Wild Things:
Life as We Know It
Butterflies, clicking antelopes, creatures of the deep and more
- By Amanda Bensen, T.A. Frail, Megan Gambino, Anika Gupta and Abigail Tucker
- Smithsonian magazine, January 2009

A study suggests that Swainson's thrushes drowse with their eyes open. (Birdfreak.com / Flickr)
Name: Catharus ustulatus, or Swainson's thrush.
Summers: In Canada and the northern United States.
Winters: In Mexico and South America.
Flies: By night, at least when migrating.
Sleeps: Surreptitiously. Scientists have long wondered how migrating birds, after flying all night, apparently make it through the day without sleeping. A new study of brain waves among captive Swainson's thrushes suggests they drowse with their eyes open; nap for mere seconds; and doze with one eye open, resting one side of their brain at a time. They could be catnapping while watching out for the cat.
Additional Sources
"The thermohaline expressway: the Southern Ocean as a centre of origin for deep-sea octopuses," Jan M. Strugnell et al., Cladistics, November 11, 2008
"Knee-clicks and visual traits indicate fighting ability in eland antelopes: multiple messages and back-up signals," Jakob Bro-Jørgensen and Torben Dabelsteen, BMC Biology, November 5, 2008
"Sea Snakes (Laticauda spp.) Require Fresh Drinking Water: Implication for the Distribution and Persistence of Populations," Harvey B. Lillywhite et al., Physiological and Biochemical Zoology, November/December 2008
"Hindwings are unnecessary for flight but essential for execution of normal evasive flight in Lepidoptera," Benjamin Jantzen and Thomas Eisner, PNAS, October 28, 2008
"Daytime micro-naps in a nocturnal migrants: an EEG analysis," T. Fuchs et al., Biology Letters, November 5, 2008










Comments (2)
This is great information for my project thnx <3
Posted by Jacqueline Molina on March 30,2011 | 06:15 PM
Although I had lived in Kenya for 30 years, I had never heard eland knees click. Thanks for recording this extraordinary bit of natural information. I wonder if my son who works near Masai Mara has ever heard this??!!
Posted by Ann Goss on April 19,2010 | 07:48 PM