The bottomland habitat contains mature cottonwoods and tallgrass prairie species such as big and little bluestem, and indiangrass. This area offers a home to many species of native wildlife, and provides for a variety of wildlife dependent recreational opportunities.
The refuge provides an island of prime habitat for resident species such as white-tailed deer, coyotes, Rio Grande turkeys, quail, and many others. Because of its important habitats, Optima National Wildlife Refuge is a migratory stopover and summer home to many species of songbirds and raptors.
Raptors are common year-round. During the spring and summer months, common species include the Swainson's hawk, Mississippi kite, American kestrel, red-tailed hawk, northern harrier, and turkey vulture. Species common in the fall and winter months are bald and golden eagles, prairie falcon, rough-legged hawk, Cooper's hawk, and ferruginous hawk. Resident game birds include the Rio Grande wild turkey, ring-necked pheasant, bobwhite quail, and scaled quail.
A variety of mammals are also found on the refuge, including mule deer, bobcat, porcupine, black-tailed jackrabbit, badger, raccoon, and striped skunk. Reptiles include the prairie rattlesnake and the Texas horned lizard, commonly called the horned toad.