Sponge-like creatures could be lurking beneath the surface of Mars, according to new research.
Salty subterranean lakes on the Red Planet are capable of providing enough oxygen to support even simple animals, scientists believe.
It has long believed there is not enough air on Mars to support life.
But a computer model developed by a US team suggests the planet's briny underground lakes is composed of salt and water.
And they are probably able to store up enough oxygen to allow alien life to flourish.
The new study, published in Nature Geoscience, believes these areas are especially concentrated in the poles of the planet.
Dr. Vlada Stamenkovic said the briny water will also be abundant in calcium and magnesium which boost bone and metabolism.
But places "with sufficient oxygen available for aerobic microbes to breathe" may be all over the Red Planet.
He added: "Moreover, about 6.5 percent of the total Martian surface area could support far higher dissolved oxygen concentrations, enabling aerobic oases sufficient to sustain the respiration demands of more complex multicellular organisms such as sponges."
It is thought that if life existed in these watery havens then they could resemble life in neighboring Earth
Dr. Stamenkovic, a planetary scientist at the California Institute of Technology in Pasadena, said: "Due to the scarcity of oxygen in the modern Martian atmosphere, Mars has been assumed to be incapable of producing environments with sufficiently large concentrations to support aerobic respiration.
"Here, we present a thermodynamic framework for the solubility of oxygen in brines under Martian near-surface conditions."
Dr. Stamenkovic said little attention has been given to the role of oxygen on Mars, due to its scarcity.
But geochemical evidence from Martian meteorites suggests it once had large amounts thanks to its warm atmosphere and liquid oceans which played a role in the weathering of its crust.
He said: "Aqueous environments, in the form of brines, can exist today at, and especially below, the surface despite the thin atmosphere and overall cold climate."
Recent evidence demonstrates hydrated magnesium and calcium salts at various locations on the surface and shallow subsurface.
This suggests there could be oxygen "comparable to the concentrations in Earth's oceans today."
Dr. Stamenkovic said: "Thus, in principle, Mars could offer a wide range of near-surface environments with enough dissolved oxygen for aerobic respiration like that seen in diverse groups of terrestrial microorganisms."
Searching alien life is something which a growing number of groups believe NASA should be doing more regularly.
For example, the National Academy of Sciences (NAS) released a report last week that calls for NASA to make the search for extraterrestrial life an "integral part of its missions."
This story originally appeared in The Sun.