All by myself

Wolfgang Dittus has spent over half a century studying the toque macaques of Sri Lanka. His life’s work — and what he’s discovered — is revealed in “A Life Among Monkeys,” a documentary told from the perspective of the animal whisperer himself.

8 p.m. Smithsonian Channel

Sea worthy

“Saving the Dead Sea” looks at the modern-day crisis facing the body of water name-dropped by Cleopatra, Aristotle and Moses. Because this is an episode of “Nova,” the one-hour documentary is jam-packed with science, but don’t worry; there won’t be a test.

8 p.m. TPT, Ch. 2

Wax on, wax off

“Cobra Kai,” a continuation of the “Karate Kid” saga and one of the more delightful surprises of 2018, returns for a second season. William Zabka, who reprised his role as the bully Johnny Lawrence, was a revelation the first time around. Expect the actor to dig even deeper in these new episodes, especially with his abusive coach John Kreese (Martin Kove) re-entering the picture.

Now streaming on YouTube Red

Neal Justin