The Trials of Life

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''The Trials of Life: A Natural History of Behaviour'' is a

BBC #REDIRECT BBC #REDIRECT BBC Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...

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nature documentary A nature documentary or wildlife documentary is a genre of documentary film or series about animals, plants, or other non-human living creatures, usually concentrating on video taken in their natural habitat but also often including footage of t ...

series written and presented by David Attenborough, first transmitted in the United Kingdom from 3 October 1990. A study in animal behaviour, it was the third in a trilogy of major series (beginning with '' Life on Earth'') that took a broad overview of nature, rather than the more specialised surveys of Attenborough's later productions. Each of the twelve 50-minute episodes features a different aspect of the journey through life, from birth to adulthood and continuation of the species through reproduction. The series was produced in conjunction with the

Australian Broadcasting Corporation The Australian Broadcasting Corporation (ABC) is the national broadcaster of Australia. It is principally funded by direct grants from the Australian Government and is administered by a government-appointed board. The ABC is a publicly-own ...

and

Turner Broadcasting System Turner Broadcasting System, Inc. (alternatively known as Turner Entertainment Networks from 2019 until 2022) was an American television and media conglomerate. Founded by Ted Turner and based in Atlanta, Georgia, it merged with Time Warner (lat ...

Inc. The executive producer was Peter Jones and the music was composed by

George Fenton George Richard Ian Howe (born 19 October 1949), known professionally as George Fenton, is an English composer. Best known for his work writing film scores and music for television, he has received five Academy Award nominations, several Ivor No ...

. Part of David Attenborough's 'Life' series, it was preceded by ''

The Living Planet ''The Living Planet: A Portrait of the Earth'' is a BBC nature documentary series written and presented by David Attenborough, first transmitted in the UK from 19 January 1984. The sequel to his pioneering '' Life on Earth'', it is a study of t ...

'' (1984) and followed by ''

Life in the Freezer ''Life in the Freezer'' is a BBC nature documentary series written and presented by David Attenborough, first transmitted in the United Kingdom from 18 November 1993. A study of the seasonal cycle of Antarctica, it was the first of Attenborou ...

'' (1993).

Background

The series took over three-and-a-half years to film, during which time Attenborough travelled almost a quarter of a million miles. The production team sought to further push the boundaries of natural history film-making, following on from the advances made in ''The Living Planet'', and were provided with several new challenges. The sequence of chimpanzees hunting

colobus monkey Black-and-white colobuses (or colobi) are Old World monkeys of the genus ''Colobus'', native to Africa. They are closely related to the red colobus monkeys of genus '' Piliocolobus''. There are five species of this monkey, and at least eight subs ...

s was only possible through the efforts of Hedwige and Christophe Boesch, who had spent five years studying the apes in the Ivory Coast forests of

West Africa West Africa or Western Africa is the westernmost region of Africa. The United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, M ...

. Meanwhile, a bivouac of

army ant The name army ant (or legionary ant or ''marabunta'') is applied to over 200 ant species in different lineages. Because of their aggressive predatory foraging groups, known as "raids", a huge number of ants forage simultaneously over a limi ...

s in

Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Co ...

was able to be filmed internally with the aid of a medical endoscope. Furthermore, a new type of camera lens enabled tree ants to be filmed in enlarged close-up just in front of Attenborough – with both subjects in sharp focus. This gave the illusion that the insects were much larger than their actual size. Filming critical moments in the life of a herd of

elephant Elephants are the largest existing land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantidae ...

s necessitated the expertise of

Cynthia Moss Cynthia Jane Moss (born July 24, 1940) is an American ethologist and conservationist, wildlife researcher, and writer. Her studies have concentrated on the demography, behavior, social organization, and population dynamics of the African elephant ...

, who had devoted 25 years to researching the animals in

Kenya ) , national_anthem = " Ee Mungu Nguvu Yetu"() , image_map = , map_caption = , image_map2 = , capital = Nairobi , coordinates = , largest_city = Nairobi ...

