April 2020, ScientificAmerican.com 1April 2020VOLUME 322, NUMBER 400
Photograph by Igor Siwanowicz
50
A S T R O N O M Y
28 New View of the Milky Way
A recent effort to map the spiral structure of our galaxy has produced an
unprecedented view of our cosmic home. By Mark J. Reid and Xing-Wu Zheng
CONSERVATION
36 Cat vs. Woodrat
Feral cats kill a lot of wildlife, but methods to solve the problem are controver-
sial and under studied. In Key Largo, Fla., conservationists are trying new ways
to save the endangered woodrat without having to exterminate felines.
By Carrie Arnold
EVOLUTION
44 The Trouble with Teeth
Our teeth are crowded, crooked and riddled with cavities. It hasn’t always
been this way. By Peter S. Ungar
B I O L O G Y
50 Extreme Survivor
A tiny, six-legged creature called Tullbergia has persevered through more
than 30 ice ages in the harshest badlands of the Trans antarctic Mountains.
Scientists are just starting to figure out how. By Douglas Fox
ANTHROPOLOGY
58 The Aid Tsunami
The ocean took their loved ones and destroyed their villages. But it was
misguided disaster relief that destroyed their way of life.
By Ajay Saini and Simron J. Singh
ON THE COVEr
Despite centuries of study, astronomers are only
now learning how our home galaxy, a spiral
of at least 100 billion stars spanning more than
100,000 light-years, really appears from outside.
New surveys are revealing the Milky Way’s
structure in more detail than ever before.
Illustration by Ron Miller.© 2020 Scientific American