Unlike their more notorious kin, horn sharks (Heterodontus francisci) aren't exceptional swimmers. They spend their days hiding out amongst the kelp fronds or on the seafloor, and hunt only small, slow-going prey like urchins and crabs. In fact, they sometimes hobble along atop their pectoral fins to get the job done.
In theory, that leisurely lifestyle should make these small sharks particularly vulnerable to predation from the state's 350-kilogram (770 lb) marine mammals. But for the team at Newport Coastal Adventure, who caught the clash on camera, it was rather surprising. "This is the first time I have ever witnessed one eating a horn shark," skipper Ryan Lawler told us.
Sea lions in the area have been chowing down on sharks for as long as we've been observing them – they've even been known to take out entire aggregations in the area. But horn sharks' shape makes them a tough swallow. "Horn sharks have prominent 'horns' or spikes on their dorsal fins as a defense against predators," he says.
The thrashing scene occurred in some 180 feet (54m) of water, and that has led some to suspect this shark may have been dead before the sea lion found it. But while horn sharks do tend to stick to shallow water, they've also been spotted as deep as 152 metres, and they regularly move into deeper water during winter.
Whether or not this was a one-off meal is hard to say with certainty, and we don't know that this sea lion actually swallowed the entire shark – but it sure didn't appear to struggle much with the takedown!
Top header image: simpliciter/Flickr