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Nature's fortress: How cacti keep water in and predators out - Lucas C. Majure

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  • TEDEd Animation

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If you were a jackrabbit in the desert, you’d be glad to stumble across a cactus: the flesh of these plants is a water source for many animals. Known for their spines and succulent stems, cacti of all shapes and sizes have evolved to not just survive, but thrive, in some of the harshest desert climates on Earth. So how do they do it? Lucas C. Majure shares the prickly plant’s unique adaptations.

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About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here »

Meet The Creators

  • Educator Lucas C. Majure
  • Director Joseph Clark, Oh Studio
  • Narrator Addison Anderson
  • Composer Salil Bhayani, cAMP Studio
  • Sound Designer Amanda P.H. Bennett, cAMP Studio
  • Director of Production Gerta Xhelo
  • Editorial Director Alex Rosenthal
  • Producer Bethany Cutmore-Scott
  • Editorial Producer Elizabeth Cox
  • Content Associate Abdallah Ewis
  • Script Editor Emma Bryce
  • See more creators
Additional Resources for you to Explore
The Cactaceae show a number of adaptations for deserts, or otherwise dry, habitats. Given that dry habitats do not have to be in a desert, for instance a large rock surface becomes a very dry habitat even in a lush temperate forest, cacti can easily make their homes outside of deserts just as well as they do within them. They occur naturally in these dry habitats from Canada to Patagonia in southern South America. This distribution also includes the entire Caribbean region, where many species of cacti occur. See more about their distribution and evolutionary history here.

Several of the adaptations to these dry environments include the production of highly modified leaves in the form of spines, which also protect from the sun’s rays and herbivores, succulent tissue that enables them to store lots of water, the thick waxy cuticle overlaying the skin or epidermis, rain roots that quickly develop after even moderate precipitation, and CAM photosynthesis, which allows these plants to open their stomata at night, further reducing water loss. CAM photosynthesis has evolved in numerous plants that occur in these dry, or otherwise, water-limited habitats. See here the difference between different photosynthesis types.

All of these adaptations have given cacti an advantage over many other plants, and for these reasons, they are one of the most conspicuous elements of dry habitats across the Americas. Some of the most iconic cacti, such as the saguaro, Carnegia gigantea, are known from the Sonoran Desert in the western United States and northern Mexico. The prickly pear cacti of the genus Opuntia, which are the most widespread of all cacti, are often used by people as a food source, dye source, and for their medicinal and ornamental properties. So, cacti are very valuable to people, as well as to animals that use them in their natural environments.

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About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here »

Meet The Creators

  • Educator Lucas C. Majure
  • Director Joseph Clark, Oh Studio
  • Narrator Addison Anderson
  • Composer Salil Bhayani, cAMP Studio
  • Sound Designer Amanda P.H. Bennett, cAMP Studio
  • Director of Production Gerta Xhelo
  • Editorial Director Alex Rosenthal
  • Producer Bethany Cutmore-Scott
  • Editorial Producer Elizabeth Cox
  • Content Associate Abdallah Ewis
  • Script Editor Emma Bryce
  • See more creators

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