James Gunn Explains Groot's Age Gap In Avengers: Infinity War

When Groot returned alongside the Guardians of the Galaxy in Marvel Studios' hit sequel, the single-minded space tree was now a new entity known as Baby Groot: a toddler version of the breakout character but without the memories and experiences of adult Groot.

"Baby Groot is not Groot," director and writer James Gunn explained in March. "He's a different character and he does not have that character's memories," Gunn said, adding that resurrecting Groot as-is would have rendered Groot's heroic move a "meaningless sacrifice."

Audiences may have seen the last of Baby Groot in Guardians of the Galaxy Vol. 2 — one of Vol. 2's post credits scenes catches up with the Guardians an undetermined amount of time later, revealing Groot as a stubborn, phone-obsessed "kid" — but there's a new iteration of Groot to look forward to: Adolescent Groot.

It's Adolescent Groot who takes part in Avengers: Infinity War, which will reportedly catch up with the Guardians four years after Guardians of the Galaxy Vol. 2., and it's Adolescent Groot who audiences saw in Infinity War footage revealed exclusively at D23 Expo and San Diego Comic Con.

"People are asking about how fast Groot grows, because in his appearance in the Infinity War trailer he was an ADOLESCENT (not a "teen" as has been reported in many places). This is exactly the same state of growth you see in the post credits scene of Vol. 2: Adolescent Groot," Gunn wrote in a Facebook post.

"In terms of how fast Groot grows overall, I can tell you this: Baby Groot appears two months after the Infant Groot we see at the end of Vol. 1," Gunn explains, revealing Adolescent Groot's first appearance is "years after the ending of Vol. 2."

"Groot and humans do not grow at some exact exchange rate," Gunn said of Groot's alien biology. "So, although two months seems to be about two years (as Baby Groot seems to behave roughly like a two year old), it is not fair to assume that every month is a year to Groot."

Gunn concludes with the nugget that fans will be in suspense for quite a while, as "it will take years to show you how Groot goes from infancy to adulthood." Adult Groot could return in Guardians of the Galaxy Vol. 3, which will once again be scripted and directed by James Gunn.

Avengers: Infinity War is described by Marvel Studios as the culmination of everything in the Marvel Cinematic Universe since Iron Man in 2008. The movie is filming now under directors Anthony and Joe Russo, from a screenplay by Christopher Markus and Stephen McFeely.

The expansive confirmed cast includes Robert Downey, Jr., Chris Evans, Chris Hemsworth, Mark Ruffalo, Jeremy Renner, Scarlett Johansson, Tom Holland, Elizabeth Olsen, Paul Bethany, Sebastian Stan, Benedict Cumberbatch, Benedict Wong, Chris Pratt, Zoe Saldana, Karen Gillan, Vin Diesel, Dave Bautista, Bradley Cooper, Pom Klementieff, and Josh Brolin as the villain Thanos.