Weird Science

with Herald science writer Jamie Morton: @ jamienzherald

Why are we scared of spiders?

Most of us have never come across a poisonous spider in the wild — we only have two venomous species in New Zealand and bites are rare.

Yet the thought of a spider crawling up our arm is enough to send a shiver up our spine, and in developed countries, 1 to 5 per cent of the population have a phobia of creepy- crawlies.

Now, researchers think this inherent aversion stems from evolution.

German and Swedish scientists say even in infants as young as six months, a stress reaction is evoked when they see a spider or a snake.

“When we showed pictures of a snake or a spider to the babies instead of a flower or a fish of the same size and colour, they reacted with significantly bigger pupils,” said study leader Stefanie Hoehl, of Germany’s Max Planck Institute for Human Cognitive and Brain Sciences.

“In constant light conditions, this change in size of the pupils is an important signal for the activation of the noradrenergic system in the brain, which is responsible for stress reactions.

“We conclude that fear of snakes and spiders is of evolutionary origin.

“Similar to primates, mechanisms in our brains enable us to identify objects as ‘ spider’ or ‘ snake’ and to react to them very fast.”

This inherited stress reaction in turn predisposes us to learn these animals as dangerous or disgusting — something that could lead to a phobia if combined with other factors.

Introducing . . . RoboBee

We’ve seen tiny robots that can fly, stick to walls and dive into water.

Now, get ready for a hybrid RoboBee that can fly, dive into water, swim, propel itself back out of water and safely land.

Floating devices allow this multipurpose air- water microrobot to stabilise on the water’s surface before an internal combustion system ignites to propel it back into the air.

This RoboBee, which is 1000 times lighter than any previous aerial- to- aquatic robot, could be used for numerous applications, from search- and- rescue operations to environmental monitoring and biological studies.

“This is the first microrobot capable of repeatedly moving in and through complex environments,” says Yufeng Chen, a graduate student from Harvard University’s John A Paulson School of Engineering and Applied Sciences.

“We designed new mechanisms that allow the vehicle to directly transition from water to air, something that is beyond what nature can achieve in the insect world.”

Discovered: T. rex’s cousin

A team of scientists has discovered the first evidence of a huge carnivorous dinosaur that roamed Southern Africa 200 million year ago.

The researchers have found several three- toed footprints measuring 57cm long and 50cm wide in Lesotho, a small country in Southern Africa.

This means the dinosaur would have had a body length of about 9m and be a little less than 3m tall at the hip.

That is four times the size of a lion, the largest carnivore in Southern Africa.

The footprints belong to a new species, named Kayentapus ambrokholohali, which was part of the group of dinosaurs called megatheropod, which include Tyrannosaurus rex.

“The latest discovery sheds new light on the kind of carnivore that roamed what is now Southern Africa,” says Dr Fabien Knoll, of the University of Manchester.

“That’s because it is the first evidence of an extremely large meat- eating animal roaming a landscape otherwise dominated by a variety of herbivorous, omnivorous and much smaller carnivorous dinosaurs.

“It really would have been top of the food chain.”

The footprints date back to the Early Jurassic epoch, when it was thought the size of most theropod dinosaurs was much smaller. It was only much later, in the Jurassic and Cretaceous periods, which started 145 million years ago, that truly large forms of theropods, such as T. rex, appeared in body and trace fossil records.

“This discovery marks the first occurrence of very large carnivorous dinosaurs in the Early Jurassic of southern Gondwana — the prehistoric continent which would later break up and become Africa and other land masses,” says Dr Lara Sciscio, a postdoctoral research fellow at South Africa’s University of Cape Town.