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upper horn from the older male punched through the right side of the younger one's
skull, leaving a round wound about the width of the older male's horn.
Injuredbadly,althoughnotfatally,theyoungermaleturnedandbeganlimping
away. His right humerus also had been fractured by the impact and started to
ache.Accordingly,histrackwayacquiredanewasymmetry,withbothlegsstepping
shorterontherightsideandashallowerimpressionintheright-frontfootprintashe
put less weight on it. The larger male
Triceratops
, satisfied for now, walked away
but stopped periodically to turn and look, making sure that no further bad behavior
would come from this young upstart.
This was the right moment for the
Tyrannosaurus
. She had been standing
stock-still in the higher, vegetated part of the floodplain, waiting to take advantage
of the chaotic situation and get an easy meal. If she could have felt disappointment,
though, she would have experienced it then as she looked down from her elevated
position and saw both
Triceratops
walking off the floodplain, each very much
alive. She used a mixture of hunting and scavenging to feed her six-ton frame, and
had dined often on
Triceratops
that eventually died from battles with one another.
Whenever she found a dead one, she would take small bites of sweet meat on the
face, and then grab the head shield from the back with her teeth to tear off the head,
exposing its delectable neck muscles. It was tempting for her to follow the limping
onetoseeifhewouldexpire,butattacking toosoonentailed muchrisk.Millions of
years of natural selection had not resulted in one of the world's largest land carni-
vores taking on prey that could also kill it.
Flexible in her menu choices, she turned her gaze toward a nearby group of
hadrosaurs (
Edmontosaurus
) of varying ages that were unknowingly sharing this
grassy-shrubby part of the floodplain with her. Most of these dinosaurs were on all
fours, grazing on the plants around them. But they occasionally reared up on their
hind legs and looked down to their left, having been distracted by the battle be-
low and its effect on the surrounding fauna. As the hadrosaurs pulled up low-lying
plants and chewed, tiny bits of silica in the leaves and stems imparted microscopic
