A look at how cacti are able to survive and grow in the harsh, dry desert environment. The spines on a cactus help to protect it from humans and animals. Its roots are spread out to collect water when it does rain and it stores water in its body for future use. An expert explains how a cactus can survive for years between rainstorms by living off the water it stores. He shows that a cactus which has been dead for eight months still contains water in its flesh.

First broadcast:
8 October 2007

This clip could be used as an introduction to a topic on plants or as part of a topic about water. After watching the clip, pupils could look at a variety of different cacti and, using some examples in the classroom, they can study the structure of the plant and look at the sharp protective whiskers. Research could be done on how much water a large cactus can hold. Further study could be done on deserts and a look at how other plants and animals survive.