[1] In his early 20s on the recommendation of his mentor, Auguste Pyrame De Candolle, he joined a Mexican scientific expedition as a biologist and plant specialist.
In the fall of 1828, with a group of 30 Mexican soldiers led by Colonel José Francisco Ruiz, Berlandier accompanied Comanche leaders Reyuna and El Ronca on a bear and American Bison hunt on open lands northwest of San Antonio.
Berlandier's extensive knowledge of the region of south Texas and Tamaulipas, garnered from his field explorations to collect botanical specimens, was invaluable to General Arista.
After the Treaty of Guadalupe Hidalgo ended the fighting in February 1848, Berlandier was asked in 1850 to take part in the International Boundary Commission to define the border between Mexico and the United States.
[2] Berlandier's manuscripts contain the only existing records of some languages of the Lower Rio Grande Valley, including Mamulique and Garza.