A sea lion pup was kidnapped on a Los Angeles beach Sunday morning, and local police and the National Oceanic and Atmospheric Administration are investigating.

According to a witness, four people — two men and two women in their early 20s — were harassing a couple of pups on Dockweiler State Beach around 3 a.m. They were throwing items, including cinder blocks, at the young sea lions.

Then the four people wrapped one of the pups in a blanket and left in a dark-colored Honda Civic at 3:20 a.m.

When police arrived, they found the second sea lion pup, which is estimated to be about 10 months old, trying to make its way out of some brush. The animal was taken to Marine Animal Rescue (MAR).

As of Wed., April 22, the pup hasn't been located, and animal rights organization PETA offered up to a $5,000 reward for information to the arrest of the culprits.

Feeding or harassing sea lions is illegal under the Marine Mammal Protection Act, and keeping a sea lion is a federal crime — a dangerous one.

Sea lion pups are "really small, really cute, but they're dangerous. These are wild animals," MAR President Peter Wallerstein told The Associated Press.

The pups can bite harder than a pit bull, and they have "the dirtiest mouth of any mammal," according to Wallerstein.

In addition to potential injury, the kidnappers also face up to a year of jail time and fines up to $10,000.

Sea lion pups — especially one found on a beach that may be malnourished — require special care.

"The animal needs fluids, needs special treatments," Wallerstein said. "You can't just feed it dog food. It's not going to work."

Local rescue groups have been treating twice as many malnourished sea lions this as year as last year.

Scientists think warming waters are pushing away sea lions' typical foods, forcing mothers to leave their pups longer than normal as they search for food.

Typically, mothers leave their pups for only two to four days and return to nurse them, but this year researchers using satellite tagging have found that pups are being left for up to a week at time.

"As a result, young pups dependent on their mothers' milk to survive are not gaining weight and growing as they should at this time of year," according to NOAA's website. "Some pups may even be venturing off on their own in search of food. They end up stranding on beaches, weak and emaciated."

Related on MNN: