Animals Leave a Trace — Even in the Air
Imagine walking through a zoo and being able to tell exactly which animals live there — not by seeing them, but by sampling the air. Sounds like science fiction, right? Well, it’s not. Two fascinating studies have shown that animals leave tiny traces of their DNA in the air, and scientists can now use that to detect them.
Every animal sheds DNA into its surroundings. It might come from skin, hair, saliva, urine, or even poop. This DNA ends up in the environment, and researchers have already been using it to learn a lot from water and soil. For example, they’ve used it to track fish, detect diseases in frogs, and even investigate whether the Loch Ness Monster might just be a big eel.
But what about the air? Could it be possible to catch DNA floating around and use it to figure out which animals are nearby?
Turns out, yes!
Two different research teams went to zoos to test this idea. One team, led by Elizabeth Clare, collected over 70 air samples from Hamerton Zoo Park in the UK. They used vacuum pumps with special filters to suck in the air — not just in the animal sleeping areas, but also in public outdoor parts of the zoo. After analyzing the samples, they found DNA from 25 different species, including tigers, lemurs, and dingoes. Seventeen of these were animals the zoo actually housed. Even more amazing, they picked up DNA from animals that were far away — sometimes hundreds of meters — and even from animals inside sealed buildings.
Somehow, the DNA still found its way into the air outside!
The second study took place at Copenhagen Zoo in Denmark. This team, led by Kristine Bohmann, used vacuum equipment and fans to gather samples in three places: an outdoor path between enclosures, inside the Rainforest House, and inside the okapi stable. In just 40 air samples, they found DNA from 49 different species — not just mammals, but also birds, reptiles, amphibians, and even fish! They even detected tiny guppies in a pond and a sloth hanging out in the rainforest exhibit.
Some of the DNA wasn’t from zoo animals at all. They picked up traces from local wildlife like squirrels, hedgehogs, mice, and even pets like cats and dogs. They also found DNA from animals that the zoo feeds to predators — like fish, cows, and chickens.
So, why does this matter?
Well, this method of collecting environmental DNA — or eDNA, as scientists call it — could be a game-changer. It means we could one day monitor wildlife without disturbing them. We might be able to track endangered species, catch early signs of invasive pests, or get a better picture of how healthy an ecosystem really is — just by sampling the air.
Both of these zoo studies were published in the journal Current Biology. They show that when it comes to animals, you don’t always have to see them to know they’re there. Sometimes, you just have to breathe in.
Sources:
https://www.cell.com/current-biology/fulltext/S0960-9822(21)01690-0,
https://healthsciences.ku.dk/newsfaculty-news/2022/01/which-animals-exi…
https://www.eurekalert.org/news-releases/938583
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