Meat and three veg is the perfect meal for an extinct giant ground sloth – Mylodon darwinii – that lived 10,000 years ago.
Researchers from the American Museum of Natural History analysed amino acids – the building blocks of proteins – found in preserved sloth hair and learnt that the sloths were probably omnivores that chowed down on both meat and plants.
Modern sloths are herbivores – fully vegetarian – and their amino acid profile lacked some of the amino acids found in the ground sloth. Instead, the ground sloths’ profile was more similar to present-day omnivores.
“These results, providing the first direct evidence of omnivory in an ancient sloth species, demands re-evaluation of the entire ecological structure of ancient mammalian communities in South America, as sloths represented a major component of these ecosystems across the past 34 million years,” says Julia Tejada, who led the study, published in Scientific Reports.
Words with dogs
Some dogs are so smart that they can learn their toy’s names – a skill comparable to the language capabilities of a one-year-old human.
In a study, published in The Royal Society, researchers tested six ‘Gifted Word Learner’ collies and found that they could memorise the names of 12 new toys with ease. Four even retained this information two months later.
The researchers suggest Gifted Word Learners could be a useful model for studying the mental mechanisms of word acquisition.
The Earth’s core
The Earth might have a hard exterior, but it might be both mushy and hard on the inside.
New research, published in Physics of The Earth and Planetary Interiors, suggests that the Earth has a mix of liquid and soft and hard structures that vary across the top of the inner core.
The core is so deep that the researchers had to use the only type of data they could collect – earthquake waves.
“Illuminated by earthquakes in the crust and upper mantle, and observed by seismic observatories at Earth’s surface, seismology offers the only direct way to investigate the inner core and its processes,” says lead author Rhett Butler, of the University of Hawai‘i.
The seismic waves vary in speed depending on the types of minerals, density and temperature of the medium they travel though, so the researchers assessed these data and found there was quite a bit of variation.
“In stark contrast to the homogeneous, soft iron alloys considered in all Earth models of the inner core since the 1970s, our models suggest there are adjacent regions of hard, soft, and liquid or mushy iron alloys in the top 150 miles [241 kilometres] of the inner core,” says Butler. “This puts new constraints upon the composition, thermal history, and evolution of Earth.
“Knowledge of this boundary condition from seismology may enable better, predictive models of the geomagnetic field which shields and protects life on our planet.”
Seeing cancer cells
Visualising cancer cells could be as simple as using the right microscope slide.
An innovative invention called the NanoMslide, developed at LaTrobe University, can detect cancer cells in patients. It has a special nanoscale surface that causes cells to change colour if they are diseased.
“Current approaches to tissue imaging often rely on staining or labelling cells in order to render them visible under the microscope,” says Brian Abbey, who led the project.
“Even with staining or labelling, it can be challenging for pathologists to detect cancer cells, with the risk that some samples are misdiagnosed, particularly during the very early stages of disease.
“Recent breakthroughs in nanotechnology have allowed us to manipulate the interaction of light with biological tissue so that abnormal cells appear to have a different colour to healthy ones. Comparing images from our slides to conventional staining is like watching colour television when all you’ve seen before is black and white.”
The study was published in Nature.
Perseverance finds a lake system
The Mars rover Perseverance has sent rock pics back to Earth that suggest there was an ancient river that may have helped form the Jezero Crater.
“It’s hugely useful for the mission and guiding us to select samples for return to Earth,” says astrobiologist Amy Williams, from the University of Florida. “We’re applying all of our usual tool sets as geologists to understand what these layers mean. It’s amazing to me that you can do that on another world.”
The images reveal a transition from a river flowing into a lake to episodic torrents of floodwater that deposited the boulders.
“It helps us understand so much more about the water cycle on Mars,” Williams says. “From orbital images, we knew it had to be water that formed the delta, but having these images is like reading a book instead of just looking at the cover.”
“This is the closest I will ever get to going to Mars and doing this work in person. Seeing these rocks as I would in real life, looking up at them, is really staggering and really beautiful.”
Deborah Devis is a science journalist at Cosmos. She has a Bachelor of Liberal Arts and Science (Honours) in biology and philosophy from the University of Sydney, and a PhD in plant molecular genetics from the University of Adelaide.
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