Christine Drea: You’re actually mucking about with very important social signals. All of a sudden, Betty doesn’t smell like Betty anymore. We don’t even know who she smells like. This is weird!
Dr. Christine Drea is an animal behaviorist at Duke University. She’s talking about her study – the first of its kind – that analyzed the impact of a form of birth control on the chemicals that make up an animal’s unique scent. In this case, the animals were lemurs – a type of primate related to monkeys and apes. Drea’s study showed that birth control dramatically altered the way the lemurs smell.
Christine Drea: It’s exactly like a fingerprint. It’s called a scent signature. We have these in the pattern of our skin. We have it in our voice. We have it in our scent.
Female lemurs in Drea’s study were given the contraceptive DepoProvera.
Christine Drea: It not only affected the chemical signals of fertility but it also obliterated the signals of an animals individual identity, your scent signature that says “you are uniquely you.” It’s their kinship. It’s their genetic quality. All of that gets either completely lost, or scrambled or subdued in some way.
Drea suggested that when an animal’s scent is “off”, confusion in mate selection can result. Changing an animal’s scent might even prevent members of a group from getting along, she said. She added that scent-based research is so new, it’s impossible to generalize about how birth control – or any other drug – might be affecting humans or another animal species.
In this particular experiment, Dr. Drea worked with Depo Provera (medroxyprogesterone acetate), a drug very similar to progesterone, a hormone normally produced by the ovaries every month as part of the menstrual cycle. Drea explained that her team measured the change in chemicals in lemurs given the drug via fluids obtained from them. (All the samples were non-obtrusively obtained, she noted.)
Christine Drea: If you take a sample from a normal female, she will show something around the vicinity of 300 different chemicals in her secretions. Contracepted females lost some of the normal complexity of the scent signal. There were some chemicals they lost completely. They also started expressing compounds before that we had never seen expressed in an intact female. They were somehow manufacturing odors that were different from what they normally manufacture
In other words, female lemurs given contraceptives didn’t smell as they normally do. What’s more, Drea said, the new scent profile of the female lemurs on contraceptives tended to be similar. That is, these various lemurs smelled (too much) like each other. She said that the males noticed this change in scent, and appeared not to like it very much.
Christine Drea: Males definitely spend much more time investigating, sniffing, licking the odors of females when they’re intact than when they’re contracepted. In other words, they prefer the odor of (non-contracepted) females.
Soon after my wife and I started dating she started taking birth control pills. I noted a difference rather quickly in her scent. I assumed it was an individual anomaly that would pass, I ignored it for awhile but then I couldn’t get over it. Finally, one day I told her and she stopped taking the pills a few weeks later the unusual scent was gone and everything went back to normal. Somehow I always thought I was crazy but not know.
Walter, thanks so much for your comment! You are not crazy.
:)
Beth
That’s really interesting. I’ve always felt like we underestimate the importance of our sense of smell.
hey, thanks LP!
beth
Perhaps we should leave some things in nature alone, although this is very amazing and interesting information! Thanks for the insights into this!
Thanks for your comment, Vickie.
We humans are, after all, just animals. We communicate information through scent. What does it mean when that information – and scent – gets mixed-up?
I’m looking forward to seeing more studies on this.
Animal testing for human medication is atrocious. How about just a study on humans. Anyway..as interesting as this is, it’s still an injustice to force medication on a participant that is unwilling to consent and whom it benefits in no way at all. Why don’t they just do it to our Military people instead..seeing as that’s part of the contract they sign.
Stephanie, I hear you.
I talked to Dr. Drea about this *extensively*.
First, it’s common for lab animals to be given birth control, so they don’t reproduce during the course of experiment. Drea just happened to document the before/after effects.
Second, Drea’s lemurs are treated very well. I personally got the impression they are loved and cared for.
That was important to me, and it seems important to you.
As for why this experiment was done on lemurs and not on humans, that’s something I can’t entirely account for.
I’ll see if Dr. Drea can address the question on this website.
Yours truly,
Beth
To address Stephanie’s comment, Beth is correct. Dr. Drea’s research was not at all an experiment in testing drugs on animals. It was opportunistic. In fact, as Beth said, contraceptives are common in zoos throughout the world. This is actually to help maintain genetic variability within captive populations of animals. By preventing indiscriminate breeding, scientists/researchers/management teams are helping to prevent inbreeding depression, as well as helping to prevent overpopulation of animals that ultimately cannot (in most cases) be released in to the wild. There are actually teams of scientists who work together to monitor and manage captive populations for these reasons. While it’s unfortunate that we need to have captive populations, in cases when we do, it is in *everyone’s* best interest to be responsible with their management. This includes contraception.
…and Dr. Drea’s study is really interesting. Really makes us think about how we’re messing with our own sexual selection processes by artificially managing our own reproductive biology.