A 5-week-old orphaned southern sea otter pup arrived at Chicago's Shedd Aquarium last week and is receiving round-the-clock care from staff.

Weighing in at just under 6 pounds, the female pup, who’s currently referred to as "Pup 681," is the second pup from the threatened southern sea otter population to arrive at Shedd.

The pup was discovered on a California beach on Sept. 30 when a local resident heard the newborn's cry.

The tiny, newborn otter couldn't be retrieved that evening due to the remote location and setting sun, but on Oct. 1 scientists from the California Department of Fish and Wildlife and the Monterrey Bay Aquarium's Sea Otter Program determined the pup was orphaned, so they rescued her.

The pup was taken to the aquarium where she was estimated to be only about a week old and weighed in at just 2 pounds.

This "is tiny for a newborn sea otter, and she had been separated from mom for at least 16 hours," Karl Mayer, animal care coordinator for the Sea Otter Program, said in a news release. "This meant it was critical that we begin to get calories into her as quickly as possible."

The Sea Otter Program works with other aquariums and wildlife rescue facilities to respond to every sea otter that comes ashore in distress along the California coast. Over the past 25 years, nearly 700 sea otters have come through the program.

Sea otter pups stay with their mothers until they're 8 months old, during which time they require constant care. The Shedd Aquarium is one of the few U.S. facilities with the available space, staff and experience to provide appropriate care for them.

Shedd staff agreed to provide Pup 681 with a permanent home, and once she was stable, the tiny otter made the trip to Chicago.

Currently, the pup is behind the scenes at the aquarium where a rotating schedule of six to eight animal care experts provide her with care and attention 24 hours a day. In addition to caring for the pup, staff are also helping her learn important behaviors like foraging, feeding and grooming.

Staff say the pup is reaching new milestones every day, including taking formula from a bottle, eating solid foods like shrimp and clams and climbing over to towels when she gets wet to help her groom and regulate her body temperature.

Instead of blubber to keep them warm, otters have thick hair that consists of two layers. They spend up to four hours a day grooming the fur because if it's not immaculate, they risk dying of hypothermia.

"It truly takes a village to rehabilitate a young sea otter," said Tim Binder, Shedd’s vice president of animal collections. "Our animal care team is teaching the pup how to be an otter."

Below, check out some photos of little Pup 681, and don't miss the adorable video of her arrival at the aquarium.

Otter Pup 681 with bottle

Otter Pup 681 eats snack

Otter Pup 681 drinking from bottle

Otter Pup 681 in towel

Otter Pup 681 playing with toys

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Laura Moss writes about a variety of topics with a focus on animals, science, language and culture. But she mostly writes about cats.

Otter 101: Orphaned pup learns the ropes from humans
Shedd Aquarium staffers providing the 5-week-old otter with constant care and learning opportunities