system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How are we able to find dinosaur bones from millions of years ago when there have been millions of other animals dying and leaving their bones behind?

Shouldn't there just be so many bones that we couldn't even find any dinosaur bones left? I feel like there should be soooo many bones everywhere.
gpt
Your question has kind of an incorrect premise because it sounds like you're assuming all of the bones should be mixed together.  The age of the fossils you find depends on the rock that they're embedded in.  The reason we know fossils that we dig up are dinosaur fossils, or pre-dinosaur fossils, or post-dinosaur fossils is because we know the ages of the rocks that we're pulling them out of.  Something that comes out of a rock that is 5 million years old is not a dinosaur fossil.  Something that comes out of a rock that 90 million years old probably is.

Edit:  Also, the reason there aren't soooooo many bones everywhere is because fossilization is actually very rare, most animals just rot and decompose when they die, they only fossilize under very particular conditions.