Pier 39 in San Francisco has hosted sea lions for decades. Tourists expect them. Locals love them. But nothing quite prepared the waterfront for Chonkers.

The massive Steller sea lion — estimated to weigh between 1,500 and 2,000 pounds — hauled himself onto the pier's floating docks and simply stayed, Fox News reports. Within days, he had a name, a fan base, and a viral video.

The pier's Instagram post of Chonkers spread fast. One visitor from Los Angeles, already running late, made a detour just to see him. "He's like a Volkswagen! He's so huge!" she told KQED.

Not Your Average Pier Animal

The sea lions that routinely lounge at Pier 39 are California sea lions — compact by comparison, weighing between 800 and 1,000 pounds. Chonkers belongs to a different species entirely. NBC Bay Area notes that Steller sea lions run about double the size of their California cousins.

The average male Steller tips the scales around 1,200 pounds and stretches close to ten feet. According to NOAA data, they can reach 11 feet and 2,500 pounds, Yahoo Life reports. Chonkers exceeds the average by a wide margin.

His species also carries a conservation weight. NOAA Fisheries lists the western population of Steller sea lions as endangered under the Endangered Species Act — making a healthy, thriving animal of Chonkers' size a genuinely significant sight.

Why San Francisco, Why Now

Experts point to food. The Farallon Islands — a protected marine sanctuary and known Steller sea lion breeding ground — sit roughly 30 miles west of the Golden Gate Bridge. Laura Gill, public programs manager at the Marine Mammal Center in Sausalito, told Smithsonian Magazine that Chonkers probably swam from there, passing under the Golden Gate and into the bay.

Pier 39 harbor officials confirmed the timing was no accident. "Right now, the fact that he's staying this long means that there's a lot of food source close by," harbor master Sheila Chandor told NBC Bay Area. It is anchovy season — a reliable, calorie-dense buffet for an animal of Chonkers' appetite.

Chandor, who has worked at the pier since 1985, confirmed Chonkers had dropped in for brief, one-to-two-day visits over many years. This time, he stayed for more than a month.

Chonkers likely traveled south from a breeding colony near the Farallon Islands, about 30 miles west of the Golden Gate Bridge.

A Dock Under Pressure

The extended visit has not been without complications. Chonkers' sheer mass presses the floating dock structure down to water level, and some harbormasters have flagged the structural strain as a genuine concern, Local News Matters reports.

Still, the pier's approach mirrors the one it adopted when California sea lions first arrived after the 1989 Loma Prieta earthquake. What began as an unexpected nuisance became one of the city's most beloved attractions after the Marine Mammal Center advised officials to let the animals stay, KQED notes. 

Fitting In by Sticking Out

Gill told Local News Matters that it was endearing to watch Chonkers try to snuggle with the California sea lions for warmth. "He's trying to fit in, but he sticks out like a sore thumb," she said.

He arrived alongside a juvenile Steller sea lion, though the younger animal departed after a few days, Smithsonian Magazine reports. Chonkers stayed put.

The Marine Mammal Center continued to monitor his movements and noted his appearances most often came in the early morning hours. By mid-day, he was usually back in the bay — hunting. A protected pier, calm waters, rich fish stocks, and a crowd of admirers: for one very large sea lion, San Francisco had everything.