Study shows sharks have personalities

May 27, 2016

For the first time a study led by researchers at Macquarie University has observed the presence of individual personality differences in Port Jackson sharks.

A team of researchers from Macquarie's Department of Biological Sciences observed the behaviour of sharks from the east coast of Australia and found that individual sharks had distinct and consistent responses when exposed to an unfamiliar environment and stress.

In humans our personality defines who we are and how we are likely to respond to certain situations. If you know someone well enough, it is possible to predict how they will likely respond in given situations. That is, their behaviour tends to demonstrate repetition over time or in similar situations. It is this behavioural stability and predictability that defines personality.

"Over the past few decades, personality research has shown that nearly 200 species of animals demonstrate individual personality. Personality is no longer considered a strictly human characteristic, rather it is a characteristic deeply engrained in our evolutionary past," says lead author Evan Byrnes.

Trials were designed to test the sharks' boldness, which is a measure of their propensity to take risks, but also an influencer of individual health through its correlation with stress hormones and associated physiological profiles.

The sharks were first introduced to a tank where they were provided with shelter, and timed to see how long it took for each shark to emerge from their refuge box into a new environment. The second behaviour test exposed each shark to handling stress, similar to handling by a fisherman, before releasing them again and observing how quickly they recovered.

The results demonstrated that each shark's behaviour was consistent over repeated trials, indicating ingrained behaviours rather than chance reactions. That is, some sharks were consistently bolder than others, and the sharks that were the most reactive to handling stress in the first trial were also the most reactive in a second trial.

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Sharks can be 'social or solitary'

By Jonathan Webb

Science reporter, BBC News

The most feared predators in the sea have individual personalities that affect how readily they socialise, according to a study by UK scientists.

Individual sharks, studied in groups of ten, showed consistent social habits - either forming groups with other sharks or finding camouflage on their own.

When a group was shifted into a new environment, individual sharks showed the same patterns of behaviour.

This is the first study to show that sharks have their own personalities.

The research was done in large tanks at the Marine Biological Association of the UK, in Plymouth, in collaboration with the University of Exeter. The findings appear in the journal Behavioural Ecology and Sociobiology.

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Do Snakes Have Personalities? – via Herp Digest

JANAKI LENIN, The Hindu, 9/28/10-   South Indian king cobras are quite different from Oriya ones. Even after years in captivity at the Madras Crocodile Bank, the Oriya kings were just as feisty as day one. I dreaded the days when Rom had to feed them. The southern snakes would stalk and pounce on the dead rat that Rom dangled enticingly in front of them. The Oriya snakes, however, would bite the tongs, plants, and boulders in the enclosure, and after they ran out of things to bite, grab the rat. Sometimes, they would even look at Rom’s shoes intently although he stood still.

These temperaments are not an artifact of captivity. In the Anamalais, Tamil Nadu, one tea estate labourer brought a large snake flailing inside a gunny sack, saying it was a rat snake. Inside was a hefty, 10-ft king cobra. Surprisingly, it had not bitten in self-defence while being caught and stuffed clumsily into the burlap.

One snake catcher in the mangrove forest of Bhitarkanika, Orissa, wasn’t so lucky; he was bitten on the nose by a wild king cobra. Even if he had been close to medical help, there is no anti-venom for king cobra bite in India. Without hesitating for a moment, he swung his machete and chopped his own nose off. It is possible the snake didn’t inject any venom, but had the man waited for the symptoms to develop, he might not have lived to tell the tale.

Pictures of many snake rescuers free-handling calm king cobras from the Western Ghats circulate on social networking sites. If these heroes tried a similar stunt with the feisty Oriya ones, they wouldn’t last a minute.

For centuries, mongoose-and-cobra fights have been staged by snake charmers. The cobras’ first line of defence, to sit majestically and menacingly with their heads up and hoods spread, doesn’t cut any ice with mongooses. We had always assumed the quick-to-tire reptiles were no match for the agile and swift mammals.

It was only recently, when a film crew used high-speed cameras, that we realised cobras strike at their tormentors from the defensive posture without opening their mouths; they were merely head-butting.

I haven’t found a credible explanation for their reticence to bite. Rom suggested, “Venom is expensive to produce. Snakes may want to use it as a last resort.”

I argued, “But this is a matter of life or death. If a cobra won’t use its venom when a mongoose goes for its jugular, when is a good time to use it?”

Despite these broad generalisations about species’ temperaments, there is variation among individual snakes.

