Everything you need to know about Dogs

 

Dogs have lived with people for more than 11,000 years. They may have started to stay near humans for food and warmth. Then people began to train dogs to work for them. They bred certain types of dog for herding and guarding other domestic animals, then for hunting and for companionship. Gradually, different types of dogs developed, but it was not until the end of the 19^th century that specific breeds were classified. Today, there are about 200 dog breeds throughout the world. They are more varied in their appearance and behavior than any other domestic animal.

Domestic Dogs 

All breeds of domestic dogs from the Great Dane to the Chihuahua are descended from the wolf and have inherited the wolf’s instincts. Like wolves, dogs are pack animals. They treat humans as a part of their pack, and can be trained to accept their owner as their pack leader, and to follow his or her commands.

Dog groups

 The people of ancient Egypt and western Asia were the first to breed distinct types of dog for different purposes. By Roman times, dogs were kept for much the same reasons as they are today. There are seven main groups- working, sporting, non-sporting, terriers, hounds, toys and herding.

Dog Groups

Dog Features

The wolf is designed to chase, capture, kill and eat its prey. It is agile, with strong legs for running long distances. Domestic dogs retain many of the features of a wolf, but through selective breeding now exist in any shapes, sizes and colors.

Coats: 

There are three main types of dog coats- long, short and wiry. Most breeds have an outer coat of guard hairs and an undercoat of shorter hair. They moult, or shed their fur, changing their coat in 

spring and autumn.

Long hair

Wiry hair

Short hair

Feet: 

Dogs walk on their toes rather than the soles of their feet. Their paw pads help with grip, as do their claws, which are non-retractable unlike the cats.

Senses: 

Dogs have highly developed senses of hearing and smell. They use these in communication and to track down their prey. The police use dogs to sniff out explosives, criminals, and drugs. The dogs can see well in the dark and are good at seeing movement in the distance.

Reproduction

A female dog is pregnant for about nine weeks, and then gives birth to several puppies known as a litter. At birth, puppies are blind and deaf. Their eyes open at about 10 to 12 days and they are able to hear at 13 to 17 days old. Teeth start to grow between three and five weeks of age. 

At one week old, a puppy spends most of its time sleeping and feeding by suckling from its mother.

At two weeks old, the puppy takes its first wobbling steps and begins to explore. Its eyes are now open and it can hear.

At three weeks old, the puppy may start to eat solid food. At first, its mother will regurgitate meat for it.

At six weeks old, the puppy no longer feeds from its mother. It can soon be taken away from her to a new home. 

Everything you need to know about Cats

Domestic cats are related to wild cats, such as lions and tigers, and they are able to fend well for themselves. They are excellent hunters, and their eyes, ears, nose, and whiskers are well adapted for their natural preference for hunting at night. Cats are affectionate and respond well to humans. They are domesticated about 4,000 years ago to keep people company and destroy pests.

There are more than 100 recognized breeds of domestic cats. They are distinguished mainly by their body shape. People started to breed cats for their looks between 100 and 150 years ago.

 

Types of Cats

Fur

Cats can be divided into long haired and short haired breeds. Fur is of various textures. Common coat colors are grey-blue, white, red, and mixtures of these, such as silver and lilac.

Fur Texture

Head shapes

Cat head shapes range from large and round, like that of the British short-hair, to wedge-shaped, like that of the Siamese. Some breeds have special characteristics, such as the Scottish fold, which has the tip of its ears bent forward.

Claws

Cats use their claws to defend themselves and to climb. At other times, the claws are drawn in, or retracted, for protection. They are covered by a bony sheath that is an extension of the last bone of each toe and fit inside pockets in the skin.

Claws working mechanism

Senses

Cats can see well in low light and can focus on small objects a long way away. Their super sensitive hearing picks up sounds that we cannot hear and can also take in two sounds at once, such as mouse in a thunderstorm. Their ears are funnel-shaped to draw sounds inside the ear. Whiskers are sensitive to touch. Cats use them to feel their way in the dark, and to measure whether spaces are wide enough for them to go through. Sense of taste is important for distinguishing any food that may be harmful.

