The newborn twin panda cubs at Zoo Atlanta are getting stronger every day and are preparing to make their debut.

In a new video taken of the cubs at 70 days old, the zoo's veterinarian staff gives them a check-up on the exam table in the nursery, where they are regularly weighed and measured. "Cub A" and "Cub B," as they are affectionately known for now, are seen in the video nuzzling up to one another - a sign they are starting to recognize their twin.

"Their eyes and ears have recently begun to open, so they are gradually responding more and more to the sights and sounds of their environment," according to the zoo. "They're not old enough to walk, wrestle, or play, but each is becoming more aware of the other."

While they may look identical to an untrained eye, keepers can tell the twins apart by marking and coloration around their mouths.

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The cubs, born July 15 to 15-year-old mom Lun Lun, are the first giant pandas to be born in the United States in 2013 and the only giant panda twins ever to survive in the U.S.

In keeping with Chinese tradition, the pandas will be named when they turn 100 days old. Until then, they are known "Cub A" and "Cub B," but that will soon change and " Good Morning America" viewers will have a chance to weigh in on the twins' names.

Stay tuned to "GMA" to find out how you can vote on which name the panda cubs will get.

One lucky fan will win a trip to Atlanta to be part of the cubs' 100 Day Naming Celebration at Zoo Atlanta and have an exclusive behind-the-scenes encounter for two in the giant panda nursery. Click here to find out how to enter the Panda Extravaganza Sweepstakes!

Click HERE to watch Zoo Atlanta's around-the-clock "Panda Cam."