Final answer:
Yale and Princeton played in the first Thanksgiving Day football game in 1876. The sport at that time was rough and similar to rugby, with the forward pass and other rules not yet established, leading to a game with little protection and a high injury rate.
Step-by-step explanation:
The college teams that played in the first Thanksgiving Day football game were Yale and Princeton in 1876. The game took place as a result of the evolution of college football from informal matches played by student clubs in the 1870s, where student-athletes essentially self-regulated and played by ever-changing rules, to more organized college football rivalries.
By the time college football had reached the 1890s, it had become a major topic of conversation and had grown in popularity, rivaled only by professional baseball. The introduction of the forward pass and other rules in the early 1900s helped to evolve the game into a sport with fewer injuries and a higher speed of play. However, the initial organized collegiate football games, such as the one on Thanksgiving, were much rougher, resembling a mixture of rugby and boxing without protective clothing.