Spinosaurus quickly smashed its way to the top (literally!) following the success of Jurassic Park III. At up to 56 feet (17 meters) in length,
Spinosaurus (found in
Egypt and
Morocco) is unquestionably the longest carnivorous dinosaur that has ever been discovered, and by a significant margin, too. But how could
Spinosaurus be so successful when another carnivorous monstrosity,
Carcharodontosaurus, lived in such close proximity? The answer lies in what it ate; in fact,
Spinosaurus appears not to have been as carnivorous as we once thought, and seems to in fact have been more
piscivorous. Essentially, it is thought that
Spinosaurus might have survived on a diet consisting a great deal upon fish.
There is a great wealth of information that indicates the staple diet of
Spinosaurus was
fish. Here we will take a more in-depth look at this evidence.
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| A picture of Spinosaurus drawn by the talented young artist Sam Lippincott. |
1. POSITION OF THE NOSTRILS:
Spinosaurus, unlike most other theropod (meat-eating)
dinosaurs had nostrils situated very high up on its skull. By contrast, most other theropods, like
Tyrannosaurus, had nostrils very close to the front of the skull. The nostril placement in
Spinosaurus would have allowed it to stick its nose into the water quite deep, enabling it to hunt fish more effectively.
2. SENSORY ORGANS ON THE TIP OF THE SNOUT: Along with the high placement of the nostrils,
Spinosaurus also had a number of small sensory organs at the front of the snout, revealed by CT scans. These greatly resemble those of the
crocodile, who uses them to sense where prey is by "seeing" tiny movements in the water. Thus, a crocodile can attack its prey without ever seeing them with their eyes.
Spinosaurus appears to have been able to do much the same thing, making its hunting method of choice quite obviously effective, given its immense size.
3. ISOTOPIC EVIDENCE: A study of the isotopes in the skull of a
Spinosaurus specimen revealed something quite interesting.
Spinosaurus shares a great deal of isotopic overlap with crocodiles, fairly aquatic animals. By contrast, other carnivorous dinosaurs like
Tyrannosaurus have very different isotopic readings, indicating a terrestrial lifestyle. Given the great deal of overlap possessed by
Spinosaurus and crocodiles, it appears that
Spinosaurus spent much of its life like a crocodile; semi-submerged in rivers and streams.
4. THE TEETH TELL THE TALE:
Spinosaurus, unlike most other carnivorous dinosaurs like
Tyrannosaurus, Allosaurus, or the famous
Velociraptor, possess conical, round teeth. These other carnivores possess thin, blade-like teeth, made for slicing, crushing or tearing into other animals.
Spinosaurus has
teeth much like a crocodile; round and conical. These teeth are made for gripping and making sure that an animal does not escape.
5. THE TEETH TELL THE TALE....AGAIN: Yet again, we come to the issue of teeth, and this is one of the most damning pieces of evidence of all. During the time that
Spinosaurus lived in North
Africa, another inhabitant of these streams and rivers was a saw-toothed fish called
Onchopristis. Two fossils involving
Onchopristis have been discovered in conjunction with the remains of
Spinosaurus. One was the skull of a
Spinosaurus; imbedded in one of the tooth sockets was a vertebrae from an
Onchopristis. The other discovery was the barb of an
Onchopristis embedded in the jaw of the
Spinosaurus.
6. PLUS: We only ever seem to find
Spinosaurus in shallow aquatic environments, where fishy prey would be abundant.
All in all, it seems like an inevitable conclusion to draw that
Spinosaurus was, in fact, a piscivore, at least much of the time. A fascinating example of the crazy turns evolution can take.