Thanks A Lot, Evolution

I read that humans are the only animals known to get morning sickness. Scientists don't know why that is. They can hypothesize reasons for why morning sickness might be beneficial to a pregnant lady and her baby, but they're not so sure as to why only humans get morning sickness.

I wonder when that started, in terms of the evolutionary process. Was evolution like, "Hold on. These cave ladies are eating waaaaaaay too much rotten food. It's time to make this species adverse to some of the crap they eat when they're pregnant, or there's going to be serious trouble"?

I'm so glad I'm done with the worst part of my morning sickness. Yay for the second trimester!