Pocket Genius Science: The living world – Natural history facts

Facts At Your Fingertips: The living world – Natural history facts


  • The oldest living thing on Earth is the giant seagrass that grows in the Mediterranean Sea. Some of it may be 200,000 years old
  • The longest-lived animal is the clam, which can live for more than 400 years. Of animals that move around, the bowhead whale may live the longest—one whale was recorded to have lived for 211 years.
  • The oldest trees on Earth are bristlecone pines, some of which are more than 5,000 years old.
  • The oldest group of living things still around today are archaea (bacterialike single-celled life-forms). They evolved more than 3 billion years ago, soon after the very first life-forms appeared on Earth.
  • The earliest animals on Earth were sponges that lived in the oceans more than 700 million years ago. The first land plants appeared 425 million years ago. Dinosaurs appeared 230 million years ago.
  • The heaviest bird is the ostrich, weighing up to 345 lb (156 kg), which is too heavy to fly. The heaviest flying bird is the great bustard, which weighs 46 lb (21 kg). The lightest bird is the bee hummingbird, which weighs just 1/10 oz (2 g).
  • The largest insect in the world is the giant weta, which weighs 21/2 oz (71 g). The smallest insect is the parasitic wasp Dicopomorpha echmepterygis, which is less than 1/100 in (0.2 mm) long.
  • The largest spider is the goliath birdeater tarantula, with a leg span of 12 in (30 cm). The smallest spider is Patu marplesi, measuring 17/1000 in (0.43 mm)—the size of the period at the end of this sentence.
  • The largest reptile, the Nile crocodile, grows up to 20ft (6 m) long. The smallest reptile, a dwarf chameleon, is about 1 in (28 mm) long.
  • The biggest amphibian is the Chinese giant salamander; it can grow up to 6ft (1.8 m) long. The smallest amphibian is Paedophryne amauensis, a tiny frog from Papua, New Guinea. At ¼ in (7 mm) long, it is also the world’s smallest vertebrate.
  • The smallest mammal is the hog-nosed bat, also called the bumblebee bat, which weighs just 1/10 oz (2 g).
  • Spores of rod-shaped bacteria that are 250 million years old have been brought back to life by scientists.
  • Humans first evolved in Africa about 200,000 years ago. They left Africa to spread across the world about 90,000 years ago.
  • Dinosaurs were once thought to have died out 66 million years ago. But scientists now think that birds are their direct descendants and should be thought of as living dinosaurs, so the dinosaurs really did not die out at all.


  • The biggest animal that has ever lived on Earth is the blue whale, a mammal that can grow up to 100ft (30 m) and weigh 200 tons (180 metric tons). Possibly the smallest animal is the tardigrade, or water bear. This invertebrate can be just 1/200 in (0.1 mm) long.
  • The biggest fish is the whale shark, which can grow to 60ft (18 m). The smallest fish is Paedocypris progenetica, which is just 3/10 in (7.9 mm) long.


  • The giant moa was the tallest bird ever, standing 12ft (3.6 m) tall. It lived in New Zealand and became extinct about 500 years ago due to hunting by humans.
  • The South American short-faced bear, which lived about 1 million years ago, weighed 1.7 tons (1.5 metric tons) and stood more than 11ft (3.4 m) tall when standing on its hind legs. It was twice the size of a polar bear.
  • The steppe mammoth stood 13ft (4 m) tall. Its tusks could grow to more than 16ft (5 m) long. It lived in Siberia 500,000 years ago.
  • Josephoartigasia monesi was a giant rodent that lived in South America 2 million years ago. It was the size of a small car, measuring 10ft (3 m) long and weighing about 1 ton.
  • Argentinosaurus was one of the largest dinosaurs, measuring 100ft (30 m) from head to tail and weighing more than 77 tons (70 metric tons). It laid eggs the size of soccer balls.
  • Meganeura was a giant dragonflylike insect that lived 300 million years ago. It had a wingspan of more than 100ft (60 cm).

Scientists think there are about 8.7 million species of living thing on Earth. About 90 percent of them have yet to be discovered!