Chad's animal and plant life correspond to the three climatic zones. In the Saharan region, the only flora is the date-palm groves of the oasis. Palms and acacia trees grow in the Sahelian region. The southern, or Sudanic, zone consists of broad grasslands or prairies suitable for grazing. As of 2002, there were at least 134 species of mammals, 509 species of birds (354 species of residents and 155 migrants), and over 1,600 species of plants throughout the country.