Several new species of tropical birds have been found on remote islands in Indonesia. Researchers have discerned the Wakatobi sunbird, a new species that lives on the small Wakatobi Islands, located in central Indonesia. They also studied olive-backed (橄榄背的) sunbirds and black sunbirds and found that some of the birds they examined actually belonged to some previously unrecognized species.

The new Wakatobi sunbird looks similar to the olive-backed sunbird, but has darker feathers, shorter wings, and a higher-toned song. Zoologists believe that because it has such short wings, it never spread beyond the tiny islands. The olive-backed sunbird, however, can fly long distances, so it was able to inhabit other locations.

These discoveries were part of a long-time cooperation between scientists at Trinity College Dublin and Universitas Halu Oleo in Sulawesi, Indonesia.

“Specifically, we became interested in the Wakatobi sunbird because of the work of Ernst Hartert, a German bird expert active at the beginning of the 20^th century,” Fionn O Marcaigh, first author on the paper, says. “He described the Wakatobi sunbird as a population with distinctive dark feathers, but he and the rest of the scientific community eventually decided that it was only a subspecies of the widespread olive-backed sunbird. We were eager to use modern methods to put this to the test.”

For their research, scientists used DNA, recordings of songs and body measurement analysis to compare the sunbirds they studied, “We used a system called integrative taxonomy, which combines data on a number of aspects of the birds, including their songs, feathers, and body structures,” O Marcaigh says. “We recorded their songs using digital recorders, measured live birds caught and released by licensed netters, and used computational statistics to analyze the differences.” The scientists also obtained genetic samples which they analyzed in the lab and they found that the patterns they found were also reflected in the birds’ DNA.

“I’m excited that we’ve added to the list of known species from this wonderful part of the world,” O Marcaigh says.

Humans spend about one third of their lives sleeping. But some mammals (哺乳动物), like the northern elephant seal, survive with much less sleep.

Researchers in a new study described the unusual sleep pattern of these ocean animals. They found that when these mammals go to feed on trips that can last seven months, they sleep just two hours each day. Those two hours of sleep are made up of short moments of rest lasting only 10 minutes each as they dive deep to avoid predators (捕食者). The only other mammals known to get so little sleep are African elephants.

The researchers placed a head covering with sensors (传感器) on the heads of the seals that they studied. The sensors recorded sleep signals created by the seals’ brains and heart rate. The sensors also recorded the animals’ location and depth beneath the sea. Female seals go out on longer open-ocean trips while males only feed in coastal waters. Because of this, the researchers only studied female seals.

During dives lasting about 30 minutes, the seals went into a deep sleep called slow-wave sleep while keeping a controlled downward movement. When they then experienced rapid-eye-movement (REM) sleep, the seals fell into a turning pattern. Then, at the deepest point of their sleeping dive—up to 377 meters deep—they wake up and swim back to the surface.

Terrie Williams is a scientist at the University of California at Santa Cruz who helped write the study. She said, “It is remarkable that a wild animal will fall into deep, paralytic REM sleep when there are predators on the hunt.” She added that the seals solve this problem by going into deep sleep in the deep parts of the oceans where predators usually do not hunt them.

Williams said the brain’s ability to control awakening the sleeping seals at a depth before they drown is also a discovery about how mammalian brains work. She commented on this, saying that it shows the survival control of the seals’ brains.