The subject of many myths and hunters’ tales, the jaguar is the largest wild cat native to the Americas. It is now extremely rare outside captivity as the result of being hunted for its attractive skin.
Jaguars live in a variety of habitats, from dense jungle and scrubland to reed thickets and shore-line forests. They will even live in open country provided the grass and rocks offer sufficient cover for hunting and a reliable supply of water is available.
Where do jaguars live?
Jaguars were once found everywhere from Arizona to Argentina, but ruthless hunting has wiped them out from most of their range, and reduced them greatly elsewhere.
In many countries, rapid expansion of forest clearing to provide pastures for beef cattle and to build new settlements has finished what the hunters began. Jaguars are said to still be common in the upper basin of the Orinoco, Venezuela, but almost everywhere else they are in danger of extinction. In fact there are believed to be less that 200 jaguars left in the whole of Argentina! At this rate, the only flourishing population of jaguars left will be those held by world’s zoos.
Jaguars have a reputation for being man-eaters, and there are many hunters’ tales of men being followed for mile after mile through the forest by a solitary jaguar, which eventually fades away as silently as it appeared. This suggests that the animal was escorting the men off from its territory. If the jaguar had been hunting them, it would have had plenty of opportunities to attack and kill its intended prey.
Adult jaguars are solitary animals, except during the breeding season when a male and female stay together for a short while in order to mate. The young jaguars stay with their mother for the first few years of life before leaving the family to find hunting territories of their own.
The size of the jaguar’s territory depends on the availability of food. Where food is plentiful – as you would expect in an area of undisturbed forest – a jaguar should be able to feed itself from a circular area of about 5km in diameter. Where food is scarcer – perhaps because the forest has been cleared – a jaguar may need a territory of 500sq km, 30 times larger!
What do Jaguars eat?
Although jaguars are good climbers, they hunt mainly on the ground at night. They will however, climb trees in order to lie and wait for prey.
The jaguar can over short distances rapidly, but it will tire quickly. Therefore its successful kills rely on both surprise and getting sufficiently close to unsuspecting prey.
Its main food consists of forest animals – varying in size from mice to deer. However the jaguar is also an excellent swimmer, able to catch frogs, fish, turtles and even small alligators!
The jaguar is especially skilled at catching fish, which it achieves by lying motionless on a rock or overhanging branch, then flipping the fish out on the bank with its paw.
Jaguars will also take domestic animals – particularly where the forest has been cleared for farmland.
After the kill, jaguars will drag their pray into cover before eating it, often burying part of the carcass to finish it off later.
Jaguar breeding
Very little is known about the family life of wild jaguars. For many years they have been hunted for their fur. In fact, during the 1960’s over 1000 were shot every year in the Brazilian Amazon jungle. Hunters became experts at finding and killing them but paid little attention to their way of life. Now, biologists trying to study jaguars in the wild are handicapped because they have become so rare. Most of their information comes from zoos, where jaguars have been bred successfully.
It appears that male and female and female jaguars meet in the wild only to mate. The male leaves as soon as mating is over, and the female brings up the young on her own. She produces between one and four cubs, which are blind at birth and weigh only 700-900 grams each. All-black jaguars are not uncommon. These cubs would have had a spotted father and a black mother.
Two weeks later, the cubs will open their eyes. During the following weeks they begin to explore the world outside of their mothers den until – at about six months old – they begin to accompany her on hunting trips.
The cubs will live and hunt with their mother for the first two years of their life, before leaving to find a territory of their own in which to hunt. A jaguar is sexually mature at three years old, but males do not breed until a year later.
Dolphins are arguably the best known and loved of all the marine mammals. However, many aspects of the dolphins way of life still remain a mystery. Be that as it may, dolphins have been the subject of scientific research for decades and so at least there are some areas of dolphin behaviour that we do know of.
So, just what is a dolphin?
Dolphins are very sociable animals and live in groups comprised of a single sex, or a mixed group of males, females and their young calves. They also help each other when hunting, giving birth or when sick, so their friendly and co-operative behaviour is actually a vital part of social bonding and species survival. They also spend a large part of the day in play including the adult males!
Dolphins use whistles and clicks to communicate with each other. It is not yet known how complicated this language is, but they undoubtedly recognise and respond to one another.
Breeding
Dolphins usually mate in the spring and the summer, and the females give birth underwater to a single calf 10 to 12 months later.
