nature

But what happened to the elephants was not normal.

Factors that affect elephant survival

Not only nature, but also humans

(An underage Asian elephant with shackles and chains. The elephant hook in the hands of the elephant trainer is a sharp weapon to make it obedient. Photographer @段黄德)

▼

African elephants

Always struggling under the gunpoint of humans

Their huge tusks

It has long been a target of poachers.

Asian elephants have relatively small tusks and are more secretive

Therefore, ivory poaching poses relatively little threat to Asian elephants

Before 2015

Nearly 35,000 elephants are killed every year worldwide

Today, more and more male elephants no longer have huge tusks.

This is the result of human intervention in "natural selection"

(In the last century, a warehouse storing ivory seized from illegal poaching, source: Visual China)

▼

Asian elephant

Although I escaped from the ivory hunters

But it still cannot escape the fate of extinction

Because in densely populated Asia

Human-elephant conflict, habitat destruction and domestication

The main threat to wild Asian elephants

(Wild Asian elephants foraging in a garbage dump, author/source @People's Vision)

▼

With the development of human activities

Large areas of Asian elephants’ original habitats have been occupied

Human-elephant encounters are frequent and human-elephant conflicts are becoming more serious

In parts of Southeast Asia

People even used burning tires to drive away elephants

Or take extreme measures such as burying explosives in elephant food to retaliate against elephants

The conflict has evolved into our country and other countries and regions

The main factors threatening the survival of Asian elephants

To protect the ecological environment

Now we are starting to return farmland to forest

But little did they know that the forest of giant trees

Not an ideal habitat for Asian elephants

They prefer scattered open spaces of varying sizes.

Rich in low shrubs

Mosaic Jungle

(The clearing in the forest is the most important activity place for wild Asian elephants, source @Visual China)

▼

Domestication

Another major threat to Asian elephants

They are smarter and more docile than African elephants

Therefore, it has been widely used for a long time.

Hard labor, performance, and war

(The character “为” in oracle bone script is composed of “手” and “象”, which means “people lead elephants to work”. It can be seen that the history of elephant training has begun since the beginning of China. Map by @陈随/Planetary Research Institute)

▼

Most of the elephants

All are caught in the wild

Not artificial breeding

Because the gestation period of Asian elephants is nearly 2 years

It takes 3-4 years for baby elephants to form a working population

Artificial breeding of elephants is very costly and technically demanding

(In Nepal, there are still a large number of Asian elephants used to carry heavy objects. Photographer: He Xiaoqing)

▼

Although it is no longer necessary

Elephants farm and fight for us

But in zoos, circuses and tourist attractions around the world

There are still about 15,000 domesticated elephants.

They may be imprisoned in a fence.

Or put on heavy shackles

This is using their life's grievances

In exchange for people's temporary happiness

(Asian elephants performing in a circus, photographer @万崲)

▼

Not only should

We also need more

Rediscovering the Elephant

Try to find an opportunity

Take a good look at an elephant

Then you can feel it more

The vicissitudes of elephant history

The wonders of natural life

as well as

The beauty shared by humans and elephants

Those innocent

Those fearless ones

…

(Back view of African savanna elephant mother and child, source: Visual China)

▼

As humans become more powerful today

The era of giant beasts is long gone

But the elephant story is still

Far from over

This article was created by

Written by: Zuokou

Editor: Quasimodo by the River

Image: Pan Chenxia

Map: Chen Zhihao

Design: Han Qing, Chen Sui

Source of header image and 1:1 cover image: Visual China

Reviewers: Quasimodo by the River, Zhang Zhao, Zheng Yi

Expert reviewers: Yu Qiupeng, Huang Cheng, Wang Wei

Main references of this article

[1] Chen Mingyong, Wu Zhaolu, Dong Yonghua et al. Research on Asian Elephants in China[M]. Beijing: Science Press, 2006.

