Scientists Seldom Test On Female Lab Rats Because Females Have Hormonal Cycles


Jul 2, 2019


Ever since Victorian quacks decreed she-rats too complex, the ratio between male and female rats used for experimentation has been 5.5 to 1.

In today’s episode of “I’m Begging You … Consider Any Other Gender,” apparently male rats have held a monopoly over being experimentation fodder. Scientists have only recently rubbished the notion that female rats can’t be experimented upon due to female cycle-related hormonal surges. Though scientists previously knew that male rats also undergo hormonal surges due to spikes in testosterone, they’ve still continued to ignore female rats because…crazy women, am I right, lads?

Male rats were used as the standard because scientists believed that hormone changes throughout the female cycle caused female rats to react differently to the same stimuli — making them unpredictable and providing scientists with variable results during repeated experiments. Many scientists also believed that female rats displayed more varied behaviors among themselves, even when at the same point in their cycles, whereas the behavior of male rats was believed to be more uniform. Old school scientists believed that studying the male member of a species was the best way to understand the most basic functions and behaviors of that species.

However, the latter is untrue. And the former, while accurate, shouldn’t be a deterrent to testing, because while female rats are variable across days and weeks, testosterone spikes make male rats variable by the hour. Yet, ever since Victorian quacks decreed she-rats too complex, due to the existence of reproductive organs that weren’t giant dicks, the ratio between male and female rats used for experimentation has been 5.5 to 1, according to a 2011 study in the journal Neuroscience & Biobehavioral Reviews. The ratriarchy is real folks!

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Female lab rats experience hormonal fluctuations for four to five days during their reproductive cycle, often self-administering cocaine and having more anxiety during that period (and no, this isn’t the protagonist of a new Netflix comedy). However, their male rodent counterparts (dudents?) exhibit variable ranges of testosterone on a much more frequent basis; whenever they are bullying other rats, or being around a female rat, their hormone spikes make them act more aggressively. But these spikes and this behavior have been widely considered more normal and predictable than female — proving yet again, that toxic machismo transcends species.

Rebecca Shansky, a neuroscientist, took out the time and energy to educate everyone about the obvious in an article about unconscious gender bias in clinical experimentation for the journal Science. She told The Guardian that, “People like to think they’re being objective and uninfluenced by stereotypes, but there are some unconscious biases that have been applied to how we think about using female animals as research subjects that should be looked at by scientists.”

Irving Zucker, a behavioral neuroendocrinologist who also had to expend precious time and energy to state the obvious, told Science News that, “When you compare males and females side by side, males are more variable over the course of the day, and females are more variable across days.” 

In conclusion, we really do live in a society. Here we are, in 2019, looking square in the face the idea that people whose literal job is to research animal anatomy, physiology, diseases, drug reactions, etc., legit spent decades since the Victorian era just … not really investigating female bodies. Scientists just looked at a whole female rat body with a completely different set of reproductive organs and hormones to explore and just went, ‘Nah, she’s probably PMSing,’ while completely dismissing male rats, doing the rat version of beating each other up, as normal. The more dumbfounding bit is that nobody’s particularly surprised, considering how often unconcerned men (and sometimes women) of science become when girl problems and girl pains threaten to waste their time. While science has treated women better than the more archaic stuff out there, why must we — in 2019 — have to remain pissed that treatment and research are coded to one type of human body when there is more than one body type?

However, progress is happening. Federally funded scientists in Canada and the U.S.A.’s National Institute of Health are expected to use both male and female species in their research, following a 2016 policy update. There is still hope for global reforms in research regarding testing and experimentation on all genders of any species.

Till then, congratulations to female rats for torture and death cage equality!


Written By Aditi Murti

Aditi Murti is a culture writer at The Swaddle. Previously, she worked as a freelance journalist focused on gender and cities. Find her on social media @aditimurti.


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