A male northern elephant seal surprised researchers at California’s Point Reyes National Seashore when he rushed into the ocean to save a drowning seal pup who was calling for their mother.

The pup’s mother called back in distress as her baby was suddenly pulled out to sea by the current. The baby seal was likely only two weeks old — not yet weaned and unable to swim — according to researchers. The waves appeared much stronger than the small pup.

That’s when the bull seal jumped in.

First, he approached the mother, then he rushed across the sand and into the water to reach the sinking pup, whose head was barely above the surface.

Next, the bull pushed the pup back to shore, using his larger body to keep the baby from being swept back out to sea – a process that took about 20 minutes from start to finish.

Once the baby was safely reunited with mom, the bull roared victoriously.

“We believe that our novel observation meets the definition of an altruistic act,” one of the researchers who witnessed the event wrote, according to IFL Science. “The pup benefited from the male retrieving it from being swept out to sea and drowning because it was too young to swim, and the male expended energy at a critical time that had the potential to impact his fitness.”

This elephant seal’s unexpected act of heroism shows how complex the social lives and feelings of other animals can be.

For another seal rescue story, learn how a seal pup tangled in a net was rescued and returned to the sea.