A man showed up at our door once holding a healthy adult Russell’s viper in his bare hands. I was still collecting my wits, when he announced he had caught a baby python. Rom instructed in a calm voice, “Put it down slowly and gently.”

After he flipped the snake into a bag, he berated the ignorant man.

On another occasion, Rom’s six-year-old son Samir and his partner in mischief, Kali, brought home a bunch of saw-scaled vipers in their little hands.

“See dada, baby cat snakes,” said Samir.

Surprisingly and fortunately, the normally snappy vipers didn’t bite either of the two kids.

Are these just instances of good fortune? Why didn’t the snakes bite while being caught? Is it the easy confidence of the ignorant that protects them? Some say snakes sense nervousness and react by biting. I wonder if perhaps these individual snakes are calm by nature. Yet, many nervous and frightened cobras, Russell’s vipers, and saw-scaled vipers bite tens of thousands of people every year in India.

I asked Rom, “Do you think the personality of the individual snake determines whether an encounter with a human ends in a medical emergency?”

Rom scoffed, “How do you suggest we test if a venomous snake is a Type A personality?”

Young cricket characters shaped by 'song'

The experiences of youth can change the adult personalities of crickets, a new study has found.

Scientists discovered that juvenile males that did not hear a cricket chorus while young grew into more aggressive adults.

It suggests that the animals can pick up behavioural traits while young which then become fixed in adulthood.

The scientists believe that personality may play a crucial role in ecology and evolution.

The findings of the team from the University of California, Davis, US are published in the journal Animal Behaviour.

In conducting the experiment the team captured juvenile field crickets that had not yet developed a tympanum, the equivalent to an ear, which grows on the cricket's front legs.

"We isolated them all effectively before any of them could hear anything," said lead author Nicholas DiRienzo.

While one group of crickets were reared in silence, another were played a looped recording of five calling males.

"In the sound treatment there was a chorus of five different crickets playing back, calling, to mimic just what you would hear on a summer night, lots of different crickets calling and singing."

The silence was similar to the conditions experienced by juveniles hatching in spring when the cricket population tends to be at a low density, and hence quieter. Any juveniles born later tend to find a denser population of crickets, which is louder.

Continued:  http://www.bbc.co.uk/nature/19248230

Finches' personalities 'shown by head colour'

Gouldian finches have different personalities depending on the colour of their heads, researchers have found.

Scientists from Liverpool John Moores University and The Royal Veterinary College investigated the "highly sociable" Australian birds.

The team set the finches a series of behavioural tests to understand the purpose of their bright appearance.

They found that red-headed finches were more aggressive, while black-headed birds were bolder and took more risks.

The findings are published in the journal Animal Behaviour.

"Our idea is that the colour signals their behavioural tactics," said lead researcher Leah Williams.

She explained that the research also suggests that "bolder" black-headed finches may act as "leaders" in a group.

Gouldian finches are found in open, subtropical woodland and are known for their colourful plumage.

In the wild, the majority of the birds have black or red heads, although a very small number are yellow-headed.

When Gouldian finches first hatch "they're actually all an olive brown colour," Ms Williams told BBC Nature.

"After their first moult, when they're a couple of months old, that's when they get their colour."

Continued:  http://www.bbc.co.uk/nature/18297721

Insects Have 'Personalities' Too, Research On Novelty-Seeking Honey Bees Indicates

ScienceDaily (Mar. 8, 2012) — A new study inScience suggests that thrill-seeking is not limited to humans and other vertebrates. Some honey bees, too, are more likely than others to seek adventure. The brains of these novelty-seeking bees exhibit distinct patterns of gene activity in molecular pathways known to be associated with thrill-seeking in humans, researchers report.

The findings offer a new window on the inner life of the honey bee hive, which once was viewed as a highly regimented colony of seemingly interchangeable workers taking on a few specific roles (nurse or forager, for example) to serve their queen. Now it appears that individual honey bees actually differ in their desire or willingness to perform particular tasks, said University of Illinois entomology professor and Institute for Genomic Biology director

Gene Robinson, who led the study. These differences may be due, in part, to variability in the bees' personalities, he said.

"In humans, differences in novelty-seeking are a component of personality," he said. "Could insects also have personalities?"

Robinson and his colleagues studied two behaviors that looked like novelty-seeking in honey bees: scouting for nest sites and scouting for food.

Read on:  http://www.sciencedaily.com/releases/2012/03/120308143201.htm