A passion for the natural world drives many of our adventures. And when we’re not actually outside, we love delving into the discoveries about the places where we live and travel. Here are some of the best natural history links we’ve found this week.
Saturn’s rings are disappearing: Rock and ice form a halo of concentric circles around Saturn, its famous rings, but these rings are starting to disappear. Every year, micrometeorites and radiation electrify particles within the rings. These then start spiraling toward the planet, ultimately vaporizing in Saturn’s atmosphere.
“[We are] looking at Saturn’s rings in their heyday,” said planetary scientist James O’Donoghue.
Eventually, the rings will vanish completely. The good news is, this will take 300 million years, so there is still time to view the beautiful rings. The big mystery is how the rings came to be in the first place. Evidence suggests that the rings are between 10 and 100 million years old, but the debate about their formation rages on.
Woodland Caribou. Photo: Shutterstock
Caribou care
Indigenous people bringing caribou back from brink of extinction: Woodland caribou form relatively small herds in old-growth forests and on mountain slopes. In Canada, these herds have dwindled dramatically. Moose and deer moved into caribou territory after logging and oil and gas extraction altered the habitat. This, in turn, attracted wolves. One-third of the herds in southwestern Canada have been functionally extinct since 2000.
The West Moberly and Saulteau First Nations teamed up to try and save a fading herd, the Klinse-Za, after a neighboring herd had disappeared completely. The people catch and transport pregnant caribou to a specially built pen, where they care for the animals.
Later, they release the females and new calves with GPS tracking collars. Paid hunters keep the growing wolf population at bay. Before this intervention began in 2014, the Klinse-Za herd was declining by 10% each year. Since then, the population has grown by 12% a year.
Rivers contribute to Amazon’s bird diversity: How did life in the Amazon become so diverse? One research group decided to focus this question on birds. They discovered that the region’s ever-changing small river systems spur the evolution of new bird species. Though birds can fly, rivers in the southern Amazon rainforest still isolate species. This eventually causes genomic divergence. How quickly the rivers change course determines this speciation. If they move slowly, speciation takes place. Fast changes of course allow the birds to separate, then recombine before speciation can occur.
The Perseverance Rover. Photo: NASA
Two speeds of sound on Mars
Sound recorded on Mars: NASA’s Perseverance Rover has recorded sound on Mars for the first time. On February 19, they took the first recording of the planet’s acoustic environment. They have been analyzing it ever since.
Sound on Mars falls within the audible spectrum for humans, between 20Hz and 20kHz. Though sound exists, it turns out that Mars is a very quiet place. Apart from wind, sound is rare.
Scientists were surprised to discover that there are two speeds of sound on Mars, one for high-pitched sounds and one for low frequencies.
One of the earliest meat-eating mammals was saber-toothed: Scientists discovered a new species of extinct mammal. Diegoaelurus vanvalkenburghae was a bobcat-sized animal that stalked the rainforests of modern San Diego 42 million years ago. It was one of the first mammals to have saber-like fangs.
“Those big fangs were either used to bite into the throat of prey or to rip and tear flesh,” said paleontologist Ashley Poust.
The species was a hypercarnivore, meaning a creature that ate almost exclusively meat. Such animals, such as polar bears and the big cats, exist today but they were quite rare in the Eocene.
Cycads face extinction. Photo: Shutterstock
Ancient plants threatened
Plants older than dinosaurs face extinction: Cycads are older than the earliest dinosaurs. They began growing around 280 million years ago. Since then, they have survived multiple mass extinctions and changed radically to become the plants we know today.
Despite their resilience, they are now endangered. Habitat loss combined with a growing trade in the plants threatens their existence.
“Cycads are the most threatened group of organisms assessed to date,” said botanist Cristina Lopez-Gallego. Currently, 62% of the 300 living cycad species are on the IUCN Red List.
