Men and women travelled on the canoes together. Colonisation of islands is difficult if you only have guys eh?

Certainly oral legend of the Māori is mixed crews e.g. “According to some accounts, Horouta was the first waka [=canoe] to make landfall in this region. The captain of the Horouta was Pawa, the navigator was Kiwa. It carried a large crew of men, women and children – as well as a dog named Whakao, belonging to Pawa.”

Having women and children on board isn't necessarily incompatible with the idea that the drive for the insanely risky exploration was fueled by testosterone.

So these days with so many artificial ingredients and ultra processed foods and sedentary habits leading to decreased testosterone these journeys might not have taken place had they had our modern diets [and as child comment adds, lifestyle]?

I'm far from a scientist, but in my observations and reading, lifestyle has a far bigger impact than diet. Hard work boosts testosterone, there was even a study done showing how much it was boosted during chopping wood, for example. Modern folks are sedentary and often overweight, both of which contribute to lower testosterone, likely moreso than diet ever could.

Men today are observably less 'manly' than in the past. But we seem to try to find someone or something to blame other than ourselves.

It seems that phthalates (plastic softeners) are also reducing testosterone.

https://doi.org/10.1093/humrep/dev225

A bit of A, a bit of B.

The modern diet is also very processed and refined. White bread and white rice were not available for mass consumption until industrialization.

Japan's navy solved an issue with beriberi disease after changing the rations from white rice to barley. https://www.atlasobscura.com/articles/rice-disease-mystery-e...

Maybe also selection pressure (which has largely been removed). The men _who_survived_ were more manly in the past.

Perhaps, but I think we can drill down a bit further.

Many third world countries have foods much, much more processed than we do in USA, yet they don't exhibit such effects generally.

My own family is a huge old Irish/German conglomeration...I have 12 uncles and aunts. There's very clear demarcation of millenials vs the older ones, and especially those raised in a rural setting vs urban.

I'd honestly like to see studies of how many, let's say 'metro' men spent summers bucking hay or stripping tobacco as a kid. I did, but I'm clearly less grizzled than my cousins who did such work year round as a kid.

And I don't mean any of this to be insulting. I'm way less manly than my own father, and a millennial who spent childhood glued to screens.

Why do you describe something like bucking hay or stripling tabacco as 'manly' when it was a common activity for women as well in traditional society?

I don't. I just mentioned them because they are very common labor intensive summer jobs where I grew up. Replace with whatever your local variant would be.

Problem is that unless you've actually got symptoms of low testosterone, it's not a big issue. Low T being the cause of men's problems today is a myth.