Board Thread:Boruto Discussions/@comment-30881771-20180425153347/@comment-734582-20180425184420

Elveonora wrote: I agree that there is like an imprint of Shukaku's chakra inside of Gaara. It's very little, but it's there. Either that or Shukaku gave him a tiny bit of chakra to keep in touch, similar to how was done with Naruto. Gaara seemed to be on much better terms with Shukaku in the 4th war climax, so it's probable that he gave him a bit of chakra afterwards.