Donald Trump may not believe in climate change, but elephants do. And that belief has proved to be a trump card in their evolutionary progress because recent research has revealed that, over the course of evolution, the elephant’s brain has grown in size in direct relation to ancient periods of climate change.
As has our own. »
Like the elephant, our ancestors originated in Africa. Like the elephant, we migrated out of Africa to inhabit other continents. And, like the elephant, the size of our brain grew over time – most rapidly during times of dramatic climate change.
Across nearly seven million years, the human brain tripled in size. Most of the growth occurred in the past two million years. For the first two thirds of our history, the size of our ancestors’ brains was within the range of those of other apes living today. The final third of our evolution saw nearly all the action in brain size. Homo habilis, the first of our genus Homo who appeared 1.9 million years ago, saw a modest hop in brain size. The first fossil skulls of Homo erectus, 1.8 million years ago, had brains averaging a little larger than 600 ml. From here the species embarked on a slow upward march, reaching more than 1,000 ml by 500,000 years ago. Early Homo sapiens had brains within the range of people today, averaging 1,200 ml or more. And, as our cultural and linguistic complexity, dietary needs and technological prowess surged forward, so our brains grew to accommodate the changes.
As for the elephant, recent research by a team of scientists from South Africa, Europe and North America has revealed that their brains grew in two distinct phases, both of which appear to relate to climate change.
An elephant has the largest brain of any land animal. Until recently, however, scientists have struggled to determine why this should be so. The new team of researchers tackled the problem by applying cutting-edge scanning techniques and state-of-the-art statistical reconstruction of ancestral features to address the problem. And their research, which made use of a fossil record of elephants that included over 300 species, revealed the fact that the brain size of ancient elephants grew in two distinct ‘pulses’. One such pulse occurred 26 million years ago when Antarctica froze for the first time. This brought about a wave of global aridification that caused Africa’s dense rain forests to turn into savannah. The second pulse occurred 20 million years ago when the African climate became warmer and wetter and, for the first time, a land-bridge appeared, which linked Africa to Asia thus allowing the elephants to leave Africa and migrate in search of new habitats.
Both changes were crucial in the evolution of elephants in so much as they forced them to adapt to survive. 20 million years ago an elephant was a much smaller creature than it is today. Then it was about the size of a tapir. It also had a very short trunk. Modern elephants, on the other hand, weigh-in at around six tonnes, can be up to 4 metres in height and have trunks that are over 2 metres in length.
So, what prompted the elephant to expand so enthusiastically?The answer is that being BIG works for elephants. A large creature makes a predator think twice before attacking; a big body is also able to store more fat and water than a small one – especially when resources are short. A larger gut is also more efficient in digesting food.
But it’s not all about body size: brain size matters too. The elephant has a brain that weighs four times that of a human brain (elephant brains weigh 11-13 pounds, human brains weigh around 3 pounds) – and it has put that brain to extraordinarily good use.
Having a large brain, for instance, has allowed the elephant to work out how to migrate, where to find food, how to cope with new diets and, crucially, how to remember the location of distant waterholes during dry periods.
The size of its brain has also allowed the elephant to demonstrate a level of behavioral intelligence that is similar to our own. It manifests in a number of ways: the elephant has, for instance, one of the most closely-knit societies of any living species and elephant families can only be separated by death or capture.
Elephants exhibit behaviors associated with grief and mourning; with learning and mimicry; with play and altruism; with the use of tools and the ability to cooperate. They are also compassionate, cooperative, self-aware and communicative.
And finally, of course, it seems they’ve taken the concept of climate change on board.
The intelligence of elephants
Here are just some illustrations as to the power of the elephant’s brain:
Elephants have been observed digging holes to drink water and then ripping bark from a tree, chewing it into the shape of a ball, filling in the hole and covering it over with sand to avoid evaporation – then later going back to the spot for a drink. Elephants have also been known to drop very large rocks onto an electric fence either to ruin the fence or to cut off the electricity.
A 2010 experiment revealed that in order to reach food elephants can learn how to coordinate with a partner in a task requiring two individuals to simultaneously pull two ends of the same rope to obtain a reward.
Elephants are one of the few species of mammals that have any recognizable ritual around death. Elephants show a keen interest in the bones of their own kind and are often seen gently investigating them with trunks and feet while remaining very quiet.
Elephants show compassion to other creatures – even humans. George Adamson, of ‘Born Free’ fame used to tell the tale of an old Turkana woman who fell asleep under a tree after losing her way home. When she woke up, there was an elephant standing over her, gently touching her. She kept very still because she was very frightened. As other elephants arrived, they buried her under branches. She was found the next morning by the local herdsmen, unharmed.
Researchers at the University of Sussex in Brighton, UK have discovered that African elephants can distinguish differences in human gender, age, and ethnicity purely by the sound of someone’s voice. If the voice belongs to a person who is more likely to pose a threat, the elephants switch into defensive mode.