The Ballad of Big Al - page four

Living rough

	A swollen toe on Big Al's foot reveals healing following a bad injury.

At six years of age, Big Al had not quite reached adult size. His skeleton shows that life dealt him some heavy blows. This is not unusual for a predator like Allosaurus. Many skeletons show healed injuries but it was only the start for Big Al. Overall, he had 11 broken bones. The amount of healing around them tells us how long before his death each occurred.

The first to happen was a break to his tail, which seems to have been caused by a fall. The Ballad of Big Al shows him being being whipped by a Diplodocus tail and losing his balance. These tails were obviously formidable weapons. Another Allosaurus skeleton showed the clear mark of a tail across the ribcage, fracturing the ribs in a neat line.

His second wounds were a ripped arm and broken ribs. These would certainly have caused him considerable pain. He could have been injured trying to catch prey or fighting with another Allosaurus. The programme suggests he might have had a fight with a female. Female Allosaurus seem to have been larger and more heavily built than the males. This suggests that males didn't fight over the females. An inexperienced young male, though, could easily misjudge his first attempts at courtship. A large female Allosaurus was the most fearsome animal around at the time and could easily have caused these injuries to Big Al.

A deadly drought

Wounds which made Big Al an inefficient predator would have been very serious to him. His final injury - a broken toe - would have put an end to his hunting days. The break is similar to those seen in ostriches if they catch their feet whilst running. The bone around the break became seriously infected. The way that reptiles cope with infection is to try to kill the bacteria by raising their body temperature. This was most easily achieved by staying out in the sun. For the starving Big Al, however, at the time of a severe, ruthless drought, this behaviour proved fatal. His body was found in its final resting position - desiccated by the parching sun in a dried-out riverbed.