If the CGI apes stole the show from their less lifelike human counterparts in “Rise of the Planet of the Apes,” the two groups are more evenly matched in “Dawn of the Planet of the Apes.” The latest chapter in the rebooted sci-fi franchise charts the emergence of a culture of super-intelligent chimpanzees, gorillas and orangutans and the simultaneous decline of the human race, after it is nearly destroyed by a laboratory virus. In the process, the movie presents us with two equally engaging and frustrating families: one human, and one ape.

“Family,” of course, can refer to more than the nuclear unit of parents and children. Although there are two families at the center of this highly watchable, post-apocalyptic popcorn flick — the chimp leader, Caesar, with his “wife” and two sons on one side, and a trio of human survivors on the other — “Dawn” is also about the broader use of that term. It’s the story of the struggle between the family of Man and the family of Ape.

It’s also the story of struggles within those two groups.

As the film opens, Caesar — movingly played by Andy Serkis with a mix of motion-capture technology and digital animation — is living peacefully in the woods outside San Francisco with his pregnant partner, Cornelia (Judy Greer), and their adolescent son, known as Blue Eyes (Nick Thurston). But an incursion by members of a colony of virus-resistant humans from the other side of the Golden Gate Bridge leads to tension, not just between Man and his closest nonhuman cousin, but between factions from each group that can’t agree whether to trust or to attack their neighbors. It is no accident that the source of conflict here is energy, in the form of an inactive hydroelectric plant just next door to the ape encampment. The humans claim a right to it, in order to satisfy their addiction to power.

Leading the human negotiating team is the pacifist Malcolm (Jason Clarke) and his son (Kodi Smit-McPhee) and partner (Keri Russell). Their job is made harder by the presence in their party of an anti-ape hothead (Kirk Acevedo), and by their colony leader (Gary Oldman), who would just as soon shoot first and ask permission to use the power plant later.

Similarly, Caesar’s decision to compromise with the humans — a trait picked up from his human “father” in the last film (James Franco, seen in a brief video clip) — clashes with the ape Koba (Toby Kebbell). An embittered chimpanzee who still bears the scars from his years in a research laboratory, Koba hates and mistrusts all humans, as well as some more highly evolved members of his own kind.

This sets up parallel struggles, not just between species, but within them. The film’s plentiful action is thrilling at times — even if some of the ape-on-ape fight sequences don’t fully register as real — and the cinematography has a dark and dramatic intensity.

More important, the apes’ feelings are conveyed beautifully, mainly through facial animation and sign language. Though only one or two of them actually speak, they are remarkably expressive characters. Introduced in the last film, Maurice the orangutan (Karin Konoval) is an audience favorite. Imprisoned at one point by Koba, Maurice, with his soulful eyes, is especially good at eliciting our sympathy.

Director Matt Reeves (“Cloverfield”) has clearly marshaled a lot of expertise from the field of primate behavior here, not just in terms of the apes’ physical gestures and movement, but in their emotions as well. “Dawn” may be a silly summer move, but the apes in it are almost as believable as anything in a documentary about the work of primatologists Jane Goodall or Dian Fossey. Caesar, particularly, is as poignant as the protagonist of “Project Nim,” the 2012 documentary about the sad life of a chimp who was taught sign language.

“Dawn of the Planet of the Apes” works both as allegory and action-adventure film. The internecine conflict between apes mirrors the troubled history of our own race. It isn’t just that Caesar is a better ape than Koba, but that both of them, tragically, embody a dual nature that is all too recognizably human.

★ ★ ★

PG-13. At area theaters. Contains violence and brief crude language. 122 minutes.