The secretive indri (Indri indri) of Madagascar, the largest living lemur. It is also critically endangered and highly evolutionarily distinct with no close relatives, which makes its branch one of most precarious on the mammal evolutionary tree. In the likely event that the indri goes extinct, we will lose 19m years of unique evolutionary history from the mammal tree of life. (Photo by Pierre-Yves Babelon/Aarhus University)

Revelers dance at the Old Settler's Music Festival in Driftwood, Texas, U.S. on April 22, 2017. (Photo by Mohammad Khursheed/Reuters)

Students from Cambridge University make their way home after celebrating the end of the academic year at a May Ball in Trinity College on Tuesday, June 21, 2022. The first official May Ball in Trinity College's grounds was held in 1866 with the tradition quickly spreading to the other colleges. (Photo by Joe Giddens/PA Images via Getty Images)

A Grevy’s zebra gets itself noticed at ZSL Whipsnade Zoo in Whipsnade, England on April 20, 2018. (Photo by Tony Margiocchi/Barcroft Media)

A fox pounces on a mouse in the snowy hills on the border of the Czech Republic and Slovakia. (Photo by Johnny Krüger/Mediadrumimages)

African ostrichs are seen during sunny autumn day in the largest ostrich farm “Nornieki” in Snepele, Latvia, 18 October 2021. (Photo by Toms Kalnins/EPA/EFE)

A frog sits on a leaf and instead of seeing a reflection of itself in the water below, it sees a snail, attached to the bottom of the leaf, in a fish tank in Vietnam. (Photo by Duong Quoc Dinh/Solent Ne/SIPA Press)

In this undated photo made available by journal Nature on January 15, 2014, a northern bald ibis (Geronticus eremita) flies in Tuscany, Italy. A new study released Wednesday, January 15, 2014 says the birds choreograph the flapping of their wings, getting a boost from an updraft of air in the wake of the flapping wings by flying behind the first bird and off to the side. When a flock of birds take advantage of these aerodynamics, they form a V. (Photo by Markus Unsöld/AP Photo)