reports. reporter: keisho and alf may be brothers but they had been separated for three years at different zoos. when it was time to be reunited the fear was they wouldn t know one another and start fighting. but look at this, instant recognition. a bear hug and then a little brotherly horseplay. their posture, universal signal for, hey, man, i haven t seen you in years. give mef a h . give me a hug. the way they recognize is two family members, strange and wonderful to see. reporter: gorillas who share 97% of our dna are so similar to us. i spent time with a group of gorillas in africa and it oh, yeah. go back to his mom. reporter: gorillas share our capacity to form deep attachments and our capacity for mischief. something i experienced firsthand at our parent company
reporter: they may be brothers, but they had been separated for nearly three years at different zoos. when it was time for them to be reunited, the fear was they wouldn t know one another and start fighting. but look at this instant recognition. a bear hug and then a little brotherly horseplay. their posture, the universal signal for hey, man, i haven t seen you in years. give me a hug. when they recognized each other, it s just like two family members joining together again. it s really strange and wonderful to see. reporter: gorillas who share 97% of our dna are so similar to us. i recently spent time with a group of gorillas in africa, and it was immediately clear how much they, like us, care about family. little one, little one. oh, yeah. go back to his mom. reporter: gorillas share our capacity to form deep attachments and our capacity for mischief. something i experienced firsthand at our parent company disney s animal kingdom theme park when i watched the vets gi