Female birds sing. That is one conclusion of our 2020 study on the barn swallow. It highlights a long-standing scientific bias and helps us think about why that bias persists.

Despite the well over 1,000 scientific publications about this species, female barn swallow song had never previously been the focus of a research article. Conventional evolutionary theory assumes that males compete for access to females, leading them to evolve features that help fight off other males or attract females. Birdsongs can function in both these contexts. In fact, females sing in at least 64% of songbird species, and their songs can serve the same functions as male songs.

A second reason for the neglect of female birdsong stems from geographic bias. Any serious birder working in the tropics (热带) could tell you that females do sing. But early researchers tended to study species near their universities in the Northern Hemisphere (半球), where females have lost or reduced their songs, which may represent evolutionary adaptations to conserve energy for migration.

A final reason for female birdsong being understudied could be gender. Men have ruled birdsong research from its start. As more women enter the field, they are much more likely than men to be first authors on papers on female birdsong.

To overcome such biases in the scientific rule, we need to make science more accessible to all. For example, if we can make people aware that female birds sing, we will enhance their experience of nature and improve their ability to observe it.   People who understand the latest science will create better global data sets, which, in turn, will generate better science. Besides, nonscientists make better observers because they lack preconceived (先入为主的) ideas.

Female birds sing! The truth reflects the constant adjustments to the scientific agreements as new facts become available and new voices are added to the conversation. We welcome a future where research, communication and education combine to deepen our connections to one another and the natural world.

Scientists have solved the mystery of why the overwhelming majority of mammoth fossils(化石)are male.

Much like wild elephants today, young male Ice Age mammoths probably travelled around alone and more often got themselves into risky situations where they were swept into rivers, or fell through ice or into mud, lakes or sinkholes that preserved their bones for thousands of years, scientists say.

Females, on the other hand, travelled in groups led by an older matriarch who knew the landscape and directed her group away from danger.

"Without the benefit of living in a herd led by an experienced female, male mammoths had a much higher risk of dying in natural traps such as mud holes, rock cracks and lakes, "said co-author Love Dalen of the Swedish Museum of Natural History in a report published on Thursday in the journal Current Biology.

The study used genetic data to determine the sex of 98 woolly mammoth fossils in Siberia Researchers found that 69% of the samples were male, a heavily unbalanced sex ratio, assuming that the sexes were fairly even at birth.

"We were very surprised because there was no reason to expect a sex bias in the fossil record," said first author Patricia Pecnerova, also of the Swedish Museum of Natural History. Therefore, researchers believe that something about the way they lived influenced the way they died.Most bones, tusks, and teeth from mammoths and other Ice Age animals haven't survived," explained Dalen.

"It is highly likely that the remains that are found in Siberia these days have been preserved because they have been buried, and thus protected from weathering."

These giant, tusked plant eaters disappeared about 4,000 years ago. While there is no scientific agreement about the causes of their disappearance from the planet, most believe that climate change, excessive hunting by humans and the spread of other animals into mammoth feeding grounds were influential factors.

It seems like giant pandas might not be the best at hide-and-seek. With their noticeable black and white coats, they would appear to have a hard time blending (融合) into so many environments. But a new study finds that the symbolic markings help them disappear into their surroundings.

For their study, researchers analysed photos of giant pandas in their natural habitat. They found that the animals are good at visually (视觉上地) hiding in their environments because they use habitats with dark and lighting conditions, and also snow during some of the year.

They found that the black fur blends mainly into shade and dark tree trunks (树干). But it also matches the ground, rocks, and leaves. The white fur matches snow, rocks, and bright leaves. Sometimes pandas also have pale brown fur that blends into rocks, ground, leaves, and shady background areas.

As a last step, the researchers used a color map technique to compare how giant pandas resemble their background with other species that are considered able to visually hide in their environments. They found that pandas fell in the middle of this list.

It might seem a bit confusing because giant pandas are very easy to discover at a zoo. But the viewer and environment make a difference. “We modeled their coloration through predators’(捕食者的) eyes as well as how humans see them so we are sure of the results,“ study author Tim Caro of the University of Bristol says. ”It seems that giant pandas appear eye-catching to us because of short viewing distances and specific backgrounds: when we see them, either in photographs or at the zoo, it is almost always from close up, and often against a background that doesn’t reflect their natural habitat,“ says author Nick Scott—Samuel of the University of Bristol.