Quirks and Quarks

Feb 11: Trouble for the 'love hormone,' shading Earth with moon dust, making memories with an app and more…

Orca sons inhibit mom’s future offspring and more detail on how the first people got to the Americas

Orca sons inhibit mom’s future offspring and more detail on how the first people got to the Americas

Two prairie voles huddle next to each other.
Prairie voles form monogamous, long-term pairs, where both rodents raise their young pups. These strong bonds are the reason why much of the science of social bonds comes from prairie vole studies. (Nastacia Goodwin)

On this week's episode of Quirks & Quarks with Bob McDonald:

The science behind the 'love hormone' may have a big problem

For decades, scientists have investigated oxytocin's effects on creating bonds between mates and with their offspring by studying monogamous prairie voles. But a new study published in Neuron suggests that genetically "shutting the door" to oxytocin in the rodents has little effect on their bonding or parenting behaviour. Stanford University researcher Nirao Shah says the results highlight the need for a more nuanced understanding of the complex recipe of social bonding behaviors in both prairie voles and humans.

Could moon dust solve our global warming problem?

Physicist and astronomer Benjamin Bromley from the University of Utah has suggested that millions of tons of dust from the Moon could be launched into an orbit between the Earth and Sun to mitigate the impact of global warming. In what could be called "astro-engineering," lunar dust particles would create a cloud to help shade the Earth from a fraction of sunlight that warms the planet. His research was published in PLOS Climate.

Stream of black particles cross the yellow face of the Sun
Simulated stream of dust launched between Earth and the Sun. This dust cloud is shown as it crosses the disk of the Sun, viewed from Earth. Streams like this one can act as a temporary sun shade (Submitted by Benjamin Bromley)

Canadian researchers develop a smartphone app for making memories

Neuroscientists at the University of Toronto, led by Morgan Barense, have created a memory training app called Hippocamera modelled on the way the brain's hippocampus inscribes memory. The hippocampus is thought to reinforce memories by playing back recent events in "fast-forward," teaching other parts of the brain to make connections with an episode we've experienced. The smartphone app uses its camera and an audio cue to create a similar experience, and tests have shown it works reliably for people with and without memory deficits. The research was published in PNAS.

A woman and a man look at a computer display with cross sectional images of a brain.
Neuroscientists Morgan Barense and Bryan Hong examine a fMRI scan. They are part of a team that has developed a memory reinforcement app called Hippocamera. (Diana Tyszko)

Orca sons are costing their mom's a chance at more offspring

The mother-son bond in killer whales is an extraordinarily tight one. Killer whale mothers lavish attention on their sons and even share half her food with them well into adulthood. In return, he can give her lots of grandchildren. Now, according to a new study of the southern resident killer whales off the Pacific coast, this act of devotion may come at the expense of future offspring for the mother. Not a big deal when there were plenty of Chinook salmon to go around — but Michael Weiss, from the University of Exeter and the Center of Whale Research in Washington State, said now that Chinook salmon stocks are depleted, this evolutionary hack might not be so advantageous after all. The study was published in the journal Current Biology.

A mother killer whale breaches the water surface with one of her offspring by her side
Killer whale mothers sacrifice their chance of having more offspring so they can look after their sons well into adulthood. (Kenneth Balcomb/Center For Whale Research)

Crossing the land bridge — and back again. The travels of North America's first settlers

The story of how humans first moved into North America is now clearer — and more complicated — thanks to a few recent studies. A geological analysis of ocean nitrogen isotopes and ice sheet data suggests the Bering land bridge between Siberia and Alaska opened up later and for a shorter period than we previously thought. Jesse Farmer, who did this research at Princeton University, suggests sea levels dropped enough that the land bridge surfaced about 35,700 years ago. Because of the difficulty of passing the vast ice sheets, many authorities now think people took a coastal route down into North America. Summer Praetorious, a research geologist from the U.S.G.S. ran climate models with paleo-ocean data to identify two periods when coastal movement would have been most practical. Though the land bridge was submerged again at the end of the ice age, that didn't stop people from crossing between the continents — but not always in the direction you may think. Cosimo Posth from the University Tübingen said their study of ancient genomes in East Asia suggests there was also a backflow of migrants moving North America back into East Asia.

Map of area between Siberia and Alaska showing current land in brown and exposed land at low sea level in yellow
During the Last Glacial Maximum, the low sea levels exposed a vast land area that extended between Siberia and Alaska known as Beringia, which included the Bering Land Bridge (National Park Service)