When you go to the zoo, you are breathing the DNA of the animals inside it

Researchers went to a zoo and used a small fan to blow air into a filter. They analyzed what the filter caught and found DNA from the critters' "breath, saliva, fur, or feces."

No wonder the zoo smells so funky!

From Science Daily:

In each study, the researchers detected animals inside the zoo and wildlife from the nearby. Clare's team from Queen Mary University of London detected DNA from 25 species of mammals and birds, and even DNA belonging to the Eurasian hedgehog, which is endangered in the UK. Bohmann's team at the University of Copenhagen team detected 49 non-human vertebrate species, including mammal, bird, reptile, amphibian, and fish species. These included zoo animals like the okapi and armadillo and even the guppy in a pond in the tropical house, locally occurring animals like squirrels, and pest animals like the brown rat and house mouse. Further, they detected fish species used for feed for other animals in the zoo. Both teams took extensive measures to check that their samples were not contaminated, including by DNA already in their labs.