http://www.angryalien.com/aa/jurassicbuns.asp

I’ve watched scrub jays running around on my lawn, eating bugs, looking exactly like little dinosaurs.

Or like a pigeon with it's head motion while walking.

My chickens run around very similar to the run we see of T-Rex/raptors in movies. They lean forward and low and run surprisingly fast for an animal with wings that they just tuck.

Have you ever seen a real roadrunner?

quakey

Skull weight alone would make hopping difficult. Their heads are huge.

first off AFAIK they don't even have anything near the amount of muscle in the right places to try hopping, but even if they did manage it i'm pretty sure their legs would snap in half when they landed and then as the rest of the body met the ground they'd crack ribs and stuff as well.

Imagine trying to jump around while wearing a dishwasher on your back, even if you're monstrously strong in every part of your body it's gonna fucking suuuuuuuuck

Footprints.

https://www.popularmechanics.com/science/animals/a10933/tyrannosaurus-trackways-reveal-a-dinosaurs-walk-17016027/

Kangaroos hop because they can store a lot of energy in there Achilles tendon and use that to propel them forward without using much energy. It's good for covering long distances over flat terrain while using as little energy as possible , which is good for the Australian outback as they hop between small patches of vegitation separated by miles of desert. It's not that good for ambushing or quickly chasing prey in a rainforest like the t rex is probably doing.

There's also the issue of scale, a t rex's Achilles tendon would have to be stronger then steel cable and as stretchy as rubber to store and re use that much kinetic force from its weight.

Likely footprint patterns

Most likely the weight difference would be the biggest issue here.

Same reason why to scale bug wings wouldn't let you fly, that square cube law can lead to some very unfun conclusions where big beasties are concerned.

Or some absolutely terrifying ones in Shin Godzilla's case.

Probably something to do with strain on the body. Studies show T. rex couldn't even run. Maybe a fast walk. Additionally, the way the muscles attach to the bones probably don't support hopping.

T Rex only known organism to lick its way to the center of a Tootsie pop

"Nurse said that if I were a good lad that I should receive a lolly!"

Mass per volume is density, and I suspect the Trex and kangaroo are similar (~1000 kg/m^3) so yes they'd both bounce in that case. I think what you're looking for is surface area to volume, which decreases rapidly as an object gets larger while maintaining geometry.