That picture has got you wanting to yawn already, hasn’t it? Go ahead, breathe it in, really enjoy it. We’ve got some news for you about that yawn.

It turns out a longer yawn indicates a larger brain. Well, between mammals at least.

Baby yawning
Yawning starts early – it’s even been shown that babies yawn in the womb (Thinkstock)

Scientists from the University of New York at Oneonta examined footage of 29 different yawning mammals, including humans.

Their findings showed that mammals with smaller brains and a lower number of neurons in their brain cortex, such as mice, foxes and hedgehogs, had significantly shorter yawns than those with larger brains and a higher number of neurons, such as primates and elephants.

Seal pup watches mother yawn
At least cover your mouth, mum (Owen Humphreys/PA)

The study, published in The Royal Society Biology Letters journal, found in particular that brain weight and relative brain size had the strongest correlation with yawn duration.

For example, on average humans had the longest yawn, at over six seconds, while elephant yawns were roughly six seconds. In contrast, a rabbit yawn was on average 1.5 seconds, while the shortest, a mouse yawn, was less than a second.

Lion yawning
If you haven’t yawned by now you’re a real trooper (Rajanish Kakade/AP)

Scientists are yet to agree the reasoning behind why animals yawn, but it has often been cited as a means to cool the brain down and increase blood flow to the brain. The researchers from this study say their findings lend support to this hypothesis.

They said the findings “highlight the importance of measuring yawn duration in future research”. If this means trawling through more videos of animals yawning like these, we certainly aren’t complaining …

The hedgehog. Too much.