Why dolphins don’t like to swim with humans ?

Many of us would love to swim with dolphins but it seems the aquatic mammals don’t return the sentiment.

British experts have found that wild dolphins are suffering at the hands of well-meaning tourists eager to dive in alongside them.

A study of the bottlenose species living off the coast of Zanzibar found the animals were experiencing ‘incredible’ stress from packed pleasure boats.

Lead researcher Per Berggren, from the University of Newcastle, said: ‘The current situation in Zanzibar is unsustainable. The local community is dependent on tourism – and therefore the dolphins – but unless the activity is regulated, the animals will leave.

‘Our study found that whenever the tourist boats were present the dolphins were very unsettled and spent less time feeding, socialising or resting.

‘This has a negative impact, not only on individual animals, but on the population as a whole and long term it could be devastating.

‘The problem is that any change needs to be tourist-driven. Many visitors will pay drivers extra in tips to steer their boats in close, herding the dolphins so they can dive right in amongst them. Our message is, keep your distance and put the dolphins first.’

Around 150 bottlenose dolphins live along the south coast of Zanzibar, where dolphin-watching was introduced in 1992.

Tourism replaced traditional hunting practices which were previously endangering the sea mammals.

‘Abolishing the hunts was a major breakthrough and dolphin watching offered a humane, sustainable alternative,’ said Dr Berggren.

‘Unfortunately, without regulation, dolphin tourism brings with it its own challenges.’

The scientists watched the dolphins over a period of 40 days. They found that when tourist boats were present, the amount of their time dolphins spent resting dropped from 38 per cent to just 10 per cent.

The time they devoted to foraging and socialising also halved.

Meanwhile, time spent on swimming activity more than doubled from 33 per cent to 77 per cent and dominated dolphin behaviour during interactions with tourist boats.

‘Overall, the dolphins are using more energy than they are taking in because they aren’t resting or feeding as much but are swimming more as they try to avoid the tourist boats,’ said Dr Berggren, based at Newcastle University’s School of Marine Science and Technology.

‘Zanzibar is a wonderful place, the dolphins are incredibly interesting and between July and October there are also breeding humpbacks in the area.

‘I would recommend that anyone go there for a holiday and support the local community but act responsibly and ask operators to follow existing guidelines.’

The findings are published today in the journal Endangered Species Research.

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Why do we laugh?


The reasons we laugh, including “contagious” laughter, may be products of evolution.

Natural laughter is a two-part, spontaneous, response to humor, that has physiological, psychological, and physical benefits.

Most agree that we laugh when we find something to be humorous, yet different reasons exist for what we find to be humorous. Additionally, different things are humorous to us at different stages of life.

Laughter, a physiological response to humor, can be broken down into two parts.

The first is a set of gestures, and the second is the production of sound. The brain forces to conduct both responses simultaneously. From a physiological standpoint, a “sensor” in the brain responds to laughter by triggering other neural circuits in the brain, which, in turn, generate more laughter.

Oddly enough, laughter is an orderly response, and almost occurs “spontaneously” during pauses at the end of phrases, earning it the name the punctuation effect. Human beings are the only species capable of laughter, and the average adult does so approximately 17 times per day.

Good health is one of the many benefits of laughter. Laughter reduces our stress levels by reducing the level of stress hormones, and also helps us cope with serious illnesses.

Physiologically, laughter promotes healing, by lowering the blood pressure, and by increasing the vascular blood flow and the oxygenation of the blood.

Physical fitness stemming from laughter is a benefit known to few. Scientists estimate that laughing 100 times is equivalent to a 10-minute workout on a rowing machine, or to 15 minutes on a stationary exercise bike. The mere act of laughing exercises the diaphragm, as well as the abdominal, respiratory, facial, leg, and back muscles.

Another benefit of laughter is that it improves our over-all mental health. Pent up negative emotions, such as anger, fear, and sadness, can cause biochemical changes in our bodies that can produce a harmful effect.

Laughter provides a harmless outlet for these negative emotions, and provides a coping mechanism for dealing with difficult or stressful situations.

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Why do we yawn?

THE TRUTH IS that we don’t completely understand why people, or animals for that matter, yawn.

It’s widely assumed that yawning occurs because we are tired or bored or because we see someone else doing it, but there isn’t any hard evidence to support these beliefs.

Scientists do not purport to know all of the biological mechanisms of the yawn, but tend to agree that a yawn is an involuntary respiratory reflex, which regulates the carbon dioxide and oxygen levels in the blood.

Technically, a yawn is the reflex opening of the mouth followed by the deep inhalation and slow exhalation of oxygen.

The very act of yawning is but one of a number of involuntary reflexes controlled by the spinal and nerve centers.

Scientists speculate that the onset of a yawn is triggered either by fatigue, or by sheer boredom as, at those times, breathing is shallow, and little oxygen is carried to the lungs by the oxygen-toting cardiovascular system.

When one yawns, his or her alertness is heightened, as the sudden intake of oxygen increases the heart rate, rids the lungs and the bloodstream of the carbon dioxide buildup, and forces oxygen through blood vessels in the brain, while restoring normal breathing and ventilating the lungs.

This quite plausible theory of yawning falls short of explaining many aspects of yawning. Scientists explain away the “contagious” nature of yawning, that is when one person’s yawn triggers another nearby to yawn, as due to the power of suggestion, but are at a loss when attempting to explain why yawning occurs excessively in patients with lower brainstem damage or with multiple sclerosis.

Other unlocked mysteries include why fetuses in the womb yawn, when it is a well-known fact that they do not intake oxygen into their lungs until after live birth, or why individuals with high concentrations of oxygen in their blood streams yawn.

Until these questions are answered, do not assume that a person who yawns in your presence is bored with what you are saying, or suffers from exhaustion. Simply be pleased that he or she is not bored to death.

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