Herbivorous Dinosaur Diets

Drawings coming in an hour or so...still drawing three of them right now......

Dinosaurs ate grass!  This is a rather new discovery since for years we have thought that grass did not evolve until the very end of the Cretaceous Period or the  beginning of the Tertiary Period...around 65 million years ago or so.  But this is now old science because when new discoveries change so does the science!  Fairly new research has determined that grass was around 125 million years ago.   This was detremined by studying dinosaur coprolite.  Coporlite is fossilized dung.  It was discovered that Titanosaur dung, from India had evidence of 5 different species of grass.  This means that grass had not only already evolved, but it had started to diversify into several different species.

There was also evidence of broadleaf flowering plants in the dung, along with conifers  and palms.   So this Titanosaur ate lots of different things including grass.  Grass was not the majority of its diet but it was there.

Bruhathkayosaurus Feeding on Palm Leaves

So this drawing is of the Indian Titanosaur, Bruhathkayosaurs, that is very controversial.  It was identified by a tibia (lower leg bone) and a partial vertebrae.  But those fossilized bones were lost in monsoon flooding.  Bruhathkayosaurus may have been as heavy as 242.5 tons or 220 metric tonnes...and as long as 144 feet or 44 meters.   These estimates are very controversial and since the fossilized bones are lost the species existence is subject to doubt by most in the scientific community.  Because of this many paleontologists give the title of biggest dinosaur to Patagotitan.  We have over 200 fossilized bones of Patagotitan and they are of 6 different individual dinosaurs.  In the above drawing notice that Bruhathkayosaurus would have probably been taller than the trees so it may have had to lower its head to browse on palm leaves.  Remember that it also would have grazed on grass sometimes as well.

In any case, if Bruhathkayosaurus was the source of the fossilized dung or coprolite mentioned in the first paragraph then it was clearly eating palm tree fronds, conifer needles, and 5 kinds of grass.
So later dinosaurs, like the duckbill dinosaurs called Hadrosaurs may also have eaten grass.  Animals that ate or eat grass are called grazers.  Horses are also grazers.

The Hadrosaur Corythosaurus Eating Grasses

So far scientists have found that duckbilled dino coprolites contain shrub or tree leaves and surprisingly, wood.  So like mule deer, they may have eaten bark off of trees or even chewed on rotting branches.  So, dinosaurs also ate wood!   Well, at least some of them did.  Animals that ate or eat shrubs and tree leaves are called browsers.  Deer are also browsers.

Maiasaura feeding on Wood

So apparently some dinosaurs were both browsers and grazers.  The discovery of grass' appearance at a much earlier date than previously thought tells us that maybe many dinosaurs of the Jurassic and Cretaceous Periods were both browsers and grazers.  It was previously thought that Ceratopsian dinosaurs were just browsers but this new evidence points to these horned dinosaurs also being grazers.  

Triceratops Grazing