Two, and sometimes even more, dolphin 'midwives' surround the mother to help with the delivery and also to protect her and the new born calf from attack by sharks attracted to blood shed during the birthing process. Sometimes, the midwives will gently tug at the baby's tail as it emerges while whistling encouragement to both mother and youngster. Then, as a group, they move together in order to help guide the new born to the surface so that it can take its first, vital breath of air. However, female dolphins are still quite capable of giving birth without the assistance of others.
Once the calf is born, it will suckle 3.4 liters of milk every day for 9 months or less. Baby dolphins do not have lips and since they are unable to suckle the nipple, they hit it with their rostrum (beak) until the milk is ejected. The dolphin mother will nurse her calf for at least 16 months, so she generally comes into breeding condition once every two to three years. Each time she does breed it is likely to be with a different male.
This kind of social help also extends to injured dolphins too. An injured dolphins cries of distress will summon instant aid from other dolphins in the vacinity. They will then try and carry or support the injured dolphin in the water so that it is able to reach the surface and breathe.
What do dolphins eat?
The worlds dolphin populations are made up from almost forty species varying in size from 1.2 m and 40 for the Maui's dolphin, and up to 9.5 m and 10 tonnes for the killer whale. They are found worldwide, mostly in the shallower seas of the continental shelf. So clearly, with this much variation within the dolphin family, you can expect the same variation in each species diet.
So, while some dolphins eat fishes like herring, cod or mackerel, others species will prefer to eat squids.
Of course, the largest of all the dolphin species - the killer whales - will also eat marine mammals like seals or sea lions and sometime even turtles.
Usually, the amount of fish that they eat depends on the kind of fish that they hunt. While mackerel or herring will contain a lot of fatty oils in their bodies, squid will not have so much, therefore, to get enough energy required for their activities, dolphins will have to eat a lot more squid than mackerel.
On average, a dolphin with a weigh of 200 to 250 Kg will eat between 10 and 25 Kg of fish every day.
How do dolphins catch their food
As you can expect, various methods of feeding exist among and within species, some apparently exclusive to a single population. Fish and squid are the main food, but the false killer whale and the orca (the true killer whale) also feed on other marine mammals like seals. They have been known to eat penguins and even sea turtles!
One common feeding method is herding, where a pod squeezes a school of fish into a small volume, known as a bait ball. Individual members then take turns ploughing through the ball, feeding on the stunned fish.
Corralling is another method where dolphins chase fish into shallow water to more easily catch them. In South Carolina, the Atlantic bottlenose dolphin takes this further with "strand feeding", driving prey onto mud banks for easy access.
In some places, orcas come to the beach to capture sea lions. Some species also hit fish with their tails, stunning them and sometimes knocking them out of the water.
Dolphin communication
Dolphins are capable of making a broad range of sounds using nasal airsacs located just below the blowhole. There are roughly three categories of sounds can be identified: frequency modulated whistles, burst-pulsed sounds and clicks. Dolphins communicate with whistle-like sounds produced by vibrating specialised connective tissue - similar to how human vocal cords function, and through burst-pulsed sounds. However, the nature and extent of that ability is not known.
The clicks are directional and are for echolocation, often occurring in a short series called a click train. The click rate increases when approaching an object of interest. Amazingly, dolphin echolocation clicks are amongst the loudest sounds made by marine animals!
In 2011 researchers in the United States and Great Britain have been using a CymaScope to find out more - a CymaScope is an instrument which produces visible patterns from sound. They have found that part of dolphin communication consists of receiving and transmitting sound pictures. It is almost certain that to this ability is shared by the entire dolphin family.
Can humans communicate with dolphins?
Scientists such as John Lilly have been working with captive bottlenose dolphins since the early 1960s. Even then, it was thought that it would be only a few years before there was a communication breakthrough.
Impressed with their large brains, Lilly performed many audio experiments in order to attempted to show that dolphins were communicating with each other. In an effort to enhance human dolphin communication, he began to use computers to translate human words into dolphin whistles and to send messages back. Unfortunately,much of his experimental work has never been published.
In one Lilly experiment, a woman lived in a pool with a bottlenose dolphin named Peter as her only companion for several months. Sleeping in a bed above the pool, she was ever on call. Communication attempts were often transing sessions, where the woman attempted to teach language to the dolphin. Peter was reportedly a demanding 'roommate', and the woman eventually withdrew from the project. While a basic communication did develop, reportedly similar to that between a dog and a human, deeper exchanges - of dolphin whistles or human words - did not occur.
