A screenshot of a map showing case counts of COVID-19 reported in different animal species, part of an interactive COVID data tracking dashboard rendered by Complexity Science Hub Vienna. The drawings represent the type of animal, including both domestic and wild; the size of the bubbles reflects the number of cases in each locale. Complexity Science Hub Vienna/Screenshot by NPR hide caption
Two white-tailed deer forage in Pennsylvania's Wyomissing Parklands. At the end of 2021, researchers swabbed the noses of 93 dead deer from across the state. Nearly 20% tested positive for the coronavirus. Ben Hasty/MediaNews Group/Reading Eagle via Getty Images hide caption
A hamster named Marshmallow was dropped off at the New Territories South Animal Management Centre in Hong Kong on Jan. 19 over concerns that pets were spreading the coronavirus to humans. Thousands of small animals were culled after hamsters tested positive in a pet store. Bertha Wang/AFP via Getty Images hide caption
A hamster sits in a cage after being adopted by volunteers who stopped an owner from surrendering it to the government outside the New Territories South Animal Management Centre on January 20, 2022 in Hong Kong, China. Louise Delmotte/Getty Images hide caption
A Hong Kong hamster that evaded the cull. Bertha Wang/AFP via Getty Images hide caption
Spinning on the hamster wheel allows Mr. Goxx to select a cryptocurrency to trade. Choosing one of two tunnels to run through allows him to buy or sell. YouTube/Screenshot by NPR hide caption
A hamster perks up at a cemetery in Vienna in May 2017. The common hamster is at risk in parts of Europe, but conservation efforts have improved its chances of survival. Courtesy of Michaela Vondruska hide caption