Gorilla Brothers Embrace in First Meeting After Years Apart brothers who were separated for years but never forgot each other. It is the story of a reunion. A rejoying and a reminder we're not the only creatures who know that family is forever. Here's dan harris. Reporter: Keysho and alf may be brothers but they were separated for three years at different zoos so whe it was time to be reunited, the fear was they wouldn't know each other and start fighting. But look at this, instant recognition. A bear hug and brotherly hoarse play. The posture, the universal symbol for hey man, I haven't seen you in years. Give me a hug. They really strengthen it. Reporter: Gorillas who share 99% of our dna are so similar to us. And it's apatient how much they care about family. The mom, the mom. Reporter: The moms as are tender with the babies and the dominate male protective. It shares our capacity for mischief. That's something I experienced first hand at our parent company's disney's animal kingdom theme park when i watched a vet give a gorilla ultrasound. Look at him try to grab me. Hey. Reporter: But fast assured me he was just messing around. If you put me on that right now, you would see my heart going very fast. Reporter: Messing around is something keysho and alf will have plenty of time to do. After the three-year absence, the plan now is for them to live out their days together. Dan harris, abc, new york. And we have word tonight from biologists, they're acting as if they have never been apart. Thank you for watching.