All baby mammals except monotremes (see strange mammals) are born from their mother’s body, but most other creatures hatch from eggs.
Most creatures hatch long after their parents have disappeared. Birds and mammals, though, usually look after their young.
Most birds feed their hungry nestlings until they are big enough to find food for themselves.
Some small birds may make 10,000 trips to the nest to feed their young.
Cuckoos lay their egg in the nest of another, smaller bird. The foster parents hatch it and look after it as it grows. It then pushes its smaller, foster brothers and sisters out of the nest.
Mammals nurse their young (I hey feed them on the mother’s milk).The nursing period varies. It tends to be just a few weeks in small animals like mice, but several years in large animals like elephants.
Many animals play when they are young. Playing helps them develop strength and co-ordination, and practise tasks they will have to do for real when adults.
When they are young, baby opossums cling all over their mother as she moves around.
Some baby animals, including baby shrews and elephants, go around in a long line behind the mother, clinging to the tail of the brother or sister in front.
Crows use at least 300 different croaks to communicate with each other. But crows from one area cannot understand crows from another one.
When two howler monkey troops meet, the males scream at each other until one troop gives way.
The male orang-utan burps to warn other males to keep away.
Dogs communicate through barks, yelps, whines, growls and howls.
Many types of insect communicate through the smell of chemicals called pheromones, which are released into the air from special glands.
Tropical tree ant species use ten different pheromones, combining them with different movements to send 50 different kinds of message.
Orang-utans are shy and seldom seen. However, they may be heard occasionally — making burping noises to scare off other males!
The black mamba of Africa can race along at 25 km/h with its head raised and its tongue flickering.
A viper’s venom kills its victims by causing their blood to clot. Viper venom has been used to treat haemophiliacs (people whose blood does not clot well).
The pit vipers of the Americas hunt their warm-blooded victims using heat-sensitive pits on the side of their heads (see animal senses).
Fruit bats are susceptible to heat stroke, so to keep themselves cool, some lick themselves all over and fan cool air at their bodies with their wings.
The oryx has special blood vessels in its nose to keep its blood temperature low in the desert heat.
Large-eared desert species such as fennec foxes use their ears as radiators to get rid of body heat.
The desert bighorn sheep draws air over a thickly veined area of its throat to cool its blood.
Wallowing in mud keeps pigs cool and protects their skin from the sun.
A hippos’ skin exudes a red, lacquer-like substance to protect it from sunburn.
During hot spells, kangaroos lick their wrists a lot, so that the evaporation of the saliva causes cooling.
Indian zebu cattle have more sweat glands than western cattle, and can maintain a lower body temperature, making them common in warm countries such as China, Africa and South America.
The eland’s temperature can rise several degrees without causing sweating, allowing it to conserve 5 litres of water daily.
After feeding their young, mother bats often leave them in the heat of the cave and perch near the cooler entranc
Gliding mammals include the flying squirrels of America and Asia, the scaly-tailed squirrels of Africa, and the marsupial gliding possums of Australia.
The Australian feather-tailed glider is the smallest gliding mammal, weighing just 12
Gliding mammals achieve their glides by means of a hairy membrane called a patagium that joins the fore and hind limbs, and acts like a parachute.
The Southeast Asian colugo’s glide membrane stretches from the neck to fingers, toes and tail-tip.
When flying squirrels come in to land on a tree trunk, they brake by turning their tail and body under, like the landing flaps on an aircraft’s wing.
Africa’s scaly-tailed flying squirrels live in colonies of up to 100, and glide from tree to tree after dark.
The colugo (also known as a flying lemur) is about the size of a domestic cat. It has sharp claws for climbing and mottled fur for camouflage.
Australia’s gliders feed on sap and gum, biting through tree bark and lapping up the sweet liquids.
Some flying squirrels, when they land, quickly move to the opposite side of the tree trunk to avoid predators.
The colugo is virtually helpless on the ground.
The southern flying squirrel fluffs out its tail and uses it as a rudder in mid-air.
The longest glide by a gliding mammal ever recorded was 450 m by a giant flying squirrel
Some animals cope with the cold and lack of food in winter by going into a kind of deep sleep called hibernation.
During hibernation, an animal’s body temperature drops and its heart rate and breathing slow, so it needs little energy to survive.
Small mammals such as bats, squirrels, hamsters, hedgehogs and chipmunks hibernate. So do birds such as nighthawks and swifts.
Reptiles such as lizards and snakes go into torpor whenever the temperature gets too low. This is a similar state to hibernation.
Butterflies and other insects go into a kind of suspended animation called diapause in winter.
The pika (a small lagomorph) makes haystacks from grass in summer to provide food for the winter.
Many mammals survive cold winters by hibernating. Some, like this Arctic fox, will sleep for a few days at a time when there is little food to be found.
Bears go to sleep during winter, but not all scientists agree that they go into true hibernation.
Squirrels bury stores of nuts in autumn to feed on during winter. They seem to have remarkable memories, as they can find most stores when they need them.
Beavers collect branches in autumn and store them next to their lodges so that they can feed on the bark during the winter months.