Essay #15-Caves and Deserts: Life in the Extreme

Caves and Deserts are center stage in the video series Planet Earth, produced by BBC and narrated by Sir David Attenborough. In the episode Caves, the cameras shine light in places where there has never been light before. Caves comprise 10% of the earth’s surface and are among the least explored places on earth. They contain a variety of animal life uniquely adapted to cave life. The biggest challenge of cave life is finding a regular and reliable source of food. The 400 meter deep Cave of Swallows in Mexico contains an unusual variety of worm that lives on the cave ceiling. To catch their insect prey, these worms secrete silk lines from their bodies and emit light that shines like a blanket of stars attracting and trapping their food. Bats are the most well known cave dweller and bring in food for other cave creatures through their droppings.

The episode, Deserts, shows that life there can be just as extreme as in caves. The Gobi desert in Mongolia reaches temperatures of lows of -40 degrees and highs of 122 degrees F. The search for water dominates the lives of desert animals. It snows in the Gobi desert, but the air is so dry it will never melt, but simply evaporates. In order to get water, the camels that live in this harsh climate chew the snow chunks. Africa has the largest desert, the Sahara, which is larger in size than the United States. Most desert creatures are nocturnal, however kangaroos survive Australia’s life threatening desert temperatures by licking their forearms to cool down their blood.

Life can thrive and exist in surprising and extreme places. As this series shows, nowhere is the existence of life more surprising than in the extremes of caves and deserts.

Advertisement