Mammals, birds, and other life survived the asteroid impact 66 million years ago, whereas mammals cannot survive unprotected on Mars's surface.

“66 million years ago was a nicer day for life on earth than any day on mars in the last you know two or three billion years at least and we know that because mammals survived and birds survived and all sorts of life survived that day whereas there's no mammal that are now that could survive unprotected on the surface of mars um”