. She was able to advise the production team on the right moments to film specific events. The camera team had only one chance to film a 60,000-strong flock of

wader 245px, A flock of Dunlins and Red knots">Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflat ...

s flying over David Attenborough's head in

Norfolk Norfolk () is a ceremonial and non-metropolitan county in East Anglia in England. It borders Lincolnshire to the north-west, Cambridgeshire to the west and south-west, and Suffolk to the south. Its northern and eastern boundaries are the No ...

, and the RSPB was enlisted to predict their flight path. By contrast, the

Florida scrub jay The Florida scrub jay (''Aphelocoma coerulescens'') is one of the species of scrub jay native to North America. It is the only species of bird endemic to the U.S. state of Florida and one of only 15 species endemic to the continental United State ...

s couldn't have been more co-operative: since the particular group being filmed had been studied closely and were used to humans, a bird could land on Attenborough's hand right on cue. The inside of a

termite Termites are small insects that live in colonies and have distinct castes (eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blatto ...

mound proved especially challenging for Attenborough: it was so cramped that he could only face in one direction. He therefore had to slowly crawl backwards out of shot when performing re-takes. Behaviour seen for the first time included the sequence that was eventually selected to illustrate the series' DVD cover: that of a

killer whale The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus ''Orcinus'' and is recognizable by its black-and-white ...

pouncing on a colony of

sea lion Sea lions are pinnipeds characterized by external ear flaps, long foreflippers, the ability to walk on all fours, short and thick hair, and a big chest and belly. Together with the fur seals, they make up the family Otariidae, eared seals. ...

s on a

Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and g ...

n beach and 'playing' with its young prey before consuming it. This meant some risks being taken by the cameramen, as they placed themselves in the water just feet away from the creatures in order to obtain close-ups of an attack run.

Episodes

1. "Arriving"

Broadcast 3 October 1990, the first episode examines the various methods by which creatures come into the world. Attenborough's opening statement alludes to the annual spawning of the

Christmas Island red crab The Christmas Island red crab (''Gecarcoidea natalis'') is a species of land crab that is endemic to Christmas Island and Cocos (Keeling) Islands in the Indian Ocean. Although restricted to a relatively small area, an estimated 43.7 million a ...

, of which there are estimated to be some 120 million. The exercise is all the more hazardous since the species is a land crab, and the eggs have to be deposited in the sea – where the most ancient animals on the planet still live and breed. One of the most prolific aquatic egg producers is the

giant clam The giant clams are the members of the clam genus '' Tridacna'' that are the largest living bivalve mollusks. There are actually several species of "giant clams" in the genus '' Tridacna'', which are often misidentified for ''Tridacna gigas'', ...

, but some land animals also lay vast quantities, and the

mantis Mantises are an order (Mantodea) of insects that contains over 2,400 species in about 460 genera in 33 families. The largest family is the Mantidae ("mantids"). Mantises are distributed worldwide in temperate and tropical habitats. They ha ...

is one example. In the Western United States, Attenborough observes a

wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. ...

that digs a burrow, conceals it, and stocks it with fresh caterpillars for her emerging young. The grubs of another start life inside caterpillars, and eat the unsuspecting hosts. The problems of larger animals are illustrated by

snow geese The snow goose (''Anser caerulescens'') is a species of goose native to North America. Both white and dark morphs exist, the latter often known as blue goose. Its name derives from the typically white plumage. The species was previously placed ...

in the

Arctic The Arctic ( or ) is a polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenland), Finland, Iceland, N ...

