The animal kingdom is made up of living things that cannot produce their own food (through the process of photosynthesis) and can be divided into two groups. Those with backbones (vertebrates) and those without backbones (invertebrates).
- There are about 1.25 million species of animals that we have so far identified.
- Scientists think there may be anything between 10 and 30 million more species yet to be discovered.
- The blue whale is the largest known animal and can grow up to about 30 metres/100 feet in length and weigh some 170 tonnes. Their heart is about the size of a motor car.
- The smallest animal is open to some discussion. Protozoa are considered by some scientists to be animals and by others not to be. The Megaphragma caribea or Fairyfly grows to between 0.10mm and 0.17mm so many consider this to be the smallest animal.