Five strange but true science facts

A new Australian study has shown how culling sharks disrupts the ocean's natural food chain and ultimately leads to the release of carbon from the seafloor. Photo / Getty

How sharks help fight climate change

Amid all the blood and gore in shark horror movies like Jaws, Deep Blue Sea and Sharknado, there's unsurprisingly nothing in there about how the big predators actually help fight the effects of climate change.

A new Australian study has shown how culling sharks and other large marine predators disrupts the ocean's natural food chain and ultimately leads to the release of carbon from the seafloor.

With fewer sharks in the food chain, the predator's food sources, such as sea turtles, flourish.

The turtles in turn feast on seagrasses, which store carbon within sediment. The carbon is unlocked and released into the earth's atmosphere helping accelerate climate change.

Beauty really is in the eye of the beholder

Who we find attractive isn't determined by some complex genetic construct, but simply by our own personal experiences.

That's the upshot of a Current Biology study that surveyed hundreds of genetically even identical twins to pinpoint whether our DNA makes any contribution to why we each find certain faces better looking than others.

The researchers found that experience was most important in deciding, and that those experiences were highly specific to an individual.

And it wasn't just about the school you went to, how much your parents made, or who lived next door - that pretty face you see is more relevant to ones you've seen in the media, your unique social interactions and perhaps even the face of your first boyfriend or girlfriend.

Teens' fishy hunch leads to new discovery

Students tried to work out how the kokopu had insects in their bellies. Photo / Christine McKay

A fishy observation has landed two Auckland teens in the New Zealand Journal of Zoology.

On a science field trip to Le Roy's Bush this year, Northcote College students Ben Whittington and Zac Martin tried to work out how it was the nocturnal freshwater banded kokopu had insects in their bellies that didn't match up with collected stream samples.

The answer came as they noticed the fish jumping out of the water to snatch at items on the bank.

So the students planted wax moth larvae on the side of the pool and confirmed something that has never been recorded for the species - that kokopu like to eat on the hop.

The lowdown on snogging

It takes only 10 seconds of kissing to transfer as many as 80 million bacteria. Photo / Getty

Consider this next time you're having a snog at the movies - it takes only 10 seconds of kissing to transfer as many as 80 million bacteria.

Even more unsettling in a new study in the journal Microbiome is that partners who kiss each other at least nine times a day share similar communities of oral bacteria.

Dutch researchers studied the kissing behaviour of 21 couples, who were asked to record their average "intimate kiss frequency" before swap samples were taken to figure out the composition of their oral microbiota on the tongue and in their saliva.

Our bodies are a universe of more than 100 trillion microorganisms essential for the digestion of food, synthesising nutrients, and preventing disease - and it's shaped by genetics, diet, and age.

With the mouth playing host to more than 700 varieties of bacteria, this new study shows oral microbiota also appear to be influenced by those closest to us.

Why does that comet look like a duck?

If you've ever glanced at the comet 67P/Churyumov-Gerasimenko and wondered why it looks like a rubber duck, scientists have the answer.

The comet, now part of history after the European Space Agency managed to land on it last year, is made up of a larger lobe and a smaller lobe, separated by a thin "neck" region that gives it an odd, duck-like shape.

Now, a new study in the journal Nature has confirmed suspicions that the comet is actually two objects that at some point smacked into each other.

The similarity and composition of the two chunks ultimately led them to conclude that the 2km-sized cometesimals were formed by similar processes before they merged, at some point in the early solar system.