Science

Shark bites and fatalities ticked up worldwide last year, with Australia accounting for a disproportionate number of deaths resulting from heightened contact with humans even as the ancient predators face a wider extinction crisis

There were 69 unprovoked attacks in 2023, up slightly from 63 in 2022, and ten deaths, which is double the year before and a 12-year-high, according to the International Shark Attack File, an annual global report published Monday by the University of Florida.

In places where we need to protect valuable plants – whether for ecological or economic reasons – local herbivores can cause significant damage.

Current solutions often involve killing the problem animals. But this is increasingly unacceptable due to animal welfare concerns and social pressures. Physical barriers such as fences can be expensive, and aren’t always practical. We need other options.

Recently, our team discovered that herbivores – plant-eating mammals – primarily use their sense of smell to tell which plants they want to eat or avoid.

In our study published today in Nature Ecology & Evolution, we show how we can use this reliance on smell to nudge wallabies away from vulnerable native tree seedlings. We artificially created and deployed the key smells of a shrub wallabies avoid.

Herbivore-induced headaches

Hungry plant eaters are a concern for conservationists, farmers and foresters alike. They can devastate revegetation efforts and post-fire recovery, destroying more than half the seedlings in these areas.

Every year, they cause billions of dollars of damage in forestry and agriculture. Herbivores also pose a risk to the long-term survival of many threatened plant species.

The most effective control strategies will likely work with a herbivore’s natural motivations – understanding and harnessing what drives the animal to find or avoid certain plants.

Previously, research had primarily focused on what herbivores were eating, but had never really asked how they find the food in the first place.

Our approach puts a new twist on “olfactory (smell) misinformation” or “chemical camouflage” approaches. In recent studies, these methods have substantially reduced invasive predators eating threatened bird eggs in New Zealand, and house mice eating agricultural wheat grain in Australia.

A swamp wallaby munching on some grass. Like other plant-eating mammals, they use their sense of smell to find delicious plants.Joshua Prieto/Shutterstock

A landscape of smells

In navigating a scent landscape, herbivores use odour to recognise and select among plants and plant patches. Odour is key in guiding the foraging of marsupials in Australia, elephants in Africa and Asia, and deer in the United States.

With this in mind, we explored whether the smell of a plant they don’t like could be enough to nudge animals away from highly palatable native tree seedlings.

Mammalian herbivores use their noses to navigate complex smell landscapes where odor is emitted from food, predators, competitors and potential mates. Finnerty et al., BioScience, 2022

To test this idea, we focused on swamp wallabies foraging in a eucalypt woodland in eastern Australia. Studies have shown having too many swamp wallabies around can limit the number of eucalypt seedlings that survive to become trees. Swamp wallabies also have a fantastic sense of smell – they can find just a few eucalypt leaves buried underground among complex vegetation.

Using an approach we recently developed, we found the key scent compounds of a plant we know wallabies avoid – the native shrub Boronia pinnata.

We then mixed these compounds together to create “informative virtual neighbors”. They were “informative” as our mix of compounds mimicked what a wallaby would recognise as Boronia pinnata, “virtual” as we were not actually deploying the real shrub, and “neighbors” as we placed these smells in the bush next to eucalypt seedlings we were trying to protect.

In our study, a virtual neighbor was a small glass vial with a few millilitres of the mixture, with a tube pierced through the lid so the smell could waft out.

Using odors instead of real plants is a type of olfactory misinformation – it sends a deceptive message to the animals.

We deployed the virtual neighbor vials in custom-built contraptions that secured vials to the ground and provided protection from the weather. Finnerty et al., Nature Ecology & Evolution, 2024

Real and virtual neighbours

We also compared if virtual neighbors were as good as the real thing in protecting eucalypt seedlings from being eaten by wallabies.

Five virtual neighbor vials or real Boronia pinnata plants were spaced evenly around single eucalypt seedlings the wallabies would find highly palatable. (We also had two types of controls: a seedling with nothing around it, and a seedling surrounded by five empty vials.)

Using remote cameras for 40 days, we recorded how long it took wallabies to find and munch on the eucalypt seedlings.

The results were staggering. Seedlings were 20 times less likely to be eaten when surrounded by virtual neighbours than for both controls. This was equivalent to using real B. pinnata plants, but better because vials don’t compete with seedlings for water and other resources.

A single eucalypt seedling surrounded by five virtual neighbors (a) and five real plant neighbors (b). Finnerty et al., Nature Ecology & Evolution, 2024

A highly effective approach

The success of our study indicates we could use this approach as a new management tool – one that works by influencing the animals’ behavior rather than trying to get rid of them.

