In late 2021，a scientist named Bohmann from the University of Copenhagen in Denmark and her team found a new way to study animals.They discovered many types of animals in the Copenhagen Zoo and around it，even when the animals were not inside the zoo.They used a special method to find the animals：they absorbed air through a filter （过滤器） to get DNA from it.
The air we breathe is mostly made up of nitrogen （氮气） and oxygen，but it also has a tiny bit of DNA.Animals drop bits of their DNA into the environment all the time，from their skin，waste，fur，feathers and more.This DNA can help us understand what animals live in a certain area.Scientists have found DNA in rain，soil，and honey，and even in water.Air is everywhere，so it's easy to take samples from it.It's easier to collect DNA from the air than people thought.
At a zoo in Cambridgeshire，a biologist named Elizabeth Clare from York University in Toronto did some tests.She used a special vacuum （真空吸尘器） to get DNA from the air near the zoo's fences.She found DNA from many different animals，even from far away.One type of lemur （狐猴） was found everywhere，but another type was never found，even when she tried right next to it.Clare thought the tests were very successful.
At first，Clare and Bohmann thought their experiments might not work at all.But they were surprised to find lots of different animals，49 in Denmark and 25 in England，both inside and outside the zoo.They even found DNA from fish that were used as food for other animals.Bohmann said it was amazing.
This new way of using a DNA vacuum could help us find out where endangered animals live and protect them better.It could change how we watch over different types of animals and help us make better decisions about the environment.
