Humans living on Mars could become space cannibals.
Scientists have warned that humans may be forced to eat each other if farming plans for the red planet fail to materialise.
Elon Musk is determined to colonise Mars with SpaceX and hopes to start running flights to the planet by 2026 but experts fear it may not be the paradise that is hoped for.
Charles Cockell, professor of astrobiology at Edinburgh University, said: "Even with the best technology, isolated human communities can degenerate very quickly.
"If things start going wrong and the plant growth module breaks down, they are going to eat each other if there is no other way to survive."
Boffins have also warned that flights to Mars could age people faster than on Earth, with the first study into the senescence phenomenon due to take place next month.
Cellular aging expert Dr. James Kirkland said: "This flight will give us an idea of whether routine spaceflight is associated with cell senescence."