Navigating landscapes for survival could have created bigger brains.
This article demonstrates how animals have evolved over time to suit their environment. It shows how technology, alongside an understanding of Physics and Biology, can be used to learn about this and the impact it has on society today. It is best suited to students in years 5, 9, and 10 who are studying Biological and Physical science.
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When it comes to superpowers, humans have dreamed up everything from super strength and X-ray vision to body morphing, shape shifting, and spinning giant spiderwebs.
Planning ability might not sound quite as sexy, but according to Malcolm MacIver, from Northwestern University, US, it’s our species’ true superpower.
Writing in the journal Nature Communications, he and Ugurcan Mugan suggest complex terrestrial landscapes with trees, bushes, rocks and hills, and the primal drive to survive, is what made land animals smarter than their aquatic ancestors.
The idea came to MacIver when pondering why land animals have superior vision to sea critters.
“One of the most exciting discoveries of my scientific life came a few years back when we made computer simulations of how far ancient animals could see through the air and through water,” he says.
“We were able to provide evidence that just before our distant ancestors – around 380 million years distant – lurched onto land from only living in the sea, their eyes tripled in size.”
Combined with fossil data, the simulations suggested these animals hunted like crocodiles, peering out of the water to see hundreds of times further than they could in water, which rapidly absorbs and scatters light.
This likely led to them chasing tasty insects onto land, eventually evolving their limbs and other features needed to survive.
“What this work really showed us,” MacIver says, “was that vision, one of our most prized ways to take in the world, went from being relatively unimpressive while in water… to giving us information about a much, much larger span of space once we lived on land.”
This enhanced vision offers more time to plan ahead rather than react automatically.
“Think of driving at night in the fog and seeing a deer just in time to swerve, versus seeing an exit for food and gas on a highway from a long way away and thinking about whether you want to make a stop now or closer to when you get to grandma’s house,” MacIver posits.
“Seeing further away affords you the time and space to ‘think further away’ as well.”
To test this, he and Mugan tapped into computational models, such as the famous AI program AlphaGo, to simulate predator-prey interactions.
They made complicated adaptions to the models to ask the question, “does life on land favour planning or habit?”
“Life” is represented by a checkerboard, where some squares are open and you can move forward, backward, left or right by one square, and others are closed – you can’t move through them or see your opponent.
“There is a ‘prey’ that needs to get to a goal,” MacIver explains, “and an unrelenting ‘predator’ that is trying to eat it.”
What they sought to determine was how hard the prey needs to think to survive as the complexity of the landscape increases.
Results showed that in rich savannah-like environments with a mixture of open and closed spaces, escaping predators was greatly enhanced by planning, a brain capacity that has evolved in birds and mammals.
On the other hand, there was no benefit to strategic thinking in dense jungles, open plains or water.
The reason for this is simple, says MacIver.
“In those patchy landscapes, every move you or your adversary – another human, a sabre tooth tiger – make is a move in which your position could be hidden or revealed.”
By thinking through the different options offered by a complex environment and what might happen in each possible scenario, much like in a chess game, you can work out which path is best.
“With obstacles to perception, such as opaque things like boulders or a cluster of dense bush for a visual task, suddenly a whole suite of deceptive tactics becomes useful,” MacIver says. “But you need quite some brain power to work through those tactics.”
Evolution could have then naturally selected for brains that were able to plan and envisage the future. “It could explain why we can go out for seafood, but seafood can’t go out for us.”
So why are sea mammals like dolphins and whales intelligent?
MacIver suggests these animals prove their theory, as they lived on land until 50 million years ago, and likely had developed planning ability before plunging into the sea.
As far as human brains, they nearly quadrupled in size after we split off from chimps, our closest primate ancestors. Paleoecology studies suggest we inhabited patchy landscapes that provide the greatest strategic advantage.
It’s also possible that walking on two legs helped increase our brain power in the same way, MacIver says.
“For animals that can see over the open parts of the patchy landscape, [this] means that obstacles and open areas can be strategised over so that you hide yourself while you approach your four-legged dinner, or sneak away from some big predator that is trying to approach you for dinner.”
Nowadays, it’s debatable whether superior brains are enhancing or threatening our survival.
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