India, April 16 -- In a remarkable display of instinct, a herd of elephants at the San Diego Zoo formed a protective "alert circle" around their young during the 5.2 magnitude earthquake that struck Southern California on Monday morning.

The quake, which occurred around 10:08 a.m. near San Diego, was strong enough to be felt in Los Angeles, according to the US Geological Survey. While the tremors caused furniture to shake and glass items to shatter across homes in the region, the elephants at the zoo responded with calm coordination.

As soon as the ground began to tremble, the group of five adult elephants moved quickly to the centre of their enclosure and surrounded the youngest members of the herd. The San Diego Zoo shared video foota...