Quirks & Quarks

Mar 18: Earliest horsepeople, whales use 'vocal fry', plankton might migrate poleward and more...

Mapping a fruit fly brain and understanding the cuddly, cute and really strange koala

Mapping a fruit fly brain and understanding the cuddly, cute and really strange koala

two koalas sleeping in a tree
A new book looks at the curious biology and uncertain future of Australia's iconic koala. (Eeqmcc from Getty Images/Canva)

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

Markings on the leg and butt bones of early riders indicate people started riding horses 5,000 years ago

Scientists have found telltale signs of horse riding on skeletons from thousands of years ago in southeast Europe. This new study, published in the journal Science Advances was done by a team including David Anthony, an anthropologist from Harvard University and Hartwick College. The evidence included marks on the bone of powerful muscles used to stay astride a horse, and tailbone injuries. The researchers say this casts light on when people started riding horses as they domesticated them.

The full human skeleton is seen still in the ground where it was discovered.
Grave of a Yamnaya horse rider discovered in Strejnicu, Romania. The man, 30 to 40 years old at the time of death, displays skeletal traits typical of "horsemanship syndrome." (Alin Frînculeasa)

Whales use 'vocal fry' to echolocate at depth

Many species of toothed whale – a group that included dolphins and porpoises – are able to hunt at extreme depths in the dark by using echolocation. But in very deep water their lung function is limited so they can't use air from the lungs to produce echolocation clicks. Coen Elemens, a professor of bioacoustics at the University of Southern Denmark found that by moving air from lungs to the nasal cavity, the whales are able to echolocate, but the sound they make is different from their usual social calls. It is, in fact, analogous to vocal fry in humans. His study was published in Science.

Xray like scan of the head of a porpoise showing where sound is made in the nasal cavity using different colours
Scan of the sound producing nose of a porpoise showing parts of the two sound sources, and the fatty melon that conducts sound into the water (Christian B. Christensen, Aarhus University)

Fossils suggest that if equatorial oceans get too warm, plankton may desert

A new study of fossil remains of plankton suggests that these ecosystem-building organisms may abandon equatorial waters if the planet continues to warm. Researchers Adam Woodhouse and Anshuman Swain analyzed a huge database of foraminifera fossils – small, hard shelled plankton – to find out where and when the plankton lived, how deep its habitat was, and the conditions of the ocean around it. Their results, published in Nature, suggest that the tropical plankton living around the equator now moved there from Earth's polar regions at the start of the cooling period 8 million years ago. Woodhouse said the concern is that if the present-day equatorial waters get too warm, the plankton may move poleward, leaving those waters impoverished of life.

A microscopic image of a single-celled organism
A microscope image of a shelled plankton. According to research from The University of Texas at Austin, plankton populations like this flourished in the tropics during past global cooling and may vanish as the climate warms. (Tracy Aze)

Scientists have mapped the most complex animal brain yet - and it's the size of a grain of salt

Researchers have released a map of all of the thousands of neurons and half-million neural connections of a larval fruit fly. Joshua Vogelstein a biomedical engineer at Johns Hopkins University Scientists is hopeful that this may be a step to understanding the complexities of the human brain, including thought. The research was published in Science.

An abstract image of a fruit fly brain shows neurons as coloured balls and the connections bwtween them as coloured strands
A representation of the map of a larval fruit fly brain. The full map shows over 3 thousand neurons and the over one-half a million connections between them. (Johns Hopkins University / University of Cambridge)

A new book explores the unique biology and uncertain fate of Australia's iconic koala

Australia's devastating wildfire season in 2019-2020 had massive impacts on wildlife, and in particular on koalas who were already threatened and in decline in much of their historical range. Bob McDonald speaks to biologist and science writer Danielle Clode about this unique marsupial and her new book Koala: A Natural History and An Uncertain Future.

Koala on left with a mouthful of green leaves, author Danielle Clode on the right
A koala snacks on eucalypt leaves while posing with author Danielle Clode (Submitted by Danielle Clode)