Lilly's work ended in the 1980s. Since then, researchers led by Louis M. Herman have developed a new approach to communication studies with captive bottlenose dolphins at the University of Hawaii. Their goals have been to discover how dolphins process information - both through sight and sound, how they learn, and how they communicate. Herman's research has verified earlier findings that dolphins have good memories and can mimic a wide variety of sounds. Able to store new information, they can also quickly update old information.
In one experiment, Herman played up to eight different short sounds on an underwater speaker in the dolphin's tank. Then another sound was played, sometimes one of the previous eight, sometimes an entirely new sound. The dolphin had to decide whether it had heard the sound before. About 70 percent of the time, the dolphin responded correctly. If the list was shortened, however, to one or two sounds, the results were 90 percent correct. Like humans given such tests, the dolphins found the recent items easiest to remember.
The dolphin's most impressive accomplishment is its ability to understand sentences expressed in either an artificial acoustic or a visual language. In the experiments, the "words" of the language are sounds generated by a computer and broadcast via an underwater speaker. First the dolphin learns words such as fetch, ball and hoop. The words refer to (1) objects in the tank; (2) actions that might be taken in connection with the objects; and (3) modifiers of place or location. In "sentences" of two or more words, the dolphin is then told to do something. The level of understanding is measured by the accuracy and reliability with which the dolphin carries out the instruction.
Dolphins perform very well on such tests. To more than 600 two-word sentence instructions, the dolphins gave correct responses about 80 percent of the time. They also understood "new" instructions almost as well as familiar ones, with only a slight advantage to the familiar. New instructions consisted of fresh combinations of words that either obeyed the language rules or, in a few cases, were logical extensions of existing rules.
Gradually, the dolphins seemed to master sentence form and use. They were taught to respond to sentences up to five words long. Then visual symbols or gestures, as well as auditory signals, were tried. Comprehension for a dolphin trained with visuals was the same as that for a dolphin trained with sound.
These and other experiments clearly show that dolphins can learn rules and understand certain abstract concepts. They can also work with both auditory and visual symbols. Compared to apes which have been taught to use America sign language - an exclusively visual medium for communication - the dolphins have more range. The apes, on the other hand, learn more quickly in tests involving symbols. Of course, all of these are laboratory feats and prove nothing about life in the wild - for dolphins or apes.
In the future, trained dolphins may be able to grasp more complex human-taught vocabularies. But this does not necessarily mean that dolphins have their own language. No-one yet knows where this research will lead, but many scientists feel that we have only glimpst what really goes on inside the mind of a wild dolphin.
Can dolphins kill sharks?
Dolphins and many shark species are similar in shape and size, and inhabit the same regions and depths of the ocean. Sharks have a reputation for being fierce predators. hardly surprising when they are armed with rows of sharp serrated teeth that can easily bite through flesh and bone. Unlike dolphins, sharks have a very tough, sandpaper-like skin that is not easily punctured.
Dolphins, on the other hand, are seen as intelligent, playful creatures. They only have a single row of peg-like teeth which is mainly used for catching smaller fish. Their skin is soft, flexible and can be cut easily.
So at face value, it would seem that sharks would have the edge over a dolphin in a face to face fight - but all is not as it seems!
Since dolphins normally travel together in a group - known as a pod, if one of them is threatened by a shark, the other members of the group will join in to defend the dolphin that is in danger.
The dolphin's main weapon is their snout, otherwise known as their beak. It is made of very strong and thick bone, and has a hard, rounded end.
If the pod decides to defend against a likely shark attack, the dolphins will circle the shark very rapidly from different directions. This causes the shark to become confused and is then unable to choose a specific dolphin to chase. When a dolphin becomes suitably positioned below a shark - usually at a distance of several meters, the dolphin will make a sudden rush at the shark's softer underbelly ramming it with his snout. This has the effect is like an extremely powerful punch. The shark can be seriously injured with a single blow, and they are often stunned or knocked unconscious. The dolphins will sometimes repeatedly ram a shark that has been very aggressive, and are quite capable of killing a large, dangerous shark.
However, attacking dangerous sharks clearly has an element of serious risk and so dolphins are often unwilling to attack the 'bigger boys' such as white sharks, tiger sharks, mako sharks and bull sharks, unless of course they have good reason to ie. protecting pregnant females, calves or injured individuals.
