Ever come across the "soul-destroying" stench of a decaying turtle or the offensive odour of vulture vomit?

If so, you may have been unlucky enough to happen upon two of the world's worst smells, according to scientists.

Biologists have taken to Twitter to reveal the worst smells they have encountered while conducting fieldwork in the natural world, but beware, the responses might make you gag.

The debate over the world's worst smell started after one Twitter user asked biologists, "What's the worst thing you've smelled in the course of your work?"

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Dozens of scientists responded with gag-worthy reports, including the stench of a weasel's anal gland secretions and the odour of rhesus macaques rotting in the sun.

But among scientists, there was one smell that is more potent than any other: the stench of a dead turtle.

"I remember a large dead turtle someone found on the road and put in the bed of their pickup in the GA summer heat. I walked by & puked," Dr David Steen, a professor of wildlife ecology at Auburn University, Alabama, said on Twitter.

And David Syzdek, a wildlife biologist from Las Vegas, agreed, posting: "Dead turtles. The odor destroyed my soul."

Dr Kathryn Wedemeyer-Strombel, a conservation scientist, also waded in, saying: "Can confirm. I did got content analysis.

"Sea turtle stomach contents dried in a drying oven is awful."

One scientist complained of the bad odour from a long-tailed weasel's anal secretions. Photo / Getty Images
One scientist complained of the bad odour from a long-tailed weasel's anal secretions. Photo / Getty Images

But the stench of a decaying sea turtle had stiff competition from a range of gag-inducing smells.

One scientist complained of the bad odour from a long-tailed weasel's anal secretions.

The animals have small anal sacks which they use to squirt out an oily liquid in self defence.

"Musk gland of a recently unfrozen long-tailed weasel on a hot day in a small museum taxidermy room. Brutal," posted a Twitter user called cj_battey, a PhD candidate in biology at the University of Washington.

Frog conservationist Jonathan Kolby, who works for the US Fish and Wildlife Service, said his job forces him to constantly confront the appalling odour of dead amphibians.

"Riding public transport with a bag full of these warm frog carcasses...I was left with plenty of legroom on the crowded train," he posted.

Jeff Higdon, a wildlife biologist from Winnipeg, Manitoba, said the worst smell he had in his career was that of a fin whale carcass that had been left to rot for six weeks.

The smell of a rotting rhesus macaque will leave a foul taste in your mouth, according to one PhD student. Photo / Getty Images
The smell of a rotting rhesus macaque will leave a foul taste in your mouth, according to one PhD student. Photo / Getty Images

He posted: "We removed the skeleton from this fin whale in 2003.

"She'd been dead about 6 weeks. Sometimes I think I can still smell it!"

And a user called Nasty Biologist (@RenoHatesMe) listed a number of foul smells she had encountered in her career.

"Bad odors in order: fresh skunk, things dead long enough to bloat, vulture vomit, feces from anything that eats fish," she posted.

And Lauren Gilhooly, a third year PhD student at Western University in Ontario, claimed the carcass of a rhesus macaque was the worst smell of all time.

In answer to the question of what smell is the worst, she said: "A decomposing rhesus macaque in the Puerto Rican heat."

The world's worst smells

1.

Decaying sea turtle

2.

Anal secretions of a weasel

3.

Dead frogs

4.

Fin whale carcasses

5.

Vulture vomit

6.

Fresh skunk

7.

Decomposing rhesus macaques