Giraffes surprise biologists yet again

New research has highlighted how little we know about giraffe behaviour and ecology, according to Science Daily.

It is commonly accepted that group sizes of animals increase when there is a risk of predation, since larger group sizes reduce the risk of individuals being killed, and there are 'many eyes' to spot any potential predation risk.

Now, in the first study of its kind, PhD student Zoe Muller has found that this is not true for giraffes, and that the size of giraffe groups is not influenced by the presence of predators.

Chimpanzees 'keep their beds cleaner than humans' because they build complex tree nests out of branches and leaves which contains less bacteria than most households

Chimpanzees keep their beds cleaner than humans, scientists have discovered.

The great apes build complex tree nests out of branches and leaves in which they sleep. And they set an example the average human teenager would find tough to follow, according to Daily Mail.

In fact chimp forest nests contain fewer body bacteria - such as those shed from the skin - than beds in most human households.

PhD student Megan Thoemmes, who led a team collecting swab samples from 41 chimpanzee nests, found the chimp nests had a much greater variety of bugs - a finding that was not unexpected in tropical forests.

However, they were far less likely to harbour ‘dirty’ bacteria from the mouth, skin or elsewhere in the body.

‘We found almost none of those microbes in the chimpanzee nests, which was a little surprising,’ said Ms Thoemmes.

Scientists train spider to jump on demand to discover secrets of animal movement

Scientists have unlocked the secrets of how some predatory spiders catch their prey whilst hunting by successfully training one to jump different distances and heights for the first time, according to Science Daily.

The study, conducted by researchers, is the most advanced of its kind to date and first to use 3D CT scanning and high-speed, high-resolution cameras to record, monitor and analyse a spider's movement and behaviour.

Crocodiles listen to classical music in MRI scanner

What happens in a crocodile's brain when it hears complex sounds? An international research team headed by Dr Felix Ströckens has provided the answer to this question. In a first, the researchers examined a cold-blooded reptile using functional MRI. They were thus able to determine that complex stimuli triggered activation patterns in the crocodile's brain that are similar to those in birds and mammals -- a deep insight into evolution, according to Science Daily

How do marine mammals avoid the bends?

Deep-diving whales and other marine mammals can get the bends -- the same painful and potentially life-threatening decompression sickness that strikes scuba divers who surface too quickly. A new study offers a hypothesis of how marine mammals generally avoid getting the bends and how they can succumb under stressful conditions, according to Science Daily.

The key is the unusual lung architecture of whales, dolphins and porpoises (and possibly other breath-holding diving vertebrates), which creates two different pulmonary regions under deep-sea pressure, say researchers.

"How some marine mammals and turtles can repeatedly dive as deep and as long as they do has perplexed scientists for a very long time," says Michael Moore, co-author of the study. "This paper opens a window through which we can take a new perspective on the question."

When air-breathing mammals dive to high-pressure depths, their lungs compress. That collapses their alveoli -- the tiny sacs at the end of the airways where gas exchange occurs. Nitrogen bubbles build up in the animals' bloodstream and tissue. If they ascend slowly, the nitrogen can return to the lungs and be exhaled. But if they ascend too fast, the nitrogen bubbles don't have time to diffuse back into the lungs. Under less pressure at shallower depths, the nitrogen bubbles expand in the bloodstream and tissue, causing pain and damage.

Marine mammals' chest structure allows their lungs to compress. Scientists have assumed that this passive compression was marine mammals' main adaptation to avoid taking up excessive nitrogen at depth and getting the bends.