Source: Brenham Weekly Banner – January 14, 1886, p. 3
This except from an 1886 article by Moses Austin Bryan about his early days in Texas says a lot in one sentence:
When I first came to Texas, in 1831, what is now Washington county, was roamed over by buffalo, mustangs, (wild horses,) deer by the thousands, leopard cats, wolves, Mexican hogs and wild cattle.
This puts ocelots, bison and longhorns (wild cattle) in east central Texas in the early 19th century. It also alludes to the numbers of deer, which had been reported to congregate in large herds by other explorers.