The Secret Lives of Wild Animals — Text-only | Flash Special Report
Seal


Movie
Join Weddell seals as they search for food and help researchers learn more about the marine life in the waters surrounding Antarctica.

VARIOUS SCENES—SEALS ON ANTARCTIC SHORE

NARRATOR:  Weddell seals—amazing animals…

SEAL LOOKING AT CAMERA 

incredibly well adapted to hunting in the

SEAL EMERGING FROM ICE

 ice covered waters of Antarctica.

SEAL UNDER WATER

The seals feed on fish; in particular,

ANTARCTIC SILVERFISH

Antarctic silverfish and

ANTARCTIC TOOTHFISH

 toothfish.

LEE FUIMAN

Professor Lee Fuiman.

SEAL WITH CAMERA MOUNTED ON HEAD
INSET:  SEAL RELEASED INTO OCEAN
FUIMAN:  We designed a study which used specially built equipment attached to the seals that enabled us to not only visualize

INSET:  UNDERWATER SCENES FROM SEAL’S POINT OF VIEW
the water in front of the seal with a video camera placed on the head of the seal, but also reconstruct the movements of the seal throughout its entire dive, because on the back of the seal, we had a computer
SENSORS ATTACHED TO SEAL’S BACK
with a lot of sensors attached to it that included the depth, the speed and the compass direction of the seal.
INSET:  ANIMATED SWIMMING PATH CHART
And from this information, we were able to reconstruct the three-dimensional swimming path of the seal from the start to the end of the dive and know exactly where the capture of the prey occurs.

SEAL EMERGES THROUGH HOLE WITH CATCH

Perhaps what was particularly unique about our work is the fact that we used a predator as a sampling device. 

SILVERFISH

And because of the new approach, we were able to learn new things about

TOOTHFISH

the species upon which the seals prey.

SILVERFISH
INSET:  FISH SWIMMING IN ANIMATED DEPTH CHART

NARRATOR:  They found that Antarctic silverfish swim deeper in the daytime than at night.

FUIMAN:  Now, that’s not particularly odd for open water fishes, to be deeper in the daytime than they are at night, but what’s really interesting is that these fishes are doing that

SUN SHINING ON ANTARCTIC  TERRAIN

in the Antarctic at a time of year when there is no sunset, that is, the sun is up 24 hours a day.

SILVERFISH NEAR SEA BOTTOM

And so, if these fish are responding to light intensity on the surface, by the time it gets down to the depth where they are,  it’s a very, very small amount of light and a very small difference in light between midday and midnight, so that’s very interesting.  They are shoaling fish—that is, they swim in groups. 

INSET:  SEALCAM RECORDS FISH CAPTURE

NARRATOR:  The researchers know this because the seals often caught at least five silverfish in a single dive. .. and sometimes, up to twenty.  And

VARIOUS SHOTS OF ANTARCTIC TOOTHFISH

what did the study show about Antarctic toothfish--another ecologically  important  fish species in McMurdo Sound, Antarctica?

FUIMAN:  Prior to this study, it was thought that Antarctic toothfish are bottom living fish. Well, it turns out that although we saw a relatively small number of toothfish,

INSET:  SEAL SWIMMING UNDER WATER

these occurrences all were in very shallow water.  Our seals never encountered toothfish at great depths. We can gain a lot of useful information about prey distributions and prey behavior from this approach of using predators as guided high-speed sampling devices,

SEAL UNDERWATER, APPROACHING HOLE IN ICE

and this approach could help us with other species of marine animals that are particularly difficult to study in the open ocean.

CLOSEUP OF TWO SEALS ON SHORELINE

Movie Credits

CONTENT
Lee Fuiman, University of Texas, Austin
Randall Davis, Texas A&M University
Paul A. Cziko, Laboratory of Arthur L. DeVries and C.H.C. Cheng, University of Illinois
Rob Robbins
Jesse E. Purdy, Southwestern University
Rear Admiral Harley D. Nygren, NOAA Corps (ret.)
Commander John Bortniak, NOAA Corps
Alexander Colhoun, National Science Foundation
Malcolm Ludgate ACS
T. M. Williams
Henry Kaiser, National Science Foundation
Mike Cameron, National Marine Mammal Laboratory

PRODUCTION
Cliff Braverman, National Science Foundation
Susan Bartlett, National Science Foundation
Nicolle Rager Fuller, National Science Foundation
Gwendolyn Morgan, National Science Foundation
S2N Media, Inc.