, which have to defend their eggs from

Arctic fox The Arctic fox (''Vulpes lagopus''), also known as the white fox, polar fox, or snow fox, is a small fox native to the Arctic regions of the Northern Hemisphere and common throughout the Arctic tundra biome. It is well adapted to living in ...

es. The process of embryonic growth inside the egg, from laying to hatching, is shown in detail. The

malleefowl The malleefowl (''Leipoa ocellata'') is a stocky ground-dwelling Australian bird about the size of a domestic chicken (to which it is distantly related). It is notable for the large nesting mounds constructed by the males and lack of parental ca ...

warms its eggs with rotting leaves, and Attenborough demonstrates the care with which it regulates them by adding sand to its mound – to have it kicked back in his (Attenborough's) face. The

sea louse Sea lice (singular: sea louse) are copepods (small crustaceans) of the family Caligidae within the order Siphonostomatoida. They are marine ectoparasites (external parasites) that feed on the mucus, epidermal tissue, and blood of host fish. The ...

is a

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

that commits suicide: its grubs consume so much of the mother's energies that she dies after birth. Mammals shown giving birth to fully formed young include

wildebeest Wildebeest ( , , ), also called gnu ( or ), are antelopes of the genus ''Connochaetes'' and native to Eastern and Southern Africa. They belong to the family Bovidae, which includes true antelopes, cattle, goats, sheep, and other even-to ...

, antelope,

s and chinchillas.

2. "Growing Up"

Broadcast 10 October 1990, this programme describes the ways that various species care for their young. Attenborough defines childhood as achieving two tasks: growing and surviving. He highlights the

elephant seal Elephant seals are very large, oceangoing earless seals in the genus ''Mirounga''. Both species, the northern elephant seal (''M. angustirostris'') and the southern elephant seal (''M. leonina''), were hunted to the brink of extinction for oi ...

as an animal that experiences a compressed childhood, being abandoned after three weeks and left for up to another eight alone, while it becomes large enough to be able to swim. For

tern Terns are seabirds in the family Laridae that have a worldwide distribution and are normally found near the sea, rivers, or wetlands. Terns are treated as a subgroup of the family Laridae which includes gulls and skimmers and consists of e ...

s, there is safety in numbers as the dense population works together to drive out marauding

gull Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century ...

s. The snow geese in the Russian Arctic show intense devotion as they escort their goslings by foot to the coast some 50 kilometres away.

Scorpion Scorpions are predatory arachnids of the order Scorpiones. They have eight legs, and are easily recognized by a pair of grasping pincers and a narrow, segmented tail, often carried in a characteristic forward curve over the back and always en ...

s carry their young on their backs, while a

shrew Shrews (family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to differ ...

will leave hers under a stone while she goes to feed. The

eider duck Eiders () are large seaducks in the genus ''Somateria''. The three extant species all breed in the cooler latitudes of the Northern Hemisphere. The down feathers of eider ducks, and some other ducks and geese, are used to fill pillows and quil ...

is one creature that shares responsibility for its offspring: females regularly supervise the ducklings of others in a group. The mara is another that uses a crèche system, as does the

bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most ...

, whose nurseries can be up to a million strong. The Florida scrub jay has a complex system of raising young known as

cooperative breeding Cooperative breeding is a social system characterized by alloparental care: offspring receive care not only from their parents, but also from additional group members, often called helpers. Cooperative breeding encompasses a wide variety of group s ...

, where young stay on as helpers at the nest of their parents. Such behaviour is exhibited on a larger scale by elephants, where all females take an interest in raising a single calf. A chimpanzee's childhood is socially complicated, as an individual must learn how to behave towards others, as well as master the use of tools. Albatrosses must be accomplished fliers as soon as possible – chicks are shown being hunted by

tiger shark The tiger shark (''Galeocerdo cuvier'') is a species of requiem shark and the last extant member of the family Galeocerdonidae. It is a large macropredator, capable of attaining a length over . Populations are found in many tropical and tempera ...