However, if a pod has no good reason to stay and fight then they will, more often than not, swim away.
Gorillas are the largest species of primates alive today. They are ground-dwelling, predominantly herbivorous, and although they are frequently portrayed as aggressive, dangerous killers, they are in reality shy, peaceful vegetarians. Furthermore, because of massive loss of habitat, these majestic primates are now at huge risk of extinction!
Gorillas are divided into two species and then further still into four or five subspecies. The DNA of gorillas is incredibly similar to that of humans, between 95 and 99%! In fact they are our closest living relatives next to chimpanzees.
Gorilla Habitat
The Gorillas natural habitat covers the tropical and subtropical forests of Africa. Although their range covers only a small percentage of Africa, gorillas cover a wide range of elevations. The mountain gorilla inhabits the Albertine Rift montane cloud forests of the Virunga Volcanoes, ranging in altitude from 7,200–14,100 ft. Lowland Gorillas live in dense forests and lowland swamps and marshes as low as sea level, with western lowland gorillas living in Central West African countries and eastern lowland gorillas living in the Democratic Republic of the Congo near its border with Rwanda.
Gorilla Behaviour
Gorillas live in groups called troops. Each troops will tend to be made of one adult male or silverback, multiple adult females, and their offspring. However, multi-male troops also exist.
Silverbacks are typically more than 12 years of age and named for the distinctive patch of silver hair on his back, which comes with maturity. A silverback gorilla has large canine teeth that also come with maturity.
Both males and females tend to emigrate from their natal groups. Dispersal from natal troops is more common in females than males for mountain gorillas. Female mountain gorillas and western lowland gorillas also commonly transfer to a second new group.
Mature males tend to also leave their groups and establish their own troops by attracting emigrating females. However, male mountain gorillas sometimes stay in their natal troop and become subordinate to the silverback. They may gain the opportunity to mate with new females or become dominant if the silverback dies. This behaviour has not been observed in eastern lowland gorillas.
In a single male group, when the silverback dies, the females and their offspring disperse and find a new troop. Without a silverback to protect them, the infants will likely fall victim to infanticide, and seaching out and joining a new group is likely to be a tactic against this. However, while gorilla troops usually disband after the silverback dies, female eastern lowlands gorillas and their offspring have been recorded staying together until a new silverback transfers into the group. This likely serves to decrease chance of being attacked by leopards. Although very rare, all male troops have also been recorded.
Silverback Gorillas
The silverback is the center of the troop's attention, making all the decisions, mediating conflicts, determining the movements of the group, leading the others to feeding sites and taking responsibility for the safety and well-being of the troop.
Younger males subordinate to the silverback, known as blackbacks, may serve as backup protection. Blackbacks are males between 8 and 12 years of age and lack the silver back hair. The bond a silverback has with his females forms the core of gorilla social life.
Bonds between them are maintained by grooming and close proximity. Having strong relationships with males is important for females as males give them mating opportunities and protection from predators and infanticide from outside males. However aggressive behaviours between males and females are common although they rarely lead to serious injury.
Relationships between females may vary. Maternally related females in a troop associate closely and tend to have friendly interactions. Otherwise, females usually have little friendly interactions and commonly act aggressive towards each other. Aggressive interactions between females tend to be centred around social access to males with males intervening in fights between females. Male gorillas have weak social bonds, particularly in multi-male groups with apparent dominance hierarchies and strong competition for mates. However, males in all-male groups tend to have friendly interactions and socialize through play, grooming and close proximity, and occasionally they even engage in homosexual interactions.
Gorilla Nests
Gorillas construct nests for daytime and night use. Day nests tend to be simple aggregations of branches and leaves on the ground while night nests are more elaborate constructions in trees. The nests may be 2 to 5 feet in diameter and are constructed by individuals. The young nest with the mother but construct nests after three years of age, initially close to that of their mother. Gorilla nests are distributed arbitrarily and use of tree species for site and construction appears to be opportunistic. Nest building by great apes is now considered to be not just animal architecture but as an important instance of tool use.
How do Gorillas Communicate?
There are now twenty-five distinct vocalizations recognized now through extensive scientific research, many of which are used primarily for group communication within dense vegetation. These sounds classified as grunts and barks are heard most frequently while travelling.
They are often used to indicate the whereabouts of individual group members. They may also be used during social interactions when discipline is required. Screams and roars signal alarm or warning, and are produced most often by silver-backs.
