I just read an article about ancient bacteria surviving nearly a million years in harsh, frozen conditions. The arguments have suggested that Mars could have some sort of life. Unlike us, they can stay alive in a very long run. If it can survive for a long time on our planet, there is a probability that it could survive on Mars. The bacteria survived by eating nutrients like nitrogen and phosphate that are found in the permafrost. Do the bacteria enjoy living in the environment that is much colder with more stable temperatures like Mars? For further reading, click on the link below.
Ancient bacteria could point to life on Mars: study