Not long after, he decided to take a look at his ejaculate – definitely not an accident – and discovered tiny, jiggling creatures with tails, which he called “little animals”.
As scientists looked back and forth from top to bottom in their microscopes over the centuries, there was no doubt what their eyes saw and captured on film: sperm swim by moving their tails back and forth.
Why shouldn’t we trust our eyes? Science has believed in that ever since.
A “sperm deception”
It turned out that our eyes were wrong.
“If you want to see the real beating of the tail, you have to move with the sperm and rotate with the sperm. So it’s almost like you have to make a (camera) really tiny and stick it to the head of the sperm.” Said Gadelha.
Gadelha’s co-authors, Gabriel Corkidi and Alberto Darszon of the Universidad Nacional Autonoma de Mexico, developed a way to do this. Using state-of-the-art tools, including a super high-speed camera that can take over 55,000 frames per second, the researchers were able to see that the movement from side to side was actually an optical illusion.
In reality, the sperm’s tail whips only on one side.
This one-sided stroke should cause the sperm to swim in an eternal circle, said Gadelha. But no, sperm was smarter than that.
“Human sperm has found out whether it rolls while swimming, much like playful otters corking through water. Their one-sided stroke would balance out and they would swim forward,” said Gadelha, a fertility math expert.
“The rotation of the sperm is very important. It allows the sperm to regain symmetry and actually go straight,” he said.
The results were a real surprise, Gadelha said, and the team spent almost two years repeating the experiment and checking the math. The results lasted: just like the earth It turned out that sperm are not flat and don’t really swim like snakes or eels.
Why is that so important?
“The rolling motion might hide some subtle aspects about the health of this sperm or how well it can get around,” said Gadelha.
“These are all very hypothetical questions. We hope that more scientists and fertility experts are interested in them and ask: ‘OK, how does this affect infertility?'”
Gadelha is humble in how it feels to reverse over 300 years of scientific beliefs.
“Oh god, I always have a deep feeling that I’m always wrong,” he said.
“Who knows what we’ll find next? This is a measurement taken by an instrument that has its limits. We’re right at this point, but we could be wrong about the progress of science. And hopefully it will it’s something very exciting that we’re going to do. ” learn in the next few years. “