Deep, rumbling belches suggest contentment and are heard frequently during feeding and resting periods. They are the most common form of intra-group communication. Severe aggression is rare in stable groups, but when two mountain gorilla groups meet, the two silver-backs can sometimes engage in a fight to the death, using their canines to cause deep, gaping injuries. The entire sequence has nine steps:
1. Progressively quickening hooting. 2. symbolic feeding. 3. Standing upright. 4. Throwing vegetation. 5. Chest-beating with cupped hands. 6. A single leg kick. 7. Sideways running, two-legged to four-legged. 8. Slapping and tearing vegetation. 9. thumping the ground with palms to end display.
In September 2005, a two and a half year old gorilla in the Republic of Congo was discovered using rocks to smash open palm nuts inside a game sanctuary. While this was the first such observation for a gorilla, over 40 years previously chimpanzees had been seen using tools in the wild, famously 'fishing' for termites.
Great apes are endowed with a semi-precision grip, and certainly have been able to use both simple tools and even weapons, by improvising a club from a convenient fallen branch.
The grey wolf - otherwise known as the timber wolf, white wolf or 'common' wolf - lives in a variety of habitats, from the Arctic tundra and open steppes of Russia, to the mountainous regions and forests of the northern hemisphere. It has a highly organised social structure which enables it to enjoy the maximum cooperation when hunting, communicating, and defending its territory.
The grey wolf lives in packs of between five and ten animals. Each pack contains a family unit,consisting of a dominant male and female, and the offspring from several years. The hierarchy that exists within each pack is maintained by dominant or submissive body posturing, as well as other behavioural patterns such as the communal care of the young.
The size of the pack's territory depends on the availability of prey, but usually covers several hundred square kilometres. The grey wolf is fiercely territorial. It scent marks boundaries and makes its presence known by howling to other members of the pack. Calls may be answered by rival wolf packs.
What do wolves eat?
The grey wolf is a big-game hunter from the dog family, hunting mostly hoofed animals. A single wolf is capable of catching and killing a deer unaided, but when hunting as a pack, it will prey on larger animals such as the moose.
Relying chiefly on its hearing and sense of smell to detect prey, the wolf will follow its target all day and night if necessary. It is not particularly fast - the wolf has a top speed of about 45 km per hour, but it does have remarkable powers of endurance which is the key to its hunting success. After a kill, each wolf - starting with high ranking individuals - will eat as much meat as it can. This can sometime be as much as one fifth of its entire body weight! What cannot be consumed is left for scavengers, even though the wolf may have to wait another three or four days before it catches its next meal.
Each member of the pack hunts, except for those too young to join in. These remain at home and wait for food to be brought to them.
Where does the grey wolf live?
The grey wolf has always been feared by man and has been persecuted more than any other animal, but its cunning, intelligence, and flexibility have saved it from extinction.
Once widespread throughout North America, Canada, Europe and the Far East, the grey wolf is sadly now only found in large numbers in specific parts of Russia, North America and Eastern Europe. Small numbers also occur in the Abruzzi mountains in Italy.
The main reason for the wolf's continuing decline has been the dramatic reduction of its natural prey. This has largely been replaced by farm stock which is protected by the use of poisons, traps and even guns. It is still shot in Europe despite legal protection.
The final fate of the wolf will depend on whether mankind can allow the animal the co-exist alongside him.
Breeding
The grey wolf becomes sexually mature at about two years of age. Once a wolf has found a mate the pair will usually stay together for life. The mating season begins at the end of winter and often causes tension within the pack.
Subordinate males and females compete for a higher place in the hierarchy of the pack, for it only the most dominant wolves that get the opportunity to mate. Unfortunately, the majority of wolves do not get to breed. Instead, they get to choose to help their siblings rear pups by hunting prey for them.
Once they have paired, the dominant male and female will mate once or twice a day over a period of about 14 days.
The female wolf will give birth after about nine weeks to between 3 and 10 cubs. The birth occurs in an underground den that she would have excavated herself. However, she will sometime enlarge the disused den of another animal.
The young are born helpless and their eyes are closed. The mother will feed the cubs for 6 to 8 weeks, and - if she has to leave them - the father or another babysitter will guard them.
Gradually, the cubs will learn to eat meat brought to them in the den by adult wolves. The adult will sometimes carry the meat in its mouth, but over long distances it will swallow it, only to regurgitate it later at the den.
