You might have missed: exotic cats recognise familiar voices; volcanic ancient Mars; ants and Earth’s magnetic field

Exotic cats can recognise familiar humans’ voices

A new study has found that non-domesticated Felidae species – including lions, tigers, and cheetahs – have the remarkable ability to tell the difference between familiar and unfamiliar human voices.

US researchers studied 25 exotic cats while exposing them to audio playbacks of familiar and unfamiliar humans. They found the cats responded more quickly, intensely, and for longer durations, to familiar voices compared to unfamiliar ones, regardless of the use of their names or rearing history.

The findings, published in PeerJ, suggest that human contact, rather than domestication, is associated with this ability to discriminate between human voices.

“Non-group-living animals can exhibit social cognitive abilities such as heterospecific (different species) vocal recognition so we should not neglect the study of social cognition in less highly social species,” says co-author Jennifer Vonk, a cognitive psychologist at Oakland University.

Does sugar-free candy and gum give you gas?

Sorbitol is a sugar alcohol used in sugar-free gum, mints, candy and other products. It’s also found naturally in apricots, apples, avocados and other foods. At high levels, it can cause bloating, cramps and diarrhea, but for some people ingesting even a small amount causes problems.

A new study in mice has identified that sorbitol intolerance occurs due to reductions in the number of Clostridia bacteria, which break down sorbitol in the gut.

The researchers found that, after mice were given antibiotics and fed a diet high in saturated fat, cells lining the gut used less oxygen, increasing oxygen levels and decreased Clostridia.

By feeding the mice a gut bacterium, Anaerostipes caccae, that produces butyrate – a short-chain fatty acid that reduces oxygen levels in the large intestine – they were able to restore normal levels of Clostridia and protect the mice from sorbitol-induced diarrhea.

“Our study provides a completely new starting point for approaches to diagnose, prevent and treat sorbitol intolerance,” says senior author Andreas Bäumler, vice chair of research in the University of California Davis Department of Medical Microbiology and Immunology in the US.

The research is published in Cell.

Ancient Mars was more volcanic than we realised

Mars had much more diverse volcanism in its past than previously thought, according to the findings of new study in Nature Astronomy.

“We have known for decades that Mars has volcanoes, but most of the recognised volcanoes correspond to large basaltic shield volcanoes similar to the ones that make up Hawaii,” says first author Joseph Michalski, a geologist at the University of Hong Kong.

Fig01 850
Topographic data are draped over infrared image data showing complex tectonic structures and volcanic deposits in the Eridania region of Mars. Warm colours are higher elevation. Credit: NASA/Mars Odyssey/HRSC

“In this work, we show that the ancient crust has many other types of volcanoes such as lava domes, stratovolcanoes, calderas and large shields of ash, not lava.

“Further, most scientists see Mars as a planet composed of basalt, which has low silica content and represents little crustal evolution, but these volcanoes have high silica content which means they formed from a complex process of magma evolution not known before.”

The paper suggests that intense volcanism caused the ancient Martian crust to collapse into the mantle where the rocks re-melted, resulting in magmas that have high silica. This tectonic process, called vertical tectonics, is hypothesised to have also occurred on Earth more than 3 billion years ago.

These ants navigate using Earth’s magnetic field

Desert ants of the Cataglyphis genus have the peculiar ability to orient themselves to the Earth’s magnetic field and researchers have now discovered the previously unknown regions where this magnetic information is processed.

Photograph of a little ant on sand next to an entrance to its nest
The desert ant Cataglyphis nodus at its nest entrance – an inconspicuous hole in the ground that cannot be seen from the ant’s perspective. To find its way back there, the ant uses the earth’s magnetic field during its learning walks. Credit: Robin Grob

A new paper in the journal PNAS has identified that this processing occurs within the ants’ internal compass – the central complex – and in the animals’ learning and memory centres – the mushroom bodies.

The team now wants to investigate which sensory organ the ant receives this magnetic information through and via which sensory pathways it is transmitted and processed. This has not yet been achieved in any animal species that orients itself to the Earth’s magnetic field.

Sign up to our weekly newsletter

Please login to favourite this article.