Passage IV

NATURAL SCIENCE: This passage is adapted from the article "Shaggy, or Not So Shaggy: A New Look at Lions' Manes" by Anahad O'Connor (©2002 by The New York Times Company).

When people think of lions, many probably picture a regal creature with a luxuriant mane of blond hair covering its neck and shoulders. But a study suggests that the widespread image is misleading—that among male lions, a baldish head with sideburns may have been as prevalent in Africa as heavy manes, at least until recent years. The size of a lion's mane, the researchers concluded, appears to be a function of elevation and climate.

In 2001, Thomas Gnoske,a zoologist at Chicago's Field Museum of Natural History, spent his summer in the mountains along the equator in Tsavo, Kenya. Accompanied by Harald Schuetz, a photographer, Gnoske had set out to document the physical characteristics of lions living at different altitudes.

Gnoske and Julian C. Kerbis Peterhans, a professor of natural sciences at Roosevelt University in Chicago, had previously studied museum specimens, 19th-century accounts from hunters, historical photographs and scientific descriptions of lions. All of these things led them to suspect that manelessness was typical in some parts of Kenya and might have been widespread in Africa many decades ago. Gnoske and Dr. Kerbis Peterhans had learned of many accounts of elevation and latitude influencing mane development, so they set out to record the locations of more than 60 maneless lions.

In hot equatorial climates that are within 1,000 feet of sea level, they found, the lions often had hardly any mane at all. By contrast, lions at higher elevations and in colder climates had full, thick manes. At middle elevations, mane size tended to be intermediate, resembling a wreath extending from cheeks to shoulders. "Recently, lions that don't have manes have been described as freaks and isolated anomalies or were dismissed as young, juvenile lions," Dr. Kerbis Peterhans said. "But Tom was the first recent investigator to recognize that there is a complete range of variability in mane development and that a huge factor is climate."

Gnoske and Dr. Kerbis Peterhans believe that maneless lions have been depicted as anomalies because much of the earlier research was limited to a few habitats. Heavily maned lions usually live in well-protected tourist arcas or parks, while the habitats of maneless lions are generally unprotected. As a result. maneless lion numbers have steadily dropped over the years." The large-maned lions we think of as typical probably are mostly limited to the high-elevation plateau areas," Gnoske said. "Those are the places where most research has been done. So the public's idea of what socially and physically a lion is is not what the lion has been through history."

Scientists not connected with the study say they are not surprised by its findings. Dr. Graeme Patterson, assistant director of the Africa program at the Wildlife Conservation Society in the Bronx, points to cases where African lions that were taken to other continents adjusted to their new environments by changing physically. "Throughout history, lions that have been brought to Europe and North America adapted to the cold by growing thicker coats and additional hair," he said. "And in Africa, we've seen that lions in really high elevations have to adapt to that climate as well by growing more hair."

The study challenges several popular notions about mane development—for example, that the healthier a lion, the lusher its mane.

In addition to climate and elevation, hormones may also play a role in mane development. There are some cases of maneless nomadic lions living on high plateaus that do not defend territories, Gnoske said, and the reason seems to be low levels of male hormones.

But not having a mane may actually be a benefit. Recent studies show that in some primate species, like orangutans and mandrills, adult males may actually inhibit development of their masculine physical characteristics—through suppression of testosterone—to be less conspicuous and escape conflict with rival males. Dr. Kerbis Peterhans speculates that this also applies to some lions. One with a reduced mane, he said, can sneak around another's territory virtually undetected and decide if it wants to challenge the pride male or remain on the periphery. "When a lion sees another with a mane he sees it as a threat," he said. "But if it is maneless he'll think it is immature and will ignore it. So the strategy is to look like a juvenile to avoid potentially deadly confrontation."