How a helpless baby bird protects itself from hungry hunters

There’s not a more vulnerable creature in nature than a baby bird. Tiny and immobile, they’re easy pickings for predators. But the chicks of the white-necked jacobin hummingbird have evolved a unique defence. They disguise themselves as poisonous caterpillars to discourage those that might eat them. Jay Falk, an NSF postdoctoral fellow at the University of Colorado and Scott Taylor, director of the Mountain Research Station and associate professor at the University of Colorado, studied these birds in Panama. Their research was published in the journal Ecology.

Seals have a sense of their oxygen levels, which makes them better divers

Seals can dive at length to tremendous depth thanks to some remarkable adaptations, like the ability to collapse their lungs, and radically lower their heart rate. Chris McKnight, a senior research fellow at the University of St Andrews Sea Mammal Research Unit in Scotland, led a study looking to see if tweaking oxygen and C02 levels changed the seals’ dive times. The researchers discovered that the seals have the unique ability to measure the oxygen levels in their tissues, so they can anticipate when they need to return to the surface before they get into trouble. The research was published in the journal Science.

Fruit flies can show a playful side

As the joke goes, time flies like an arrow, fruit flies like a banana. Researchers recently demonstrated that fruit flies enjoy more than just aged produce. Using a custom carousel built to fly scale, scientists found that some, but not all, of their fruit flies would play on it, enjoying an activity that had nothing to do with the necessities of life. This brings up the possibility of variability in personality for fruit flies. Wolf Hütteroth is an associate professor at Northumbria University, Newcastle and was part of the team, whose research was published in the journal Current Biology.

Scaring krill with a dose of penguin poo

Krill, the small, shrimp-like creatures that swarm the world’s oceans and are particularly abundant in southern oceans, play a big role in marine food webs, connecting microscopic organisms with many of the oceans’ larger animal species. Researchers in Australia investigated how krill respond to predator cues, like the smell of their feces. Nicole Hellessey, from the University of Tasmania, said the mere whiff of penguin feces affects the Antarctic krills’ feeding behaviour and causes them to take frantic evasive action. The study is published in the journal Frontiers in Marine Science.

Fossils tell us what dinosaurs were. How do we know what they did?

Dinosaur bones can tell amazing stories about these prehistoric beasts, but how do we piece together how they behaved? A new book dives into the many lines of evidence that can shed light on the behaviour of these extinct creatures. From fossils, to tracks they left behind, to their modern day descendents, paleontologist David Hone from Queen Mary University of London explores how scientists develop robust theories about how dinosaurs lived in his new book, Uncovering Dinosaur Behavior: What They Did and How We Know.

A tree has evolved to attract lightning strikes — to eliminate the competition

Scientists working in Panama noticed that a particular tropical tree species was frequently struck by lightning, but was infrequently killed by the strikes. Forest ecologist Evan Gora found that Dipteryx oleifera trees were often the last ones standing after a lightning strike, which can kill over 100 trees with a single bolt. His team discovered the giant trees were more electrically conductive than other species, which allows them to not only survive strikes, but also channel lightning into parasitic vines and competing trees around them. The research was published in the journal New Phytologist.

Anti-anxiety drugs we pee out could be affecting wild salmon

Our bodies only process some of the pharmaceuticals we take, which means when we pee, we’re releasing traces of drugs into the ecosystem. A study of the impact of trace amounts of anti-anxiety drugs on juvenile salmon suggests they might become too brave for their own survival. Jack Brand is a researcher at the Swedish University of Agricultural Sciences and led the research published in the journal Science.

Fossil discovery gives new insight into the mysterious Denisovans

A jawbone pulled up by fishers off the coast of Taiwan in 2008 has proven to be a unique discovery. Analysis of preserved protein in the fossil has proved it is from a male Denisovan — a mysterious species of ancient human known from only fragmentary bones and ancient DNA. This gives new insight into how widespread this mysterious branch of humanity was. The research was led by a team including Takumi Tsutaya and Enrico Cappellini at the University of Copenhagen, and published in the journal Science.

