Whether you like your critters ultra-cute or totally scary, PBS has you covered Wednesday night.

The Nature series, at 9 p.m. ET (check local listings), finishes up its new fall offerings with the first of a two-part feature called The Story of Cats.

That would be the four-legged felines, not the Broadway show, and while the focus here is more on large wild species like tigers, not your adorable Fluffy, the truth is that all cats have an endearing demeanor.

Lest anyone start feeling too bonded to the animal kingdom, however, The Story of Cats is followed at 10 p.m. ET (check local listings) by a Secrets of the Dead episode enticingly titled Graveyard of the Giant Beasts.

It seems that after the dinosaurs had become extinct, some 65 million years ago, the handful of animal survivors on Earth included giant snakes and crocodiles.

We do mean giant. Fossilized bones found in Colombia indicate one snake, which was given the name Titanoboa (right), reached 43 feet in length and weighed around a ton.

Scientists speculate it spent most of its time lounging on the bottom of tropical lakes and lagoons, waiting for food to swim by. Food being pretty much everything else – except the giant croc.

That supersized fellow was maybe three times bigger than today’s crocodiles, which are already large enough that few of us want to interact with them.

Scientists found the snake first and in 2009 they announced its apparent former existence. They also declared that once the dinos were gone and the planet finally warmed up again, this snake became the Earth’s apex predator, at least in tropical swamps.

Alas, fans of giant snakes got to enjoy that designation for only five or six years. Once the croc’s bones were located, it was clear that the snake had better have slept with one eye open.

Nature shows love to show critters making dinner out of each other, we all know that. So you can imagine how much fun Secrets of the Dead has with two monstrous predators swimming around in the tropical ooze.

Now snakes can eat crocodiles. They do it regularly these days in the Everglades. But size matters, because snakes swallow their prey whole and if Titanoboa swallowed something large and scaly enough, its stomach could rupture.

Crocs, on the other hand, followed mother’s advice. They cut their food up – well, actually they rip it apart with their teeth – and take small bites.

So a giant croc could whack a giant snake, stash the carcass under water and nosh for days.

Ah, nature.

The Story of Cats doesn’t skimp on hunting and eating, either, since that’s a full-time job for big cats in the wild.

This special notes that it’s a hard job, but also one for which cats are clearly equipped. Some member of the species exists pretty much everywhere in the world, from the snow leopards and fisher cats of the Arctic to mountain lions that have set up dens within the city limits of Los Angeles.

Stealth and speed are common denominators among the species. So is patience. So is an astonishing ability to jump, which may only get your calico cat a spot in the afternoon sun on the window bench, but in the wild can mean batting a bird off a low tree branch for dinner.

The Story of Cats can’t answer the disturbing question of what your pet cat is really thinking. It does provide more clues to why he’s behaving like that.

It also confirms that cats make way better pets than 43-foot snakes.