Hi, I'm Liam and today I'm going to tell you about mammals. That's right, the vertebrates that range from the gigantic blue whale, to us (humans) to the tiny little creatures we'll be focusing on more.
History of the mammal
Mammals are roughly 250million years old and came from reptiles. The first ever one was like a shrew (it's below). It ate insects from ferns.
The largest mammal is the blue whale. Measuring at up to 30 metres long, it needs water to support it. It eats 3.6kg a day of krill. The smallest mammal is the etruscan shrew, living in the Medditerrainean and in Asia. At 4cm in length it is the size of two bees! It weighs 1.8 grammes. The Bowhead Whale can live for over 200 YEARS . One has been alive for 211 years. House mice only live for one year in the wild. Elephhants can be pregnant for over one and a half years! The opossum, however, can have a pregnancy lasting only 13 days.
Mammals are warm-blooded. They have fur and drink milk as babies. There are only five species that lay eggs, the duck-billed platypus and four echidna species, all of which live in Oceania. Mammals live in every continent in the world. Some can fly, some live in the water but most live on land. A blue whale's pregnancy is 10-12 months long. Bats are the only mammals that can fly. There are over five thousand species of mammal! There are roughly 130 billion mammals on earth. That's not much. for reference, there are over 10000000000000000000 or 10 quintillion instects on earth.