Why do elephants have hair? Research team searches for answer

In the study, Conor Myhrvold ’11, civil and environmental engineering professor Elie Bou-Zeid and mechanical and aerospace engineering professor Howard Stone analyzed photographs of elephant hair. They determined that the presence of hair helps elephants expel heat by conducting heat away from the body of the animal.

In most animals that maintain a stable internal body temperature, hair helps insulate the animal. This example is the first documented in which hair increases heat transfer and suggests a new possibility for why mammalian hair may have evolved in the first place.

Myhrvold, the lead researcher on the project, said he became interested in elephants while photographing wildlife in Africa before college. Myhrvold is a former photographer for The Daily Princetonian.

He said he was inspired to research the function of elephant hair during a class he took on environmental fluid mechanics, taught by Bou-Zeid. Myhrvold explained that he wondered whether the principles he learned in that class could explain why elephants had hair. He wrote his final term paper on the fluid mechanics of elephant hair and proposed to continue studying the topic with Bou-Zeid after the class ended.

“We knew there were one of three options. Either it wouldn’t have much of an effect, it’d help insulate or it’d help dump heat,” Myhrvold said. “We really weren’t sure until we did the study.”

After meeting with Stone, who had done research on heat regulation, the three decided to collaborate. The group developed modeling software to analyze photographs of elephant epidermal surfaces.

The results showed that the low density of hair over an elephant’s surface facilitated heat loss in a variety of conditions. Before these findings were released, many in the scientific community did not think elephants even had hair, while others who knew they did were unsure of its function.

The project began in January 2010 and spanned three years. Myhrvold continued researching for the project after he graduated.

“It’s something that if you care about it enough and you try to make a little bit of progress over a long time period and have short bursts of work, just being persistent and finding time, you can make a surprising amount of progress,” Myhrvold said.

Stone and Bou-Zeid also acknowledged the logistical difficulties resulting from the prolonged nature of the project. They said the project may not have come into fruition had it not been for Myhrvold’s perseverance and genuine passion for the subject.

“Conor is simply a walking encyclopedia of elephants,” Stone noted.

Myhrvold said he is interested in continuing his research by exploring differences in elephant hair density between species and age groups. He has already begun trying to obtain more photographs, which he said is the next step in his research.

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“I belong to the elephant listserv from the Cornell Lab of Ornithology,” Myhrvold said. “I convinced them to send out an email to over a thousand elephant researchers. It is a call for more elephant photographs.”

The findings from this study have been translated to 16 languages and featured in over 40 publications including CNN and MSNBC.

Due to an editing error, a previous version of this article misspelled several times the name of Conor Myhrvold ’11. The 'Prince' regrets the error.