Miocene landscapes were not one continuous modern savanna. Between about 23 and 5.3 million years ago, climate, rainfall and vegetation differed across continents and shifted through time. In some regions, woodland became more open and grass-rich habitats expanded. These changes created new opportunities for grazing mammals and for predators that followed them.
Quick facts
| Epoch | Miocene, about 23 to 5.3 million years ago |
|---|---|
| Habitats | Woodland, grassland, wetlands and seasonal open country |
| Herbivores | Equids, antelope-like bovids, giraffoids and rhinoceroses |
| Predators | Different mammal and bird lineages on different continents |
| Evidence | Fossils, teeth, sediments and plant remains |
How do fossils reveal a savanna?
Fossils of animals are interpreted alongside the rocks, pollen, plant fossils and soil features from the same layers. Tooth shape and microscopic wear can help distinguish browsing from grazing, while isotope values can preserve clues about diet and water. A single animal fossil does not establish a savanna, and species from different continents or ages should not be assembled into one real community.
Opening habitats and new grazers
Where grasses and other open-country plants became more abundant, herbivores with long limbs and durable teeth could exploit a different food supply from animals feeding mainly on leaves in dense woodland. Three-toed horses and other equids are part of this story. Their teeth and foot bones changed across multiple lineages, and a fossil called a “horse” in a broad popular account may not be a direct ancestor of living horses.
Antelope-like bovids and early giraffoids also diversified during the Miocene. Some had longer limbs that helped them move through open terrain; feeding height and tooth structure varied among groups. Rhinoceroses and other large herbivores occupied several environments, including woodland and wet ground, so the period cannot be reduced to one grassland fauna.
Predators followed different histories
As herbivore communities changed, so did their predators. Amphicyonids, often called bear-dogs, were a diverse group of carnivorous mammals with body plans unlike those of modern dogs or bears. Sabre-toothed cats and other carnivores also occupied Miocene ecosystems. Their fossils are found in particular regions and formations, not everywhere that antelope-like herbivores lived.
South America had its own history. Large flightless phorusrhacid birds, sometimes called terror birds, evolved there and persisted through much of the Cenozoic. They are an example of a regional predator lineage, not members of the same African community as every Miocene antelope or giraffoid. Continental separation shaped which animals could meet and which ecosystems developed.
A changing world rather than a single scene
Miocene ecosystems were experiments in different combinations of plants, herbivores and predators. The balance between forest and open ground varied with latitude, rainfall and local geology. Some lineages later disappeared, while others left descendants that are part of modern mammal groups. The Neogene Period guide places the Miocene between the older Paleogene and the later Pliocene. The history of horses offers one example of how mammal anatomy changed within this broader environmental story.
Frequently asked questions
When was the Miocene?
The Miocene lasted from about 23 million to 5.3 million years ago and is part of the Neogene Period.
Were Miocene savannas like those of modern Africa?
Some Miocene regions had open grass-rich habitats, but vegetation and animal communities varied by continent, climate and time.
What evidence shows that an animal grazed?
Researchers combine tooth shape and wear with fossils of plants, soils, sediments and, where preserved, chemical signals in teeth.
Did all Miocene predators hunt the same prey?
No. Predator groups lived in different regions and ecosystems. Fossils from separate continents should not be treated as one shared community.