A cat’s pupils expand enormously in the dark to let in as much light as possible. A layer of cells at the back of the eyes, called the tapetum, reflects light back into the   eye which helps cats see in the dark. Cats rely more on eyesight than smell when hunting. They have the largest eyes in relation to their size of any animal.

Cat's eye cycle

Balance

A cat’s long flexible tail helps it to balance. Cats will almost always land on their feet, even when falling from a great height. They have very quick reflexes and can twist and turn their body the right way up in a fraction of a second.

A cat balancing

Grooming

Cats are very clean animals and spend at least an hour a day grooming, using their tongue as a ”comb”. The tongue has tiny hard spines, called papillae, on its surface. The licking helps to keep the fur clean and waterproof, and also spreads the cat’s scent all over its body.

A cat grooming itself

Kittens

Cats have an average of four or five kittens in a litter. Kittens love to stalk, chase, and pounce on things. This helps to make them strong, and develops the skills they will need as adults. 

A Litter

Black Death: The Bubonic Plague

   

 

In the 14^th century, a deadly epidemic swept across the world. The Black Death, as it became known, was bubonic plague, a terrible disease that begins with fever, causes agonizing black dwellings in the glands, and finally leads to death, usually within a few days of infection. Millions of people died. Terrified people fled infected areas and carried the plague with them. In towns the doors of plague carriers were marked with crosses to warn others to keep away. The dead were collected in carts and buried in mass graves. In Europe about one-third of the population died; a similar number probably died in Asia.

Burying in mass graves

Progress of the plague

The Plague reached the Black Sea from Asia in 1346. From there, it was carried by Italian traders to ports on the Mediterranean. It then spread up rivers and land routes into northern Europe. By 1350, most of Europe was infected.

Some areas, such as Poland and Milan, escaped the Plague, but the reason for this is still a mystery.

Disease Carriers

The Plague Cycle

 

Plague is caused by a bacterium that lives on rodents. The disease was caught by black rats in Asia, which then colonized ships to Europe and spread the disease among people there. An infected person could also pass the plague through the air, by coughing.

Plague bacterium: The bacterium is also called Yersinia pestis, after the Swiss biologist Alexander Yersin, who discovered it. It is common in wild animals such as field mice, marmots and ground squirrels.

 

Flea carriers: The plague bacterium lives in the digestive system of a flea, and causes a blockage there. When the flea feeds, the blockage makes it vomit the newly eaten blood back onto its host, along with plague bacteria, which then infects the host.

Animal carriers: The black rats lived in towns and on ships and scavenged in food stores and rubbish heaps. Rats carry fleas, and when plague-carrying rats died of the disease, their fleas searched for other hosts. If these new hosts were people, they, too, caught the plague.

Human carriers: The plague turned into an epidemic so rapidly because human travellers helped spread it. Mongol nomads and Asian merchants carried it across Asia. The traders of the great Italian cities, such as Genoa and Venice, carried it around Europe in their ships.

Effects of the Plague

The disease was so widespread that many left their families took to the road to try to escape death. Some thought the plague was God’s punishment for the sins of the people, and mercilessly whipped themselves in the streets to show repentance.

Whipping to show repentance

Labour: By the end of the 14^th century, the smaller population of Europe meant that life was better for those who had survived. Because there were fewer peasants, they got higher wages and there was more food to go around. But recurring peasant rebellions showed that they still had grievances.

 

Chantries: People often left money for masses to be said for their souls. These masses were said in special chapels inside churches known as chantries. This chantry is at Winchester, England.

Population Decline: When Pope Clement VI asked how many people had died from the plague, he was told at least 20 million people in Europe, and 18 million in Asia. In comparison, around 8 million soldiers died in World War I.

Tombs: During the plague, people faced death every day. Death is often realistically shown on 14^th-century tombs, where images of skeletons of decaying corpses are common.

Dealing with the plague

 

Some people tried to fend off the plague by using herbal remedies, fumigation, bleeding by leeches, and even bathing in urine. A 14^th-century poem, called The Dance of Death (which states that death comes for people of every rank) was often enacted and painted, to remind people that death and the plague could strike at any time.

The Dance of Death