Yes, according to animal behaviorists: pets are likely to sense pregnancy.  Animals (Cats and dogs) can detect changes in smell even before a pregnancy test does because their sense of smell is extremely sophisticated.  Animals are not the only human condition that feels changes before humans do, especially during pregnancy. Change in smell-A woman's body chemistry changes when she becomes pregnant. Consequently, her distinct odor (something her dog knew intimately) may change.  Therefore, it is only natural that dogs will notice the changes in the owner's mood or behavior during pregnancy. Many pregnant women report that their dog becomes more affectionate and protective during pregnancy, according to Rachel Barrack, DVM, owner of Animal Acupuncture in New York City.  She explains that it's likely due to the scent, your hormones, and changes in your mood.