We believe the concept behind developing virtual neighbors is directly transferable to any herbivore, mammal or otherwise, that uses plant odour to forage.

All herbivores avoid some plant species. With future development, we can deploy smelly virtual neighbors as a non-deadly and cost-effective tool to reduce the problems caused by overzealous herbivores.

Planets orbit their parent stars while separated by enormous distances – in our solar system, planets are like grains of sand in a region the size of a football field. The time that planets take to orbit their suns have no specific relationship to each other.

But sometimes, their orbits display striking patterns. For example, astronomers studying six planets orbiting a star 100 light years away have just found that they orbit their star with an almost rhythmic beat, in perfect synchrony. Each pair of planets completes their orbits in times that are the ratios of whole numbers, allowing the planets to align and exert a gravitational push and pull on the other during their orbit.

This type of gravitational alignment is called orbital resonance, and it’s like a harmony between distant planets.

I’m an astronomer who studies and writes about cosmology. Researchers have discovered over 5,600 exoplanets in the past 30 years, and their extraordinary diversity continues to surprise astronomers.

Harmony of the spheres

Greek mathematician Pythagoras discovered the principles of musical harmony 2,500 years ago by analyzing the sounds of blacksmiths’ hammers and plucked strings.

He believed mathematics was at the heart of the natural world and proposed that the Sun, Moon and planets each emit unique hums based on their orbital properties. He thought this “music of the spheres” would be imperceptible to the human ear.

Four hundred years ago, Johannes Kepler picked up this idea. He proposed that musical intervals and harmonies described the motions of the six known planets at the time.

To Kepler, the solar system had two basses, Jupiter and Saturn; a tenor, Mars; two altos, Venus and Earth; and a soprano, Mercury. These roles reflected how long it took each planet to orbit the Sun, lower speeds for the outer planets and higher speeds for the inner planets.

He called the book he wrote on these mathematical relationships “The Harmony of the World.” While these ideas have some similarities to the concept of orbital resonance, planets don’t actually make sounds, since sound can’t travel through the vacuum of space.

Orbital resonance

Resonance happens when planets or moons have orbital periods that are ratios of whole numbers. The orbital period is the time taken for a planet to make one complete circuit of the star. So, for example, two planets orbiting a star would be in a 2:1 resonance when one planet takes twice as long as the other to orbit the star. Resonance is seen in only 5% of planetary systems.

Orbital resonance, as seen with Jupiter’s moons, happens when planetary bodies’ orbits line up – for example, Io orbits Jupiter four times in the time it takes Europa to orbit twice and Ganymede to orbit once. WolfmanSF/Wikimedia Commons

In the solar system, Neptune and Pluto are in a 3:2 resonance. There’s also a triple resonance, 4:2:1, among Jupiter’s three moons: Ganymede, Europa and Io. In the time it takes Ganymede to orbit Jupiter, Europa orbits twice and Io orbits four times. Resonances occur naturally, when planets happen to have orbital periods that are the ratio of whole numbers.

Musical intervals describe the relationship between two musical notes. In the musical analogy, important musical intervals based on ratios of frequencies are the fourth, 4:3, the fifth, 3:2, and the octave, 2:1. Anyone who plays the guitar or the piano might recognize these intervals.

Musical intervals can be used to create scales and harmony.

Orbital resonances can change how gravity influences two bodies, causing them to speed up, slow down, stabilize on their orbital path and sometimes have their orbits disrupted.

Think of pushing a child on a swing. A planet and a swing both have a natural frequency. Give the child a push that matches the swing motion and they’ll get a boost. They’ll also get a boost if you push them every other time they’re in that position, or every third time. But push them at random times, sometimes with the motion of the swing and sometimes against, and they get no boost.

Orbital resonance can cause planets or asteroids to speed up or start to wobble.

For planets, the boost can keep them continuing on their orbital paths, but it’s much more likely to disrupt their orbits.

Exoplanet resonance

Exoplanets, or planets outside the solar system, show striking examples of resonance, not just between two objects but also between resonant “chains” involving three or more objects.

Virtual reality (VR) headsets are increasingly popular among adults and children. They are part of extended reality environments, which “enable ever more realistic and immersive experiences”.

VR provides entry into computer-generated 3D worlds and games with different environments and interactions. Sometimes this is loosely referred to as the “metaverse”.

The majority of VR headsets have a lower age limit of 10–13 years due to safety concerns of extended reality technologies in general and VR headsets in particular.

But VR is increasingly used by young children, even of preschool age. These immersive technologies make it difficult to monitor children’s physical and emotional experiences and with whom they interact. So what are the dangers, and what can we do to keep the kids safe?

