A baby southern sea otter named Pup 681 is breaking hearts across YouTube with a video that has gone viral. The orphaned baby otter learns to float, play, and snack in the YouTube video filmed at Chicago's Shedd Aquarium. Watch it below!

The sea otter pup was rescued in California on September 30 and was placed in intensive care at Monterey Bay Aquarium for four weeks before moving to Shedd.

It takes a team of animal experts at the aquarium to teach the orphaned pup to learn essential otter behavior. Her species is rare - the southern sea otter has been decimated by the historical fur trade and modern threats such as oil spills and climate change.

Her species is listed as threatened by the U.S. Fish and Wildlife Service, and only about 3,000 animals remain in the wild.

National Geographic spoke to Karl Mayer, a sea otter conservationist and one of Pup 681's caretakers at the Monterey Bay Aquarium, to explain her behavior in the viral YouTube video, which has already received more than 3 million views.

Pup 681 become an orphan when she was found just north of Santa Cruz, an area where sharks often eat otters. It's possible something happened to her mother, or she was too weak to care for her.

Her squealing in the video communicates a range of otter emotions, such as discomfort when she's starting to get cold, contentment when she's happy, prior to defecating, or when she's being groomed. Mayer explains that she's probably vocalizing in the video to indicate she's a little cold in the water.

In the wild, Pup 681's mother would actively swim in the ocean, encouraging the baby sea otter to dive underwater and follow her. But in captivity her human caretakers don't swim with her, so they have to encourage the baby otter to develop the same behavior by prodding and motivating her.

Another thing Pup 681 needs help doing is staying dry. In the wild, mom would do most of the grooming. If a pup isn't dried properly the fur starts to clump, affecting the otter's development.

The purple stuff you see in the video are felt straps from a drive-through car wash, which act as fake kelp for the baby sea otter. The felt floats very much like kelp would and sea otters like to roll around and fall asleep in it. The purple felt mimics her natural environment.

Hopefully you understand a little more about otter behavior, but let's be honest - all you can really think about is how fluffy Pup 681 looks when she's dry and cozy in that towel!