Why can’t penguins fly?
Even the very smallest penguin,the fairy penguin,weighs 1 kg,which is about as much as a herring gull (银鸥). But herring gulls have a 1.4-meterwingspan,compared with just 32 centimeters for the fairy penguin. Water is 784 times denser (密度较大的) than air,and around 62 million years ago,penguins began making adaptations for swimming underwater. Their bones are filled with heavy bone marrow (骨髓)rather than air and they have much larger stomachs for making long fishing trips away from the nest.
How do squirrels find buried nuts?
It was once thought that they just used their noses to sniff out buried nuts and that the majority were never actually located. But a study at Princeton University showed that squirrels actually have a good memory and can build a map of the route from one hidden nut to the next.
Why don’t horses have toes?
Early horses such as Hyracotherium, which lived 55 million years ago, did have toes, but they were much smaller animals. For taller animals, extra weight at the end of their legs has a much bigger influence on their speed. A recent study at Harvard University, the USA, found that one broad hoof (蹄) is almost as strong as many smaller toes, but much lighter.
Do animals have blood types?
Yes, they do! As long as the animals in question have blood (not all do)then they will have species-specific “blood groups”. As with humans, these groups are determined by the structure of the blood based on the presence or absence of antibodies along with the make-up of the proteins that sit on the outside of red blood cells.
Humans are usually one of four main blood types. Thirteen types have been identified for dogs, eight for horses and three for cats.
【小题1】Why can’t penguins fly?| A．Because of their physical characteristics. | B．Because of their poor adaptation. |
| C．Because of their habits of swimming. | D．Because of their changing environment. |
| A．3. | B．4. | C．8. | D．13. |
| A．Squirrels find buried nuts by chance. | B．Horses are stronger without hooves. |
| C．All animals have their blood types. | D．An animal is a book with secrets. |
| A．Questions you may be interested in | B．Questions on the animal kingdom |
| C．Secrets to discover in nature | D．Knowledge around you |
