Intelligent life more likely to evolve in oceans

A new astrobiology paper argues that technology-based intelligence is more likely to evolve in oceans than on land.
Paul Ratner
Why didn't dolphins develop tools?
Why didn't dolphins develop tools?

Credit: Claudia14 / Pixabay

  • A new study looks at whether technology-based intelligent life was more likely to emerge in oceans or on land.
  • The researchers found oceans were more likely to support such intelligence.
  • But being on land may offer factors that made it easier for intelligent life to develop.

The nature and qualities of intelligence are frequently debated topics. Are humans the only intelligent species out there? Are we even the most intelligent on Earth? We certainly like to think so. While animals like dolphins, ravens, and elephants may be ranked high on the intelligence scale (judged from the human perspective), we don’t see them setting up complex societies (as far as we know).

In astrobiology, this question is an important one, especially as humans look to the stars. Where will we have the best chance of finding other intelligent life in the Universe — on land or in water?

A new study from a team of astrobiologists adds an interesting twist to this debate. According to Florida Tech assistant professor of Aerospace, Physics, and Space Sciences Manasvi Lingam, technology-based intelligence is more likely to evolve in oceans rather than on land. Yet, how does that square with our own reality as a land-based species?

The paper by Lingam and researchers from the University of Texas and Università di Roma relies on Bayesian analysis to look at the probability of intelligent species emerging in land-based or ocean-based habitats.

The researchers found that if all factors remained equal, the ocean-based habitats would be more conducive to the emergence of technological species because of the sheer variety of ocean habitat. Oceans, after all, cover around 71 percent of the Earth’s surface. 

Developing tech in water

The researchers focused on the development of tools as a measure of intelligence.

They concluded that one reason why such intelligence may not be as widespread in oceans as might be expected is that developing tools and complex technology in water might be more complicated than on land.

As Manasvi Lingam explained in a press release,”maybe it takes a really long time for life to emerge in the ocean because of various biophysical reasons such as the sensory capacities in land versus water.”

He added that while water is likely where life began, the aquatic environment can actually impede the development of technology. “Another possibility is, due to some set of factors (e.g., energy sources), maybe oceans are not as habitable for intelligent life as we think they ought to be,” he shared.

For the research, the team used data from life on Earth to account for different species of intelligent life, from primates to cephalopods (think octopuses) and cetaceans (like dolphins). They also utilized mathematical and physics models (particularly Bayesian probability theory) to determine the likelihood of intelligence emerging in water versus on land.

Further data from telescope observations, field studies of animal behavior, and the role of oxygen in the evolution of complex life were also explored.

Intelligent life more likely to evolve in oceans
The probability of intelligent life emerging on land vs ocean

Deeper insights

Interesting Engineering (IE) reached out to Manasvi Lingam for a closer look at the paper. 

The following exchange has been lightly edited for clarity and flow.

Interesting Engineering: What constitutes an intelligent species in the context of your research?

Manasvi Lingam: Thank you for raising this question. The word "intelligence" is rather nebulous, owing to which we pivot to putative species that belong to a similar category (this specification is also important for the probabilistic analysis) as humans, namely, those with intensive and extensive technology. Hence, we use the phrase "technological intelligence" to convey this point.

IE: Could we be misunderstanding the extent of the intelligence of ocean-based species? In other words, how do we know humans are more intelligent?

I do not believe that humans are "more intelligent" since this aspect is hard to quantify and establish. It does seem, however, that humans are more adept than any other species at constructing technology (see point #1 above). Oceanic species display many signatures of high intelligence such as theory of mind, complex communication, and some basic tool usage. I have reviewed all of these facets in Chapter 7 of my 1100-page book entitled "Life in the Cosmos".

IE: As your analysis shows a potential preference for technology-based intelligence to have evolved in oceans, what explains the emergence of humans on land?

The potential preference comes merely from the fact that there seem to be so many more water worlds than those with land on them. In other words, if all other factors are held equal (and this is key), then technology-based intelligence would be more likely to evolve in oceans. However, we cannot assume that "all other factors are held equal", and we discuss avenues by which land may be favored over oceans as a much more conducive habitat for the emergence of technological intelligence (see point #4 below).

IE: What makes ocean-based habitats more preferable for the emergence of technology-based intelligent species?

As noted in point #3 above, ocean-based habitats are more plentiful, and this may seem to rule in their favor. However, if one starts to look at the properties of oceans and land, the former seems to have some physical characteristics that are more conducive to technological intelligence. Life on land needs to expend less energy to move around, such life can see farther (vision), such life can harness fire, etc. compared to ocean-based life.

Read the full study “A Bayesian Analysis of Technological Intelligence in Land and Oceans” in The Astrophysical Journal.


Current research indicates that (sub)surface ocean worlds essentially devoid of subaerial landmasses (e.g., continents) are common in the Milky Way and that these worlds could host habitable conditions, thence raising the possibility that life and technological intelligence (TI) may arise in such aquatic settings. It is known, however, that TI on Earth (i.e., humans) arose on land. Motivated by these considerations, we present a Bayesian framework to assess the prospects for the emergence of TIs in land- and ocean-based habitats (LBHs and OBHs). If all factors are equally conducive for TIs to arise in LBHs and OBHs, we demonstrate that the evolution of TIs in LBHs (which includes humans) might have very low odds of roughly 1 in 103 to 1 in 104, thus outwardly contradicting the Copernican principle. Hence, we elucidate three avenues whereby the Copernican principle can be preserved: (i) the emergence rate of TIs is much lower in OBHs, (ii) the habitability interval for TIs is much shorter in OBHs, and (iii) only a small fraction of worlds with OBHs comprise appropriate conditions for effectuating TIs. We also briefly discuss methods for empirically falsifying our predictions and comment on the feasibility of supporting TIs in aerial environments.

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