Our new study reveals a different, often overlooked factor. Daily swings in oxygen levels on the shallow seafloor may have stressed early animals (the ancestors of all animal life today), pushing them ...

Fossils found in Canada suggest animal movement and sexual reproduction began 5 million to 10 million years earlier than ...

For more than 100 years, biologists have wondered why animals display different types of life cycles. Some species, like humans and most vertebrates, develop directly into a fully formed yet smaller ...

A spectacular fossil site in Canada contains 567-million-year-old creatures that may represent some of the earliest animals to move, reproduce sexually, and develop recognizable body plans. The ...

The newly discovered fossil records suggest that mold-like single-cell organisms "set the stage" for the animal kingdom to evolve, the researchers wrote in a new report, published in the journal ...

The transition from aquatic to terrestrial life has been one of the most significant evolutionary challenges. This decisive process in the evolution of life on Earth required a profound renewal of the ...

Kali Holder, a veterinary pathologist at the National Zoo, is motivated by problem-solving and a passionate curiosity about nature. Image: courtesy of Kali Holder When an animal becomes endangered, it ...

If you know anything about the experiences of animals reared in captivity for food, fur or human amusement, you might imagine that the lives of wild animals are idyllic. If nature is conceived as a ...