3. "Finding Food"

Broadcast 17 October 1990, the next instalment is devoted to the ways in which animals gather their sustenance. Attenborough begins in the

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

n rainforest, where the proliferation of animal and plant life does not necessarily make it easy to find food. Some leaves are poisonous, and so those that eat them have to be careful. Other plants use food (or nectar) as a bribe to get their pollen transported, and several species of hummingbird have developed exclusive relationships with certain of them. Fruit is also on offer, again as a means of reproduction, and creatures such as

squirrel monkey Squirrel monkeys are New World monkeys of the genus ''Saimiri''. ''Saimiri'' is the only genus in the subfamily Saimirinae. The name of the genus is of Tupi origin (''sai-mirím'' or ''çai-mbirín'', with ''sai'' meaning 'monkey' and ''mirím'' ...

s eat little else. Meanwhile,

parrot Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoide ...

s and macaws take

kaolin Kaolinite ( ) is a clay mineral, with the chemical composition Al2 Si2 O5( OH)4. It is an important industrial mineral. It is a layered silicate mineral, with one tetrahedral sheet of silica () linked through oxygen atoms to one octahedral ...

as an antidote to their diet of toxic seeds. Attenborough witnesses a 60,000 strong flock of

knot A knot is an intentional complication in cordage which may be practical or decorative, or both. Practical knots are classified by function, including hitches, bends, loop knots, and splices: a ''hitch'' fastens a rope to another object; a ' ...

and

dunlin The dunlin (''Calidris alpina'') is a small wader, formerly sometimes separated with the other "stints" in the genus ''Erolia''. The English name is a dialect form of "dunling", first recorded in 1531–1532. It derives from ''dun'', "dull brown ...

suddenly take advantage of a low tide to feed on tiny mud-dwelling molluscs.

Barracuda A barracuda, or cuda for short, is a large, predatory, ray-finned fish known for its fearsome appearance and ferocious behaviour. The barracuda is a saltwater fish of the genus ''Sphyraena'', the only genus in the family Sphyraenidae, which was ...

hunt small fish, and drive shoals of them into bays to be eaten by pelicans, which are besieged by gulls that attempt to steal their catches. One species of gecko is able to differentiate between worker

s and the more dangerous soldiers. The web of the orb spider is hailed as one of the most elegant food catching devices, and the methods of two others,

nephila ''Nephila'' is a genus of araneomorph spiders noted for the impressive webs they weave. ''Nephila'' consists of numerous species found in warmer regions around the world. They are commonly called golden silk orb-weavers, golden orb-weavers, gian ...

and its

kleptoparasite Kleptoparasitism (etymologically, parasitism by theft) is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, which can mean when foo ...

visitor,

argyrodes ''Argyrodes'', also called dewdrop spiders, is a genus of comb-footed spiders that was first described by Eugène Louis Simon in 1864. They occur worldwide, and are best known for their kleptoparasitism. They can spin their own webs, but tend to ...

, are explored in detail. Finally,

tropicbirds Tropicbirds are a family, Phaethontidae, of tropical pelagic seabirds. They are the sole living representatives of the order Phaethontiformes. For many years they were considered part of the Pelecaniformes, but genetics indicates they are most c ...

, their

crop A crop is a plant that can be grown and harvested extensively for profit or subsistence. When the plants of the same kind are cultivated at one place on a large scale, it is called a crop. Most crops are cultivated in agriculture or hydropon ...

s full with food en route back to their nests, are ambushed in mid-air by a group of

frigatebird Frigatebirds are a family of seabirds called Fregatidae which are found across all tropical and subtropical oceans. The five extant species are classified in a single genus, ''Fregata''. All have predominantly black plumage, long, deeply forked ...

s, whose aim is to make them surrender their cargo.

4. "Hunting and Escaping"

Broadcast 24 October 1990, this episode looks at those that hunt other creatures and ways of avoiding capture. Attenborough is attacked by a pair of

skua The skuas are a group of predatory seabirds with seven species forming the genus ''Stercorarius'', the only genus in the family Stercorariidae. The three smaller skuas, the long-tailed skua, the Arctic skua, and the pomarine skua are called ...

s as he approaches their nest, which demonstrates this particular bird's aggressive behaviour, both when taking food and defending its young. Off the shores of Patagonia, the same group of

s returns each year to ambush

pups, which stray out of the safer shallow waters. Having grabbed their prey, they take it back out to sea and '

play Play most commonly refers to: * Play (activity), an activity done for enjoyment * Play (theatre), a work of drama Play may refer also to: Computers and technology * Google Play, a digital content service * Play Framework, a Java framework * P ...

