Mama bear carries 3 cubs on her back to swim across Wisconsin lake

Boaters in Wisconsin watched in awe as a mama bear swam across a lake -- carrying her three cubs on her back the entire way.

Nelda Powers was enjoying a sunset cruise on the Chippewa Flowage in June when she and her friends spotted movement in the lake.

The group watched as the bear patiently swam across the water just past the boat, all the while towing her three cubs on her back.

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"She's working so hard," one person could be heard in the video as another exclaimed, "Bless her heart!"

Once the bears made it across the lake, the mom and three cubs could be seen ambling up the embankment before running off into the woods.