The Google Chrome Dinosaur Game

On occasion, my home Internet router will reboot itself for reasons unknown to myself, and during one such instance recently, I was left realizing how much that I rely on the Internet these days and was unable to do much without it. However, since I use the Google Chrome browser, I was able to play the jumping T. rex game while waiting for my router to finish rebooting (press arrow keys on the "No Internet" screen to activate). While trying to beat my high score, I noticed that the dinosaur, some kind of tyrannosaurid (the T. rex family), was jumping over saguaro cacti. This got me wondering about the evolution of cactus plants and when they evolved. Cactus are flowering plants (aka angiosperms) and angiosperms evolved in the late Jurassic Period, and rapidly diversified during the Cretaceous Period. But, did the cactus (particularly saguaro) live at the same time as the dinosaurs?

First, when did cacti evolve? Interestingly,“[t]here are no relevant fossil records for cacti or their closest relatives, which has made it difficult to estimate divergence times in the group” ¹. According to this study, divergence of the cactus group of plants may have happened approximately 35 million years ago (Ma), and major cactus diversification was around 5 to 10 Ma. So, dinosaurs and cacti did not co-exist, at least according to what we know about cactus evolution, which is surprisingly sparse.

Although, the dinosaurs didn't get pricked by cacti, there were big things with big teeth to worry about.

credit: The Field Museum, painting by John Gurche

So, the timing doesn’t work out. What about locations? Where did the cactus originate and did it live in the same places as the T. rex? According to the University of Arkansas Agriculture Extension Office, no cactus plants are known from Africa, but they are found in the Americas. Thus, it can be reasoned that cacti originated after the breakup of Pangea (unless they went extinct in other localities and left no fossils). Cacti appears to have originated in South America, possibly related to the Andean uplift, and migrated into North America. While the saguaro cactus is native to the southwest, the T. rex was native to areas further north. As far as I am aware, the T. rex is known only to the area that encompasses Colorado to Montana to the Dakotas, and to Canada, but relatives have been found further south in the Arizona-New Mexico area. At the time of T. rex, these areas were humid, tropical to sub-tropical environments covered by forests, swamps, and rivers. Much different from the arid, dusty environment that exists today.

So, although the saguaro cactus lives on the same continent as the T. rex, it appears that they missed each other by about 30 to 60 million years and possibly by a few hundred miles. If only Google would have hired a paleontologist, they could have made a more prehistorically accurate game. Perhaps palm trees would have been more accurate. But, I’ll give them a pass this time, since the game stars a dinosaur.