Earth’s inner core is a lot more dynamic and smushy than we previously thought

Scientists used to think the inner core of our planet was a solid sphere of metal, but a new study in Nature Geoscience suggests its softer outer layers shift and deform over time. The researchers used pairs of earthquakes from the same location as X-rays to peer inside Earth to gauge what the inner core is doing; much like a stop-motion film. John Vidale, from the University of Southern California, said this insight can shed light on how a planet like ours evolves.

Human noise has an impact on wildlife — here are two unique examples

Traffic, aircraft, industry, construction. Our world is saturated with artificial noise. We know noise impacts us and other animals, but new research is shedding light on how past experiences factor into the ways wildlife adapt to our noise pollution.

Researchers in one study in Animal Behaviour found that yellow warblers in the Galapagos Islands that live closer to traffic become aggressive when defending their territory in noisy conditions compared to birds in quieter areas. Çağlar Akçay, from Anglia Ruskin University, said the birds exposed to more traffic have learned their warning calls aren’t as effective when things get too noisy; and they resort to physical violence.

Another study in Current Biology shows how spiders that are exposed to loud noises construct their webs differently in ways that could affect their ability to sense vibrations from prey or a potential mate. Brandi Pessman, from the University of Nebraska-Lincoln, found that spiders tune their webs in noisy environments like a volume dial: city spiders turn their web volume down whereas country spiders turn it up.

An attractive new strategy for brain surgery

A Canadian team is developing minimally-invasive micro-tools for brain surgery that can be operated by magnetic fields from outside of the skull. The tools, including scalpels and forceps, will enter the cranium through small incisions, and then be controlled by focused and precise magnetic fields. Eric Diller is associate professor of mechanical and industrial engineering at the University of Toronto and his research was published in the journal Science Robotics.

Animal tool use is fishy

In recent decades scientists have discovered animals from primates to birds and marine mammals can use tools — a capacity once thought to be exclusive to humans. Now scientists have discovered fish using hard surfaces to crack open hard-shelled prey and get at the meaty meal inside. The research, led by Juliette Tariel-Adam from Macquarie University, included recruiting divers and scientists from around the world to report any sightings of tool use, which led to 16 reports across five species of wrasses. The results were published in the journal Coral Reefs.

Bad news — a long cold bath may be good for you

For a hardy few, soaking in cold water has long been held out as being healthful and invigorating. Well, unfortunately, the latest research suggests that they’re right. Volunteers who soaked in cold water for an hour a day for a week showed improvements in autophagy, an important cellular clean-up function that typically declines with age. Kelli King is a postdoctoral researcher at the University of Ottawa and was co-lead on this study, published in the journal Advanced Biology.

How the unicorn of the sea uses its horn

The Narwhal is a small whale distinguished by its long spiral horn — an elongated tooth. Researchers have long speculated about what the ostentatious bit of dentition is actually for, but the elusive narwhal has, until now, been hard to study. Now scientists, including Cortney Watt from Fisheries and Oceans Canada, have used drones to learn that the horn is used in several ways: to play, explore, and forage. The research was published in the journal Frontiers in Marine Science.

Why your body and brain might be fighting your efforts to get and stay slimmer

New research is revealing why it’s so difficult to keep weight off after you’ve lost it.

One study in Nature found that genes in the fat cells of people who lost a significant amount of weight through bariatric surgery largely continued to behave as if they were still obese. Ferdinand von Meyenn, from ETH Zurich, said that despite these individuals becoming, in many respects, much more healthy, genes that became active during obesity remained active, and genes that were turned off, remained turned off, predisposing them to regain lost weight. In formerly obese mice, their fat cells remained much better at taking up sugars and fats.

In addition, another study revealed that neurons in a primitive part of the brain hold onto memories of fat and sugar that can drive our cravings, according to a study on mice in Nature Metabolism. Guillaume de Lartigue, from the Monell Chemical Senses Center and the University of Pennsylvania, said specific neural circuits in the brain light up, depending on whether the gut received sugar or fat. Removing these neurons protected the mice from diet-induced weight gain, something de Lartigue is hoping to translate to humans to dial down impulsive eating behaviour.