We know our pets are smart on a whole different level to us.
They know when a storm’s coming, they know when we’re sneakily trying to get into the Tim Tam packet in the middle of the night, and it seems they also know when we have our period.
Of course, cats and dogs are all over it. They've been sniffing out our periods for years - they know when things are just a little bit different with us, even if they don't have a scientific understanding of what's happening in our uterus.
In fact, cat behaviourist Mikel Delgado told the publication cats might make note of the fact we have our periods - but they really don't care.
"They have other ways they can identify us, like our voice and their sight. And for the most part, we still smell the same so our cat won't be like, 'Who is this strange new person?'"
While dogs are more likely to sniff your crotch, and embarrass you in front of your friends, they also don't have an issue with Aunty Flo coming to town.
Listen: Just glue your trap shut, he says. Post continues...
However, if you have a pet iguana - you might want to take a deep breath.
Male iguanas have been known to attack their menstruating owners. According to Dr. Beth Breitweiser, a veterinarian at All Wild Things Exotic Hospital, some males get "aggressive" when they notice different pheromone levels in their lady owners.
"Especially if you're at eye level," she told Broadly.
Dr. William Rodgers, a veterinarian in North Carolina, also notes the smell of a woman menstruating is very similar to "the pheromone of an adult female iguana during mating season".
Well, that's the most terrifying thing we've ever heard.
Let's stick to cats and dogs, OK?