Baby sloths are completely irresistible. Perhaps it's because their faces are shaped in a permanent smile. Or maybe it's because they love to hug -- stuffed animals, trees, other sloths, people. It could simply be their signature comical slowness. And orphan baby sloths? Well, If you think you can resist them, try watching this video only once. The trailer is just a taste of the new documentary, "Too Cute! Baby Sloths," airing Saturday Dec. 17 at 8 p.m. ET on Animal Planet. The show is filmmaker Lucy Cooke's follow-up to her wildly popular internet video "Meet the Sloths." Both were shot at the Aviarios Sloth Sanctuary in Costa Rica. The sanctuary takes in any sloth in need, but is mostly populated by orphaned baby sloths who lost their mothers to power lines or road traffic or other accidents. There are currently around 160 sloths there. I can attest that it's an amazing place, and well worth a visit (or a donation). Cooke spent a year filming the lives of the sloths there, from potty-training to pole-climbing class. The new documentary follows five main stars, and according to Cooke, uncovers a surprisingly active (though slow) lifestyle filled with love, loss, lust and humor. (There is even footage of some super slow sloth sex.) Cooke shared with Wired some exclusive images of the sloths that star in the documentary and some of the other sanctuary residents, such as the photo below of an orphaned two-fingered sloth named Toby.

This tiny three-fingered sloth is named Mira. She is especially small, and her caretakers suspect she may be a dwarf sloth, as she doesn't seem to grow.

"This is baby Sebastian getting rather curious during the filming of my sloth sanctuary documentary," Cooke writes on her Slothville website. "Sebastian loved the camera and the camera loved him! You will notice he is rather snazzily dressed for a baby sloth. Sebastian had been a bit poorly and so he was wearing specialised sloth pyjamas made out of sports socks to keep him super snuggly."

"Violet is a patient at the ‘slothpital’ -- the sanctuary’s dedicated hospital for sick sloths," Cooke writes on her Slothville website. "Here you can see her hugging her twin brother Sebastian and feeling rather pleased with her jazzy bandages. Sloths are Jedi masters of the hug and these two are inseparable."

Mira visits the "slothpital" for a check-up.

"The sloth sanctuary is happy to care for any sloth in need but they have to adhere to the one house rule. No sex between inmates," Cooke writes on her Slothville website. "This has been particularly tough for Randy (above). Randy was the local wild Lothario sloth who’d rock up looking for some action any time one of the sanctuary’s female sloths went into heat. The fact that he could never reach the sexy sirens didn’t stop him patrolling the grounds in the hope of getting close." "One day another male turned up and a fight broke out. A very slow fight which saw Randy fall to the ground and break his arm. This of course may well have been a clever ploy by sneaky Randy to bust into the sanctuary and get closer to the girls. He was rescued and had to have a titanium plate fitted. Now he’s the bionic sloth but sadly still no closer to getting any action with the sanctuary’s lady sloths."

A two-fingered baby sloth gets a meal.

The sloths were more than passive participants in the film-making. This baby sloth's orange hue is the result of being bathed in a concoction made from achiote, a shrub whose seeds are used for food coloring and flavoring, that rids the animals of mange. The orange dye-job sticks around for a few weeks.

Buttercup was the first sloth at the sanctuary. She is treated like a daughter by sanctuary founder Judy Avey-Arroyo, who has spent 20 years rescuing and caring for orphaned and injured sloths.

A baby sloth checks out the camera.

A three-fingered sloth poses for the film title sequence of "Too Cute! Baby Sloths," which airs on Animal Planet, Saturday, Dec. 17 at 8 p.m. ET. You can see more clips of the sloths on the Animal Planet website .