About the Authors

Robert C. Lacy

rlacy@ix.netcom.com

Affiliation Chicago Zoological Society, Brookfield, Illinois, United States of America

Glen Alaks

Affiliation Chicago Zoological Society, Brookfield, Illinois, United States of America

Allison Walsh

† Deceased.

Affiliation Chicago Zoological Society, Brookfield, Illinois, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: RCL GA AW. Performed the experiments: GA AW. Analyzed the data: RCL AW. Wrote the manuscript: RCL. Designed the data collection software: RCL AW.