' with it for some time before killing it. Poison can be used both as a weapon and a deterrent, such as by the

viper The Viperidae (vipers) are a family of snakes found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, and various other isolated islands. They are venomous and have long (relative to non-vipers), hinged fangs tha ...

and tomato frog respectively. Some animals advertise their defensive measures in advance, in case deployment occurs too late. Among them are the skunk, which discharges an appalling smell, and some

salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...

s that display their toxicity by remaining stationary, with their warning markings visible. Several species of stick insect and their elaborate camouflage are shown. However, none of these methods of protection pose problems to

s, which can subdue any of their prey, simply by virtue of their size and vast numbers. The

Harris hawk The Harris's hawk (''Parabuteo unicinctus''), formerly known as the bay-winged hawk, dusky hawk, and sometimes a wolf hawk, and known in Latin America as peuco, is a medium-large bird of prey that breeds from the southwestern United States south ...

is unusual, since it hunts in teams, and a group of six are shown practising their skill in the desert of

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ke ...

. The final sequence depicts a troop of chimpanzees displaying strategy and co-ordination as it successfully pursues colobus monkeys through a forest in the Ivory Coast.

5. "Finding the Way"

Broadcast 31 October 1990, this programme explores forms of navigation. Attenborough starts in

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

at dusk, by describing some of the species that don't rely on

sight Visual perception is the ability to interpret the surrounding environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the visible spectrum reflecte ...

. The spotted hyena uses its acute sense of smell to guide it while it hunts nocturnally, while

galago Galagos , also known as bush babies, or ''nagapies'' (meaning "night monkeys" in Afrikaans), are small nocturnal primates native to continental, sub-Sahara Africa, and make up the family Galagidae (also sometimes called Galagonidae). They are ...

s urinate on their hands so they can completely mark their movements. Some animals use echolocation and these include

swiftlet Swiftlets are birds contained within the four genus, genera ''Aerodramus'', ''Hydrochous'', ''Schoutedenapus'' and ''Collocalia''. They form the Collocaliini tribe (biology), tribe within the Swift (bird), swift family Apodidae. The group contain ...

s, bats and

river dolphin River dolphins are a polyphyletic group of fully aquatic mammals that reside exclusively in freshwater or brackish water. They are an informal grouping of dolphins, which itself is a paraphyletic group within the infraorder Cetacea. Extant riv ...

s. By contrast,

electric eel The electric eels are a genus, ''Electrophorus'', of neotropical freshwater fish from South America in the family Gymnotidae. They are known for their ability to stun their prey by generating electricity, delivering shocks at up to 860 volt ...

s use fields of electricity to sense their environment. During the hours of daylight, other methods are employed: the rufous elephant shrew, with its carefully cleared network of pathways, has a sharp mental picture of its habitat – even knowing the various shortcuts with which to evade capture. Attenborough visits the Sahara to illustrate a species that makes the longest overland journey of any insect: cataglyphis, an ant that uses the

sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

's position to enable it to return to its nest in a straight line. Lobsters in

the Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to 88% of the ar ...

are shown marching in columns to escape stormy waters. In its search for perpetual daylight in which to fish, the Arctic tern makes a 19,000-kilometre journey from one end of the

earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

to the other. The albatross is highlighted as one of the most skilled navigators: it can travel up to 1300 kilometres over sea in search of food for its chicks, and still find its way back to the nest. Finally, Attenborough stands on a waterfall in Ireland to tell of the three-year, 10,000-kilometre journey made by elvers.

6. "Home Making"

Broadcast 7 November 1990, this instalment deals with how animals construct their shelters from the elements and predators. Burrows and holes can provide considerable refuge, and Attenborough inspects the home of the American prairie dog, an elaborate construction that has its own air conditioning system.

