There are still tons of questions researchers aren’t able to figure out about dinosaurs, even with Erickson’s new methods. For instance, it’s impossible to determine the sex of dinosaurs just from looking at their skeletons.
There have been plenty of theories, but they just haven’t panned out. Erickson himself has done plenty of studies with what a lot of people consider to be living dinosaurs – alligators – that have resulted in theories being proven incorrect. “That’s one of the biggest mysteries – not knowing the sex of an animal.”
Erickson has also said that dinosaurs likely took a long time to mature, even after they'd hatched. Such slow-developing creatures weren't well-equipped to take on the challenges of the post-asteroid world, and couldn't adapt in time to last.
Adjusting to change and adapting is a critical skill for all species (even humans!) and being unable to do that after such a dramatic change to the planet may have spelled the death of dinosaurs as we know them.
“The dinosaurs found themselves holding some bad cards,” Erickson told The New York Times in 2017. “They had a dead man's hand.”
Dinosaurs like the Hypacrosaurus and the Protoceratops disappeared long after the mass extinction happened, but they are being researched until this very day.
Another big question is – how did dinosaurs get so big? Even compared to larger creatures that are around now, such as elephants or giraffes, dinosaurs were huge – even the herbivores. Plenty of them would tower over humans and most other animals.
Even the largest species of animal we have today – the blue whale – only just reaches the size of some of the larger dinosaurs, and the blue whale has the benefit of being an underwater creature, something that facilitates bigger sizes.
One of the most important questions to this day is why dinosaurs aren't around anymore. We have plenty of information about possible reasons, but right now it's little more than a jumbled mass of intersecting theories, ideas, and thoughts.
In an interview for Earth magazine, Erickson has said: “I've spent my career trying to figure out anything I can learn from bones and teeth, and what they can tell you about biology. I always try to find something in a modern animal that I can use in paleontology, like the replacement rates for teeth or how they grew from growth lines in their bones.”