While the dinosaurs became reportedly extinct over 65 million years ago, most of our modern animals have only evolved in the past 50 million years. The question then arises were any of the the ancestors of animals existing today alive when the dinosaurs ruled the planet? Do they still look the same? If so, what were they and how did they survive whatever ended the era of the dinosaurs?
For starters, there are the insects, and insects are animals! The cockroach has been on the planet for over 300 million years and, aside from being a bit smaller in many cases, is the same now as it was then! Then there are ants, beetle species, bees, butterflies, moths and even dragonflies (of course, some of the dragonflies were over 12 inches across the wings)! One can also not forget those mosquitoes that the scientists used in Jurassic Park for cloning the dinosaurs. Insects were around at the time of the dinosaurs and many look just like they do today.
Archaeopteryx is generally considered the first bird (though some claim it was actually a flying dinosaur with feathers) and first appeared around 150 million years ago. This means that something like birds was definitely around during the time of the dinosaurs. Were any the ancestors of real birds that exist today? No one really knows for sure, and many consider birds to be the descendants of the dinosaurs.
Some of the numerous reptiles lived at the same time as the dinosaurs. Crocodiles, sea turtles, land tortoises, and even snakes are almost as old as that cockroach! In many cases the creatures are now smaller, but not always small. Some sea turtles can weigh well over 2500 lbs and crocodiles get over 20 feet long, not to mention those giant anacondas up to 70 feet or more, they do actually exist and eat can goats and even the occasional human!
And there were mammals during the time of the dinosaurs! Most were small rodent-like creatures, similar to shrews, rats and mice. There were also marsupials such as opossums, that's why they are found on just about every continent! They were eating the insects and possibly gnawing a few dinosaur bones for extra calcium. There was also predecessors of the platypus, spiny anteater and even hedgehogs. Just reported on the news was a skeleton of a large primate 47 million years old, three feet tall at an estimated 9 months of age, still a juvenile and growing, did its ancestors live at the time of the dinosaurs? Possibly.
Many marine species that are still found in the oceans today inhabited the planet during the time of the dinosaurs, though maybe not actually living alongside the dinosaurs. These include jellyfish, gars, sturgeons and sharks to name a few. There was also the famous coelacanth rediscovered off the coast of Africa, its ancestors first tried exploring the land and later possibly became dinosaurs! According to paleontologists, the coelacanth is still the same as it was 300 million years ago.
How did any of these creatures survive the cataclysm that destroyed the dinosaurs and avoid dying out? They survived by being smaller, requiring less food, and having ways of storing energy to keep warm better than their larger neighbours. It is a good thing that they did, or we might not have them around to appreciate today. Of course, maybe some of the insects such as those pesky mosquitoes should have joined the dinosaurs on the way to extinction!