[2] Jiang Zhicheng, Li Zhengling, Bao Mingwei, Chen Mingyong. Statistics and analysis of plant species consumed by Asian elephants in China[J]. Acta Theriologica Sinica, 2019, 39(05): 514-530.

[3] Li Chun, Cao Dafan. Review and reflection on the history of Asian elephant protection in China[J]. Forestry Construction, 2019(06):6-10.

[4] Liu Minggang. Explanation of Chinese characters: “象”[J]. Calligraphy, 2020(04):137.

[5] Ivan Mauk. The Retreat of the Elephants: An Environmental History of China. Translated by Mei Xueqin et al. Nanjing: Jiangsu People's Publishing House, 2014.

[6] Zhang Feng. The origin and evolution of elephants[J]. Biological Evolution, 2014(03):29-33.

[7] Zhou Fangyi. Chinese elephants: a huge and intelligent family[J]. Forests and Humans, 2019(06):10-31.

[8] Asier Larramendi. Shoulder Height, Body Mass, and Shape of Proboscideans[J]. Acta Palaeontologica Polonica, 2016, 61(3).

[9] Benz A. (2005) The elephant'shoof: macroscopic and micro-scopic morphology of defined locations underconsidera-tion of pathological changes. Inaugural Dissertation, Vetsuisse-Fakultät Universität Zürich.

[10] Ba Tes LA, Poole JH, Byrne RW. Elephant cognition[J]. Current Biology, 2008, 18(13):R544-R546.

[11] Cardillo, Marcel, Mace, et al. Multiple Causes of High Extinction Risk in Large Mammal Species.[J]. Science, 2005.

[12] Erich Thenius. The Distribution of Proboscidea (Elephants) [J]. Kosmos, 1964: 235-242.

[13] Gheerbrant, E., Sudre, J. & Cappetta, H. A Palaeocene proboscidean from Morocco. Nature, 1996, 383, 68–70.

[14] Grubb P , Groves CP , Dudley JP , et al. Living African elephants belong to two species: Loxodonta africana (Blumenbach, 1797) and Loxodonta cyclotis (Matschie, 1900)[J]. Elephant, 2000,2(4):1-4.

[15] Johnson CN Determinants of loss of mammal species during the Late Quaternary 'megafauna' extinctions: life history and ecology, but not body size [J]. Proc. R. Soc. Lond. B. 2002, 269: 2221–2227.

[16] Meyer M., Palkopoulou E., Baleka S., et al. Palaeogenomes of Eurasian straight-tusked elephants challenge the current view of elephant evolution[J]. eLife, 6:e25413.

[17] Niimura Y , Matsui A , Touhara K . Extreme expansion of the olfactory receptor gene repertoire in African elephants and evolutionary dynamics of orthologous gene groups in 13 placental mammals[J]. Genome research, 2014, 24(9):1485-96.

[18] Peiris U , Padmalal U . Assessment of the landscape characteristics of the habitat of wild elephants in Sri Lanka[J]. Proceedings of International Forestry & Environment Symposium, 2012.

[19] Palkopoulou E, Lipson M, Mallick S, et al. A comprehensive genomic history of extinct and living elephants. Proc Natl Acad Sci US A. 2018 Mar 13;115(11):E2566-E2574.

[20] Roth, G., and Dicke, U. (2005). Evolution of the brain and intelligence. Trends in cognitive sciences 9, 250-257.

[21] Shoshani J, Eisenberg JF. Elephas maximus[J]. Mammalian Species, 1982(182):1-8.

[22] Shoshani J. Understanding proboscidean evolution: A formidable task[J]. Trends in Ecology & Evolution, 1998, 13(12):480-487.

[23] Tsien, JZ (2015). A Postulate on the Brain's Basic Wiring Logic. Trends in neurosciences 38, 669-671.

Planetary Research Institute

Deconstruct everything in the world and explore the ultimate world

···THE END···