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