Insects need oxygen. Indeed just about all multi-cellular animal life does. There is almost no oxygen in the Mars atmosphere although the surface rocks are highly oxygenated.
So - more likely to be plants or lichens or microbes of some sort. Though there are a few multicellular creatures that are able to manage without oxygen. And who knows, maybe Mars has oxygen rich water deep underground or some such, or oxygen rich micro-habitats on the surface.
I think not impossible that we do find multicellular animal life on Mars. Especially as it doesn't have to resemble Earth life, maybe some multicellular creature that is not related to anything we have here. And we already have multicellular anaerobes on Earth.
However the other problem with Mars is that it is extremely arid. Like our driest deserts, and more so. And so arid, that even if there was liquid water on the surface, over most of the surface the water would boil instantly, because the air is so thin, the boiling point gets reduced to below the melting point of ice. In the very deepest places it could survive briefly but soon dry out.
So, life as we know it needs liquid water. There may be micro-habitats on the surface however. Thin patches of damp salt - on the interface between salt and ice for instance. If these habitats exist, they would be invisible from orbit. Then the enigmatic dark seasonal flows, and some other features - most of the features are surely caused by dry ice or wind - but some of them - because of their appearance, location, when they form in the year, where they form - the only likely hypothesis at the moment is, some kind of feature that is caused at least indirectly by melting ice. Because they occur for instance,the warm seasonal flows, on sun facing slopes, seasonally, when the temperature locally goes above 0C.
So - if these habitats do exist, then they could, conceivably have not just microbes, but also higher lifeforms also - some form of plant / lichen, maybe some tiny creatures. But we wouldn't see them from orbit. I don't know what the chance of that is though.
The thing is that on Earth places as dry as the deserts of Mars - like the very heart of the Atacama desert - they tend to be inhabited only by microbes. So maybe that's the same story on Mars? Hard to say for sure though. Life there could have evolved differently from Earth of course.
There's also the possibility of deep life. On Earth life is now found kilometers below the surface. Mars has, probably, a hydrosphere a few kms below the surface where it gets warm enough for liquid water. Again there could be life there, and just possibly, simple multi-cellular life also, as multicellular life has been found deep underground on the Earth.
It depends also on life on Mars evolving multicellularity. So - if for some reason it never got to that stage, even a planet with habitats for insects and tiny multi-cellular creatures might only have microbes. At some point in the past the Earth, a bit over 500 million years ago, would have had only single cell life, almost entirely. So Mars could be in that same state right now, even if it has habitats for multi-cellular life might just have never evolved it.
With the recent Curiosity discovery of spikes in methane on Mars, maybe there will be more interest in such ideas also.
As for sending them to Mars, then - the very last thing most scientists would want to do right now is to introduce life to Mars. Because if you do that, how can you ever know what it was like before you did that? The detection of life on Mars, which could be one of the biggest discoveries in modern science, might turn out to be the biggest anticlimax in modern science instead - detection of life you brought there yourself.
So - more likely to be plants or lichens or microbes of some sort. Though there are a few multicellular creatures that are able to manage without oxygen. And who knows, maybe Mars has oxygen rich water deep underground or some such, or oxygen rich micro-habitats on the surface.
I think not impossible that we do find multicellular animal life on Mars. Especially as it doesn't have to resemble Earth life, maybe some multicellular creature that is not related to anything we have here. And we already have multicellular anaerobes on Earth.
However the other problem with Mars is that it is extremely arid. Like our driest deserts, and more so. And so arid, that even if there was liquid water on the surface, over most of the surface the water would boil instantly, because the air is so thin, the boiling point gets reduced to below the melting point of ice. In the very deepest places it could survive briefly but soon dry out.
So, life as we know it needs liquid water. There may be micro-habitats on the surface however. Thin patches of damp salt - on the interface between salt and ice for instance. If these habitats exist, they would be invisible from orbit. Then the enigmatic dark seasonal flows, and some other features - most of the features are surely caused by dry ice or wind - but some of them - because of their appearance, location, when they form in the year, where they form - the only likely hypothesis at the moment is, some kind of feature that is caused at least indirectly by melting ice. Because they occur for instance,the warm seasonal flows, on sun facing slopes, seasonally, when the temperature locally goes above 0C.
So - if these habitats do exist, then they could, conceivably have not just microbes, but also higher lifeforms also - some form of plant / lichen, maybe some tiny creatures. But we wouldn't see them from orbit. I don't know what the chance of that is though.
The thing is that on Earth places as dry as the deserts of Mars - like the very heart of the Atacama desert - they tend to be inhabited only by microbes. So maybe that's the same story on Mars? Hard to say for sure though. Life there could have evolved differently from Earth of course.
There's also the possibility of deep life. On Earth life is now found kilometers below the surface. Mars has, probably, a hydrosphere a few kms below the surface where it gets warm enough for liquid water. Again there could be life there, and just possibly, simple multi-cellular life also, as multicellular life has been found deep underground on the Earth.
It depends also on life on Mars evolving multicellularity. So - if for some reason it never got to that stage, even a planet with habitats for insects and tiny multi-cellular creatures might only have microbes. At some point in the past the Earth, a bit over 500 million years ago, would have had only single cell life, almost entirely. So Mars could be in that same state right now, even if it has habitats for multi-cellular life might just have never evolved it.
With the recent Curiosity discovery of spikes in methane on Mars, maybe there will be more interest in such ideas also.
As for sending them to Mars, then - the very last thing most scientists would want to do right now is to introduce life to Mars. Because if you do that, how can you ever know what it was like before you did that? The detection of life on Mars, which could be one of the biggest discoveries in modern science, might turn out to be the biggest anticlimax in modern science instead - detection of life you brought there yourself.
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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