Succulent plants
All living organisms have problems with water shortage in arid areas. Animals can hide from the sun during the day, but plants have to stay where they are and they also need sunlight for energy to live.
Main content
Plants are almost always present, even in the driest deserts, and they are adapted to survive almost entirely without water by saving between the few rains. Many such plants have rounded succulent leaves or stems - they are called succulents and store water in specialised tissue.
Succulents have adaptations to reduce evaporation, mainly by exposing as little surface as possible (absence of leaves, rounded leaves or stems, storing water underground), but also by being hairy, or having an impermeable surface. Many are adapted to only grow and/or flower and set seed immediately after rain. Then they save until next time. Some also have very deep roots that reach water far below the soil surface.
At the same time, the plants become very attractive to animals, as food and as a source of water. If the plants have thorns or spines (cacti, euphorbia) or are poisonous, foraging animals may be deterred.
There are succulents in many unrelated plant groups. Almost all cacti are succulents, but not all succulents are cacti! Succulents are not only found in hot, dry areas, but can be found in any place which is dry, at least occasionally, even in alpine areas.