'I didn't know why I felt so off about the "nice guy". Then I learnt about giraffe theory.'

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If you're a woman, you've probably had that feeling.

The one deep down in your gut where something about a man — some undefinable, ephemeral whiff of danger perhaps – alerted you to the fact that there was something 'off'.

I once worked with a man who came across as the quintessential 'nice guy'. Chose his words carefully, and came across as the kind of ally every woman wants in a workplace. 

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And yet most of my female colleagues kept him at arm's length for the same undefinable reason as I did. There was a current of 'wrong' running through every interaction that none of us were able to fully articulate, but everyone recognised. 

You've probably felt this same thing around someone. Whoever just popped into your mind is the exact type I'm talking about. 

More often than not, other men won't be able to pick up on the vibes. They'll look perplexed when you mention you don't feel comfortable around him. "What, him?" they exclaim, "He's harmless!"

It's a phenomenon I never had the words to describe, until a few weeks ago, my five-year-old told me a story about giraffes. 

Stick with me here. 

Of the endless weird facts my animal-loving girl is constantly spouting, this one stood out: the giraffe can only sleep for around 30 minutes at a time. 

It turns out that over a million years of being prey to big land predators, giraffes have evolved to only require short periods of sleep, in order to stay awake and alert to protect themselves. Their biological requirements have adjusted to meet their environment, giving the phrase 'sleeping with one eye open' a whole new meaning. And in spite of how much pity this might elicit for our long-necked African friends, it strikes me that the parallels between us might be more significant. 

Women, too, have evolved since the dawn of time to face greater risks to our safety than men. The threat of violence, both implicit and explicit, has been woven into our DNA since we were cave women. And while we've built civilisations and the iPhone and self-cleaning ovens in the meantime, that primal dynamic, sickeningly, remains.  

"Trusting our gut and listening in to our instincts as women is the most important thing we can do," psychologist Anoushka Dowling told me when I ask her to weigh in on the theory.  

"What alarm is going off inside our body, and why? And what do we need to do about it? This is often when women have to really reflect on their people-pleasing tendencies, ability to set and maintain boundaries, and their beliefs about selfishness versus selflessness."

She says another way we see 'giraffe theory' play out is the 'dark street scenario.'

"As a woman walking down a street at night, alone — if a man is to start walking behind us, we automatically register him as a threat. Even imagining the scenario, women can have a physiological response," Dowling said.

"Then, we could list about 20 things we're doing to keep ourselves safe: keys between fingers, walking fast but not running, taking ear buds out, crossing the street, talking to someone on the phone or even pretending to talk to someone on the phone, thinking of all the reasons we were stupid enough to walk down this street at this time.... which all happens in a split second.

"The guy behind us could be the nicest, sweetest, most gentle guy in the world – it doesn't matter. In that moment, he is a threat."

She also cautions that context plays a big part in these types of reactions or 'gut feelings' too. 

"I explain to clients that it is a bit like a thermostat," she said. 

"So, for some women who have experienced violence and trauma, that thermostat is sometimes a bit out – maybe a bit too hypersensitive to threat, so it needs some recalibrating. And it might not be so sensitive to threat for women who either haven't experienced violence or been exposed to it.  The more safe and secure childhood, family and life we have – the more balanced our thermostat is, and vice versa. The fact is, though, all women have the thermostat – because social conditions have created the environment for evolutionary change."

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It's precisely why the work of creating safer environments for women — and conditions for that evolutionary change to start heading in the other direction – is so vital. 

In the meantime, I'll happily listen to my little girl's endless stream of animal trivia, hoping that for a long time yet, the giraffe's sleeplessness remains just a fascinating quirk of nature to her, and not a survival strategy she eventually recognises in herself.

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