All living things need water – it is needed for lots of important things that help to keep plants, animals, fungi and bacteria alive. Where my family lives, we are lucky to have clean water to drink from the taps in our house and at the places we go to school and work. But some people and animals have to travel long distances to find water that is safe to drink.
My children were drinking water with their lunch: “What do sea creatures drink?” asked my 5-year-old. “Whales eat krill but they spit all the water out. So what do they drink?”
My 9-year-old suggested that perhaps sea creatures don’t need to drink because their food is already wet. “Maybe the krill is moist enough?” she wondered.
It got us thinking about why water is so important for life and how living creatures get the water they need.
Water is one of the most important chemicals on our planet. It is made up of hydrogen and oxygen, and it is needed for lots of different processes that keep living things alive.
For example, plants need water to make energy from sunlight, to get the oxygen they need to stay alive, and to stop their leaves and stems becoming droopy and floppy. You can find out more about how plants work in my post on ‘do plants breathe?‘
Animals need water too. Some animals (like humans) drink water or get it from their food and use it to make their body fluids (like blood) and digest food. And some animals (like frogs) live near water because they need it as part of their lifecycle.
And some animals (like fish and whales) live their whole lives in water. Their bodies need water too! Some kinds of fish get water into their bodies through their skin and gills, and some of them drink the water they swim in. Whales drink sea water – even though it’s too salty for humans to drink! So, sea creatures drink or absorb water from their habitat.
You can find out more about sea creatures on the National Geographic Kids website.