Ichthyosaurus, the "Fish Lizard,"
was described by Jules Verne as 
"the most terrible of the ancient 
monsters of the deep." However, the
real ichthyosaurus was very 
different from the hundred-foot-long
monster depicted in "Journey to the 
Center of the Earth." These small, 
two-meter-long, torpedo-shaped 
reptiles were rather dolphin-like. 
They moved their tails side-to-side 
like fish, but still breathed air, 
could control their boyancy, and 
gave birth to live young. 

Ichthyosaurus lived from the late
Triassic to the early Jurassic 
Periods across what is now Europe 
and Asia. It was a common sight in
both coastal and open ocean 
habitats, giving it an extremely 
wide range to roam. It was a 
successful carnivore, feeding on 
smaller aquatic reptiles and fish 
with its pointed jaws and sharp, 
conical teeth. Fossils of other 
ichthyosaurs show effects of 
decompression sickness, a condition 
that arises when a creatures goes 
from a high pressure environment to 
a low pressure one too quickly. It 
is likely that ichthyosaurus, like 
its relatives, dove to great depths 
to  hunt and would suffer from the 
same illness if it returned to the 
surface too quickly. Its large eyes 
allowed it to hunt fish by sight, 
even in the low light of great 
depths. 
