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Natural History fISSN 0028-0712). incorporating 
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NATURAL 
HISTORY 
American Museum of Natural History 
Robert G. Goelet, President 
Thomas D. Nicholson, Director 
Vol. 90, No. 8, August 1981 
2 Authors 
6 The Importance of Mother’s Milk Graham Carpenter 
Cow's milk is ideal . . . for baby cows. 
16 This View of Life Stephen Jay Gou Id 
What Color Is a Zebra? 
24 A Naturalist at Large Niles Eldredge 
The Elusive Eureka 
28 Sky Reporter Stephen P. Maran 
Debut of an Interstellar Bubble 
32 Volcanoes and the Maya Payson D. Sheets 
Powerful eruptions have repeatedly devastated 
Central America and entombed a rare archeological record. 
42 Sleight of Wing Tex A. Sordahl 
Crafty avocets and stilts fool many predators and ornithologists. 
50 The Whale Behind the Tusk Randall R. Reeves and Edward Mitchell 
The narwhal's history and biology are isolated by Arctic ice 
and shrouded in myth. It’s future is cloudy, too. 
58 Weeds That Ride the Rails Robert M. Arnold 
Some plants thrive in the harsh railroad environment. 
66 I’d Rather Be a Messenger Jack M. Kugelmass 
When a winter storm paralyzes New York City, lowly bicycle 
messengers suddenly become heroes. 
76 Celestial Events Thomas D. Nicholson 
78 Books in Review Richard Edes Harrison 
Representing Earth 
82 Additional Reading 
84 At the American Museum 
The Nature Faker 
88 A Matter of Taste Raymond Sokolov 
Planter’s Lunch 
Cover: The fired-clay figurine was found at a Maya burial site of the Late Classic period 
(A.D. 600 to 900) on the island of Jaina. off the Yucatan Peninsula. Photograph by 
Lee Boltin. Story on page 32. 
1 