The good and the bad

VR allows children to dive into a digital world where they can immerse themselves into different characters (avatars). Thanks to the richness of the stimuli, VR can give the illusion of actually being in the virtual location – this is called “virtual presence”.

If children then interact with other people in the virtual world, the psychological realism is enhanced. These experiences can be fun and rewarding.

However, they can also have negative impacts. Children tend to have difficulty distinguishing between what occurs within VR and in the real world.

As children identify with their avatars, the boundary between them and the VR device is blurred when playing in the metaverse.

Children can even develop traumatic memories when playing in virtual worlds. Due to the immersive nature of VR, the sense of presence makes it feel as if the child’s avatar is actually “real”.

Research is still emerging, but it is known children can form memories from virtual experiences, which means sexual abuse that occurs virtually could turn into a real-world traumatic memory.

The rise of ‘cyber grooming’

Research has found that online predators use different grooming strategies to manipulate children into sexual interactions. This sometimes leads to offline encounters without the knowledge of parents.

Non-threatening grooming strategies that build relationships are common. Perpetrators may use friendship strategies to develop a relationship with children and to build trust. The child then views the person as a trusted friend rather than a stranger. As a result, the prevention messages about strangers learned through education programs are ineffective in protecting children.

A recent meta-analysis found that online sex offenders are usually acquaintances. Unsurprisingly, a proportion of adult predators pretend to be peers (that is, other children or teens).

Sexual approaches by adults occur more commonly on platforms that are widely used by children. “Sexual communication with a child” offences, according to police statistics from the United Kingdom, increased by 84% between 2017–18 and 2021–22.

Due to the hidden nature of cyber grooming, it is difficult to know the true prevalence of this issue. Some police reports in Europe indicate that approximately 20% of children have experienced online sexual solicitation, and up to 25% of children reported sexual interaction with an adult online.

Concerning reports by Europol indicate that children have been drawn into erotic role play online. In interviews with researchers, some parents have also shared anecdotal experiences of their children being exposed to explicit sex acts on social online gaming platforms such as Roblox.

Such encounters have the potential to create memories as if the virtual experience had happened in real life.

For parents it is important to know that cyber groomers are well versed in the use of extremely popular virtual worlds. These provide predators with anonymity and easy access to children, where they can lure them into sexual engagement.

Children can immerse themselves into virtual words, where interacting with others is fun, but potentially confusing. Frame Stock Footage/Shutterstock

Parents must try VR themselves

A recent report from the Internet Watch Foundation charity reports that a record number of young children have been manipulated into performing sexual acts online.

Through the metaverse, a sexual offender can be virtually brought into a child’s bedroom and engage in sexual behaviours through the child’s VR device. As VR worlds become more immersive, the danger for children only increases.

Grooming occurs where parents least expect it to happen. To mitigate this danger, parents need to be aware of online grooming patterns – such as isolating the child, developing their trust and asking them to hide a relationship.

Recognising the signs early can prevent the abuse from happening. But this can be difficult if parents aren’t familiar with the technology their child is using.

To help them understand what their children experience in extended reality environments, parents must familiarise themselves with VR and the metaverse.

If parents experience and experiment with the VR technology themselves, they can have conversations with their children about their experiences and understand with whom the child might interact with.

This will allow parents to make informed decisions and put tailored safeguarding measures in place. These safeguards include reviewing the parental controls and safety features on each platform, and actively learning what their children are playing and whom they are interacting with.

With such safeguards in place, parents can allow their children to have fun with VR headsets while keeping them protected.

Earlier this week, Elon Musk announced his brain-computer interface company, Neuralink, had implanted a device in a human for the first time. The company’s PRIME study, approved by the US Food and Drug Administration last year, is testing a brain implant for “people with paralysis to control external devices with their thoughts”.

In the past few years, Neuralink has faced investigation for mistreatment of lab animals and seen the departure of several company executives. Nevertheless, the PRIME trial is a significant milestone for a company less than ten years old.

Vertebrates are defined as all animals that possess a vertebral column, or backbone. Most living vertebrates also possess jaws, teeth and paired fins or limbs.

Fossils of the earliest vertebrates help us understand not only how these features originated, but also how they evolved and diversified over time.

Small dogs with long noses, such as whippets and miniature dachshunds, live for years longer than large flat-faced breeds such as English bulldogs, new research said on Thursday.

The study, which is based on data from more than half a million dogs across the UK, aims to help people planning to get a dog ensure they choose a breed that will have a long and healthy life.