The short-faced bears turned out to be remarkably adaptable, undergoing radical changes to meet the demands of two changing continents. And yet, for reasons we don’t quite understand, their adaptability wasn’t enough to keep them from...

As revolutionary as teeth were, they would go on to disappear in some groups of vertebrates. But why?

This live-action video program is about the word biome. The program is designed to reinforce and support a student's comprehension and retention of the word biome through use of video footage, photographs, diagrams and colorful, animated...

This live-action video program is about the word biome. The program is designed to reinforce and support a student's comprehension and retention of the word biome through use of video footage, photographs, diagrams and colorful, animated...

B/W 1936 long shot wide shot horse standing on plain / Dust Bowl / USA

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

a wild cockroach is moving its antenna on the plant leaf

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

The annual Great Migration of wildebeest and other grazing herbivores across the Serengeti-Mara ecosystem is one of the greatest spectacles in the natural world. About 200 000 zebra and 500 000 Thomson's gazelle ...and one-and-a-half...

MS Herd of African buffalo walking in savanna / National Park, Africa, Kenya

HD1080p: WIDE ANGLE shot of a herd of zebras in the African savannah. Namibia. Africa.