The concept of zero—less than one, nothing, nada—is deceptively complex. The first placeholder zero dates back to around 300 BCE, and the notion didn’t make its way to Western Europe until the 12th century. It takes children until preschool to wrap their brains around the concept. But scientists in Australia recently discovered a new animal capable of understanding zero: the honey bee. According to Vox, a new study finds that the insects can be taught the concept of nothing.
A few other animals can understand zero, according to current research. Dolphins, parrots, and monkeys can all understand the difference between something and nothing, but honey bees are the first insects proven to be able to do it.
The new study, published in the journal Science, finds that honey bees can rank quantities based on “greater than” and “less than,” and can understand that nothing is less than one.
The researchers trained bees to identify images in the lab that showed the fewest number of elements (in this case, dots). If they chose the image with the fewest circles from a set, they received sweetened water, whereas if they chose another image, they received bitter quinine.
Once the insects got that concept down, the researchers introduced another challenge: The bees had to choose between a blank image and one with dots on it. More than 60 percent of the time, the insects were successfully able to extrapolate that if they needed to choose the fewest dots between an image with a few dots and an image with no dots at all, no dots was the correct answer. They could grasp the concept that nothing can still be a numerical quantity.
It’s not entirely surprising that bees are capable of such feats of intelligence. We already know that they can count, teach each other skills, communicate via the “waggle dance,” and think abstractly. This is just more evidence that bees are strikingly intelligent creatures, despite the fact that their insect brains look nothing like our own.
Considering how far apart bees and primates are on the evolutionary tree, and how different their brains are from ours—they have fewer than 1 million neurons, while we have about 86 billion—this finding raises a lot of new questions about the neural basis of understanding numbers, and will no doubt lead to further research on how the brain processes concepts like zero.
All birds are living dinosaurs, but the dagger-clawed cassowary especially looks the part. Even wildlife biologists call cassowaries the world's most dangerous bird—and yes, it has been known to kill people. Here’s everything you need to know about the majestic and terrifying beast.
1. The southern cassowary is Earth's second-heaviest bird.
Scientists recognize three living species of cassowary—all of which live in New Guinea, northeastern Australia, and nearby islands. The dwarf cassowary is the smallest, with an average height of around 3 feet. The northern cassowary, an orange-throated behemoth, can stand nearly 5 feet tall. The southern cassowary is bigger than both at 5 foot 6 inches tall. The only two birds that grow taller are ostriches and emus. Adult southern cassowary females can weigh up to 157 pounds, and males 121 pounds, making them the second-heaviest birds on the planet behind ostriches.
2. Cassowaries have dangerous feet.
In the southern cassowary's Australian range, you might come across warning signs that read “Be Cass-o-wary.” Heed this advice. Normally, cassowaries are shy and reclusive, but they can become aggressive when threatened and strike back with powerful head-butts and pecks. Their most dangerous weapon is the razor-sharp claw on the middle toe of each foot, which, in southern cassowaries, grows to be 5 inches long. The birds deliver a series of downward kicks that have been known to break bones and cause fatal lacerations.
3. Rearing cassowary chicks is the father's job.
Female cassowaries breed with several partners. After laying her eggs, she abandons them, at which point the males take over and incubates the eggs for at least 50 days. The fathers never leave the nest, not even to eat or drink. Once the eggs hatch, males spend the next nine months raising and defending the chicks. Males also teach the chicks how to forage so they can fend for themselves.
4. Cassowaries are surprisingly good jumpers.
What’s scarier than a 150-pound modern dinosaur with killer claws? One that can leap 7 feet off the ground. To get the most out of those toe daggers, cassowaries will sometimes jump feet-first at an attacker, with the claws slashing downward in midair. They’re also great swimmers and sprinters with a top running speed of 30 miles per hour.
5. Cassowaries have a spike hidden on each wing.
Cassowaries are closely related to emus and more distantly related to ostriches, rheas, and kiwis. All of these birds, known as ratites, are flightless. Cassowaries have small vestigial wings tipped with a small claw that probably serves no purpose.
6. Cassowaries are frugivores that also eat their own poop.
Wild cassowaries dine mainly on fruits and berries that fall to the ground in the rainforests they call home. A typical southern cassowary can eat up to 11 pounds of fruit a day, along with plenty of fungi and the occasional dead animal for some extra protein.
