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Body battery

Engineers from the University of Colorado, Boulder, US, have created a wearable device that can draw electricity from the human body.

The device, described in the journal Science Advances, is made from a combination of thermoelectric chips, liquid metal as wiring and a variety of carbon-based polymers. It can convert heat from the body into electrical power.

There’s a catch: the device only generates 1 volt per square centimetre of covered skin, so it won’t be charging your car any time soon. But it could be useful for running things like watches and fitness trackers.

It’s also stretchy and self-healing, and fully recyclable – making it a lot more environmentally conscious than ordinary batteries.

“Whenever you use a battery, you’re depleting that battery and will, eventually, need to replace it,” says Jianlang Xiao, senior author on the paper. “The nice thing about our thermoelectric device is that you can wear it, and it provides you with constant power.”

The team has previously made a few other wearable-tech devices, including electronic skin that looks like human skin.

Xiao thinks that these devices could make it to market in the next five to 10 years, after they work out the last few kinks in the design.

Bat adoption

Did you know vampire bats will occasionally adopt bat orphans and raise them on their own? This process was caught on camera during a recent study on captive vampire bats in Panama.

The researchers were examining the way vampire bats form social bonds, using individuals captured in different locations.

Two of the females, named Lilith and BD, formed a close social bond in captivity despite never having met before. They shared food and groomed one another. When Lilith died, BD took over the care and feeding of her pup.

Surprisingly, even though she didn’t have a pup of her own, BD was also able to nurse the pup. “Shortly before Lilith died, I noticed that the pup would occasionally climb onto BD, and I suppose this may have initiated a cascade of neuroendocrine mechanisms that caused BD to start lactating,” says Imran Razik, the study’s lead researcher.

La Niña peaking

The 2020–21 La Niña event peaked in October, according to a report from the World Meteorological Organisation. Released last week, the report suggests a high likelihood of a return to neutral El Niño Southern Oscillation conditions by April–June.

La Niña is a large-scale meteorological phenomenon driven by the cooling and shifting of ocean currents in the Pacific Ocean. In eastern and central Australia, it’s linked to more storms and higher rainfall. The reverse condition, El Niño, often happens alongside drought. 

While La Niña has a global cooling effect, 2020 was still one of the top three hottest years on record thanks to climate change.

Detailed dog genetics

Humanity’s love for dogs meant that the genome of Canis familiaris was one of the first to be fully sequenced, in the early 2000s. But the genome is composed of tens of thousands of genes, leaving a lot of space for gaps and inaccuracies, and we’ve learned a lot more in the years since.

A new paper published in Communications Biology fills a lot of these gaps with a new and improved dog reference genome. According to the authors, the old genome had 23,000 gaps. The new genome, sequenced from a German Shepherd named Mischka, has just 585. 

“We can think of the genome as a book,” says Jennifer Meadows, the study lead author. “In the previous assembly, many words and sometimes whole sentences were in the wrong order or even missing. Long-read technology allowed us to read whole paragraphs at once, greatly improving our comprehension of the genome.”

Social and long-lived giraffes

A five-year study on female giraffes in Tanzania has found that those with lots of friends have higher survival rates than more isolated individuals.

“Grouping with more females, called gregariousness, is correlated with better survival of female giraffes, even as group membership is frequently changing,” says study leader Monica Bond.

There could be a few different reasons for this longevity – including sharing food locations, protection from predators, caring for young and reduced harassment from male giraffes.

The researchers mapped the social behaviours of the giraffes using network analysis algorithms, similar to those used by social media platforms. They found the giraffes’ social benefits were similar to those of humans and other primates. “It seems to be beneficial for female giraffes to connect with a greater number of others and develop a sense of larger community, but without a strong sense of exclusive subgroup affiliation,” says Bond.

Giraffes that lived closer to towns, however, had lower survival rates. This could be because of poaching, which is the leading cause of death in adult female giraffes.