The animal kingdom is dotted with species that give birth to spotted young, from deer to birds and fish. Even species that we don’t typically associate with spots, such as lions, wear the pattern as babies, only to lose it later in life.

But what purpose do these spots serve, and why do only some species seem to have them? Kiyoko Gotanda, a biologist at Brock University, said it is likely so common because spots are useful in keeping babies hidden from their enemies.

Spotted young tend to be more common in species that live in habitats with some three-dimensional structures, Gotanda noted, and less common in environments that are uniform or featureless. Indeed, baby seals born on pack ice are pure white, and develop spots only when they leave the ice for rocky beaches. But in habitats with some cover, spots function as the sunlight passing through leaves or tall grass, making an animal hard to be discovered in its background.

“It is not as overt a pattern as something like a stick insect that becomes something else entirely, which can be clearly identified. But spots do create these three-dimensional effects that help some species hide better,” said Gotanda.

In other rarer cases, spots actually help babies stand out. Young garibaldi — orange marine fish found along the coast of California and Mexico — have bright-blue spots that advertise their lowly status to highly territorial (有地盘意识的) males. As the fish grow and start to engage in the social order, their spots fade.

In fact, many species grow out of their spots, and the reasons aren’t entirely understood. According to Gotanda, patterning is typically considered more energetically costly to produce than a single, solid color. But spots don’t take a lot of energy to grow and maintain at least in the case of white spots. There must be other reasons to explain their loss, he said.

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.

A group of researchers studying the behavior of Amur tigers, also known as Siberian tigers, have found that they have different “personality” types that help them survive and raise their baby tigers.

According to the previous investigation, Amur tigers are definitely the largest cuts in the world. They live in vast forests in wildness areas of eastern Russia and in protected areas of northern China. There are about 400 of these tigers left in the wild, although there are probably hundreds more living in zoos or reserves.

The researchers based the study on a human test called “The Big Five”, which scores people on five personality features. They asked feeders working with 248 cats in two shelters to spy on the tigers and give an account of their personalities. The results divided the tigers into two groups, which the researchers described as having either “majesty” or “steadiness”. Tigers in the majesty category were those that appeared “dignified (高贵的) and ambitious”. The tigers in the steadiness category were “sincere and tolerant”.

Majestic tigers had a higher social status, spent more time hunting live animals, and mated and ate more. The steady tigers seemed gentler and loving toward one another. Rosalind Arden, co-author of the study, said, “It’s pleasant to see that you don’t have to be dominant, fierce, competitive, and aggressive in order to succeed as a tiger, which doesn’t correspond with people’s traditional insights into tigers.”

There were female and male tigers in both categories. In fact, female Amur tigers are rare and feel exhausted after giving birth to baby tigers so that fathers often help raise the baby tigers. Having a steady personality, especially for male ones, could play a significant role in the relatively long amount of time — two to three years — that baby tigers stay with their parents. The researchers say both personalities have advantages that help the tigers survive threats, including loss of habitat and hunting. The team hopes the study will encourage more support from all walks of life in a bid to guarantee the tigers’ conservation.