An African elephant was born over the weekend at the San Diego Wild Animal Park, it was announced Monday.The calf, born Sunday around 2 a.m., is the 13th African elephant in the herd.Campers who spent the night at the park said they were awakened by elephant trumpeting."The herd was celebrating," said Brittany Trawick, the park's elephant keeper. "Elephants are social animals. When a calf is born, they let everyone know."The unnamed calf is the second offspring at the park of Ndlulamitsi, whose name in the SiSwati language means "taller than trees."Ndlula, for short, was brought to the Wild Animal Park in 2003 from Swaziland shortly before elephants there were to be culled because of overpopulation.The gestation period of an African elephant is 22 months, and the average calf weighs between 250 and 300 pounds. Vital statistics of the new calf were not provided.