Tom Siebel has been seriously injured after being trampled by an elephant.

Siebel was on a photo safari in Tanzania with a guide watching a group of elephants when one animal charged.

The guide fired at the elephant but missed. The animal attacked the guide before going for Siebel, breaking his ribs, trampling one leg and goring the other. Finally the elephant lost interest and the two men were able to radio for help, reports the San Jose Mercury News.

Siebel told the paper the two men were watching the animals from a distance of 200 yards: "There was no apparent reason, nothing that should have made it feel threatened," Siebel said. "It was quiet, and then the quiet stopped..."

Siebel was airlifted to Nairobi for treatment, eventually spending 18 days in four different hospitals. He is still recuperating at home from the attack which happened 1 August.

Siebel sold Siebel Systems to Oracle for $3.6bn in 2005. He now devotes much of his time to the Thomas and Stacey Siebel Foundation which funds university and drug education programmes. ®