1) Earth Day. You can spend the day in nature – or savoring it on TV. There are cable marathons (see next two items) and the streamers are busy. Apple TV+ has the beautifully filmed “Big Beasts,” plus fiction ranging from kiddie idealism in “Jane” (shown here) to the sobering “Extrapolations.” Netflix has “Chimp Empire”; PBS Passport had a rich trove. Disney+ has its epic nature movies, plus “Secrets of the Whales” and the start of “Secrets of the Elephants.”
2) “Secrets of the Elephants” conclusion, 9 and 10 p.m., National Georaphic Channel, and more. Here are vivid portraits of opposites: At 9 p.m., rainforest elephants hide from (and sometimes attack) humans; at 10, the Asian ones co-exist easily. That’s followed at 10:50 p.m. by “Path of the Panther,” a movie-length portrait of efforts to film and preserve the Florida panther. Reruns (mainly “Animal Kingdom” and “Hostile Planet”) fill out the day.
3) “Chasing the Rains,” 8 p.m., BBC America, rerunning at 12:10 a.m., and more, The entire weekend (through noon Sunday) is filled with reruns of great BBC films – “Planet Earth,” “Frozen Earth,” etc. But there’s also this start of a new, three-Saturday series. We follow a cheetah mom mom and a wild dog, plus a matriarch elephant who must divert her herd when a river runs dry.
4) “The Wall” and “Weakest Link,” 8 and 9 p.m., NBC. Here are reruns of recent game-show epiusodes, the second one being a twins’ edition. That’s followed by “Saturday Night Live” reruns at 10 p.m. (with Issa Rae hosting and Justin Bieber as music guest) and 11:29.
5) ALSO: “NCIS: Los Angeles” (8 p.m., CBS) reruns an October episode that has the team link with the FBI, in search of a grisly group dubbed “the body stitchers.” That goes against hockey (8 p.m. ET on ABC, plus 4, 7 and 10 p.m., TBS); football (7 p.m., Fox, plus noon ESPN and 3 p.m. ABC); and basketball (1 and 3:30 p.m., TNT; 7 and 10 p.m., ESPN).