Photos

Yaaaaaaaaawnnn....

Well, hope this wasn't your reaction upon looking at this photo - the photo that made me think about why we also tend to yawn more on a hot sunny day?

I found information on the Web* that say that there are varios reasons why we yawn:

1. The deep inhalation during a yawn is means of preventing alveolar collapse within the lung.
2. The deep inhalation while yawning stretches type II alveolar pneumocytes, which release the surfactant dipalmitoylphosphatidylcholine (DPPC) into the layer of fluid on the alveolar surface.
3. A means of cooling the brain.
4. An action used as an unconscious communication of psychological decompression after a state of high alert.
5. An excess of carbon dioxide and lack of oxygen in the blood.
6. A way of displaying (or indicative of) apathy.
7. Tiredness.
8. A means of equalizing middle ear pressure, which can be triggered by another's yawning.

*

Interesting Yawning Facts:

* The average yawn lasts about six seconds.
* Your heart rate can rise as much as 30 percent during a yawn.
* 55 percent of people will yawn within five minutes of seeing someone else yawn.
* Blind people yawn more after hearing an audio tape of people yawning.
* Reading about yawning will make you yawn.
* Olympic athletes often yawn before competition.

Photo info:
- taken in Friguia Zoo earlier this year