Cassowaries also hunt rodents, snails, and lizards. Poop is yet another item on the menu. Cassowary poop usually contains half-digested fruit, which still has plenty of nutritional value, so the birds devour each other’s droppings as well as their own.
7. The function of their odd crests, or casques, is a mystery.
Cassowaries sport royal-blue necks and shaggy black feathers, but their most distinctive feature is the helmet-like casque that sits above the eyes. The bony protrusion is covered with a sheath of keratin (the material that makes up your fingernails), and it begins to develop when the bird is around 2 years old. Scientists have long speculated, sometimes wildly, about its purpose. One theory is that casques help cassowaries push aside forest underbrush. The casques might also be used to attract the opposite sex.
A more interesting hypothesis involves how these birds communicate. Cassowaries emit very deep bellows—the lowest bird calls known to humans. Perhaps their casques amplify and broadcast these sounds by acting as a resonance chamber. Certain crested dinosaurs (like Parasaurolophus of Jurassic Park fame) may have produced calls the same way.
8. Cassowaries can live for decades (at least in zoos).
Naturalists don’t know how long a wild cassowary can expect to live. A few southern cassowaries have reached their 40th birthdays in captivity. In zoos, northern cassowaries can top that figure—one reached the age of 48 and another may have been as old as 61. The average lifespan for captive dwarf cassowaries is about 26 years.
9. Cassowaries have strange genitalia.
Both sexes have a pseudo-penis that isn’t connected to any of their internal reproductive organs. When cassowaries mate, the male ejaculates through his cloaca, an orifice at the base of the pseudo-penis. When they aren’t mating, males' pseudo-penis is turned inside out and retracted.
Such peculiar anatomy has given the cassowary a unique place in New Guinean culture and folklore. For example, the native Mianmin people tell stories about a human woman with a penis who somehow transformed into a cassowary. Another indigenous group, the Umeda, put on a regular ceremony called “ida.” A big event that lasts for two days and nights, the ritual involves a fertility dance which calls for two male dancers who represent a pair of cassowaries. Each player is given a heavy mask and is coated with charcoal from head to toe.
10. At least two unfortunate humans have been killed by cassowaries.
To date, there have been only two verified reports of a cassowary taking human life. In April 1926, a cassowary fatally charged 16-year-old farmer Phillip McLean in north Queensland, Australia. More recently, a 75-year-old Florida man was killed by a cassowary he had kept as a pet at his exotic bird farm.
In 1999, Queensland Parks and Wildlife ranger Christopher P. Kofron analyzed 150 documented cassowary-on-human attacks. Twenty-two percent of attacks resulted from the bird defending itself, its eggs, or its chicks, 5 percent were triggered by somebody getting too close to the cassowary’s food, and 73 percent involved a cassowary that associated people with free meals. Many cassowaries in Australia had lost their natural shyness around humans thanks to people feeding them bananas and watermelon. Today, feeding a wild one is against the law, but the practice continues.
Following the fire that tore through Notre-Dame in Paris on April 15, fire officials shared that the church's bell towers, stone facade, and many of its precious artifacts had escaped destruction. But the building's centuries-old features weren't the only things threatened by the blaze: The three beehives on the roof of the cathedral were also at risk. Now, CNN reports that the bees of Notre-Dame and their homes have survived the historic fire.
Notre-Dame's beehives are a relatively recent addition to the site: They were placed on the first-floor rooftop over the sacristy and beneath one of the rose windows in 2013. Nicolas Geant, the church's beekeeper, has been in charge of caring for the roughly 180,000 Buckfast bees that make honey used to feed the hungry.
Most people weren't thinking of bees as they watched Notre-Dame burn, but when the fire was put out, Geant immediately searched drone photographs for the hives. While the cathedral's wooden roof and spire were gone, the beehives remained, though there was no way of knowing if the bees had survived without having someone check in person. Geant has since talked to Notre-Dame's spokesperson and learned that bees are flying in and out of the hives, which means that at least some of them are alive.
Because the beehives were kept in a section 100 feet below the main roof where the fire was blazing, they didn't meet the same fate as the church's other wooden structures. The hives were likely polluted with smoke, but this wouldn't have hurt the insects: Bees don't have lungs, so smoke calms them rather than suffocates them.
Notre-Dame's bees may have survived to buzz another day, but some parts of the building weren't so lucky. France has vowed to rebuild it, with over $1 billion donated toward the cause so far.