Land animals are, on the whole, smarter than marine creatures and scientists now believe this is because complex landscapes sped up the evolution of intelligence.
Animals first left the seas and colonised land around 385million years ago but their brains were far more primitive than modern-day species.
This, scientists say, is because the simplicity of the ocean’s landscape does not require animals to have to plan ahead and predict what may happen in the future.
When an animal hunts another in the water, the contest is purely about speed, with few other factors playing a part.
However, on land, there are obstacles such as rocks, trees and bushes, which make the environment trickier to navigate in a hunt.
It is this which ‘poured jet fuel on brain evolution’ of land animals, scientists believe, as animals could gain a survival edge by planning and trying to predict future events.
It turned survival into a chess match, with the complex environment and its various features acting as the board on which the animals duelled.
Pictured, the Okavango Delta. its patchy landscape is a good example of the ‘Goldilocks landscape’ where the ability to plan results in a huge survival payoff, the researchers say
Researchers found the perfect environment for nurturing cognitive development is one that is not too empty and not cluttered, such as a Savannah.
This was dubbed the Goldilocks-zone of terrain in which being able to plan and devise strategies is a real benefit and therefore the animals evolved to be smarter.
In simple landscapes like open ground or packed landscapes like dense jungle, there was no advantage. This was similar to what was seen in the seas.
All of Earth’s most intelligent animals are land-dwelling creatures, including humans, chimps and elephants, with the notable exception of dolphins and whales.
However, the researchers say these marine mammals actually evolved their intellect on land before moving to a water-based existence around 50 million years ago.
‘All animals – on land or in water – had the same amount of time to evolve, so why do land animals have most of the smarts?’ says Professor Malcolm MacIver, who led the study from Northwestern University.
‘Our work shows that it’s not just about what’s in the head but also about what’s in the environment.’
The presence of features on land makes it more complex than the blank abyss of the sea, and this meant animals that evolved the ability to plan and develop hunting strategies were at an advantage. This separated land animals from sea creatures
Researchers found the perfect environment for nurturing cognitive development is one that is not too empty and not cluttered. But in simple landscapes, like open ground, or packed landscapes, like dense jungle, there was no advantage
Chimps smack their lips together to talk to each other at almost exactly the same speed as chattering humans
Chimpanzees smack their lips together at almost the same speed as chattering humans, a study has revealed.
Primatologists found the striking similarity after watching videos of the African apes during grooming sessions.
The results suggest human ancestors had at least some of the tools for language as early as five million years ago – when the lineages split.
Primatologists from the universities of Warwick and St Andrews watched clips of our closest relative at Edinburgh and Leipzig zoo.
They compared this to two wild troops in Uganda, finding they could move their lips two to four times a second.
This closely matches humans, who are able to move their lips two to seven times a second.
Previous research from the team found that eyesight was a factor in helping animals become smarter.
In water, eyesight is restricted and often poorly developed, with little to look at and the water physically limiting how far an animal can see.
When life moved to the land, this restriction was lifted. But the scientists found improvements to eyesight was not enough to explain the boost to intelligence.
Instead, something else was needed to nourish the brain.
‘We speculated that moving onto land poured jet fuel on the evolution of the brain as it may have advantaged the hardest cognitive operation there is: Envisioning the future,’ Professor MacIver said.
‘It could explain why we can go out for seafood, but seafood can’t go out for us.’
The team used computer simulations to replicate what happens when animals with varying levels of smarts are put in different situations.
Professor MacIver said says: ‘In the open aquatic environments, you just need to run in the opposite direction and hope for the best.
‘While in the highly packed environments, there are only a few paths to take, and you are not able to strategise because you can’t see far.
‘In these environments, we found that planning does not improve your chances of survival.
”With patchy landscapes, there is an interplay of transparent and opaque regions of space and long-range vision, which means that your movement can hide or reveal your presence to an adversary.
‘Terra firma becomes a chess board. With every movement, you have a chance to unfurl a strategy.’
The research is available in the journal Nature Communications.