Silk Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the ...

is such a valuable commodity that those that can't make it steal it instead. The hermit hummingbird uses it to attach its nest to the underside of a leaf, while the Indian tailorbird stitches two leaves together. However, the expert in complex nest-building is the weaverbird which makes its abode from over 1,000 strips of grass that are perfectly interwoven – and dismantling it if it fails to attract a mate. The beaver is responsible for one of the biggest animal dwellings: its wooden lodge that rises from the river bed stays in place from one generation to the next, and so requires constant maintenance. Some stingless bees use their

wax Waxes are a diverse class of organic compounds that are lipophilic, malleable solids near ambient temperatures. They include higher alkanes and lipids, typically with melting points above about 40 °C (104 °F), melting to giv ...

and the

resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on n ...

of tree bark to create labyrinthine structures containing various compartments. Mud is also used by several creatures, such as the

potter wasp Potter wasps (or mason wasps), the Eumeninae, are a cosmopolitan wasp group presently treated as a subfamily of Vespidae, but sometimes recognized in the past as a separate family, Eumenidae. Recognition Most eumenine species are black or brown, ...

and the cliff swallow. The

s' intricate creations allow for security, heating, air conditioning, self-contained nurseries and gardens, and sanitation systems. Attenborough hails the species as the consummate home maker, and explores a 15-foot colony in West Africa that contains 1.5 million insects: he crawls right inside to examine its method of ventilation.

7. "Living Together"

Broadcast 14 November 1990, this episode focuses on those species that co-operate and depend on (or exploit) others.

Spotted deer The chital or cheetal (''Axis axis''; ), also known as the spotted deer, chital deer, and axis deer, is a deer species native to the Indian subcontinent. It was first described and given a binomial name by German naturalist Johann Christian Po ...

follow langur monkeys as they travel from tree to tree, eating any leaves that get dropped from above. In return, the deer serve as a lookout when the primates are feeding on the ground. Underwater, a

hermit crab Hermit crabs are anomuran decapod crustaceans of the superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit crab, most of which possess an as ...

is shown adding sea anemones to its shell in order to protect itself from attack by an octopus, and a

goby Goby is a common name for many species of small to medium sized ray-finned fish, normally with large heads and tapered bodies, which are found in marine, brackish and freshwater environments. Traditionally most of the species called gobies have b ...

assists a virtually blind shrimp.

Flea Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about long, a ...

s, lice and

mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear e ...

s are

parasites Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

: they share no mutual partnership and instead take advantage of creatures for food or shelter. However, parasites have their predators, and an example are the

finch The true finches are small to medium-sized passerine birds in the family Fringillidae. Finches have stout conical bills adapted for eating seeds and nuts and often have colourful plumage. They occupy a great range of habitats where they are usua ...

es of the

Galápagos Islands The Galápagos Islands (Spanish: , , ) are an archipelago of volcanic islands. They are distributed on each side of the equator in the Pacific Ocean, surrounding the centre of the Western Hemisphere, and are part of the Republic of Ecuador ...

that clear the resident

giant tortoise Giant tortoises are any of several species of various large land tortoises, which include a number of extinct species, as well as two extant species with multiple subspecies formerly common on the islands of the western Indian Ocean and on the ...

s of their

tick Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...

s, and

oxpecker The oxpeckers are two species of bird which make up the genus ''Buphagus'', and family Buphagidae. The oxpeckers were formerly usually treated as a subfamily, Buphaginae, within the starling family, Sturnidae, but molecular phylogenetic studi ...

s, which do the same for giraffes in Africa (and even use its fur to line their nests). Some fish regularly clean others, and

wrasse The wrasses are a family, Labridae, of marine fish, many of which are brightly colored. The family is large and diverse, with over 600 species in 81 genera, which are divided into 9 subgroups or tribes. They are typically small, most of them le ...

and shrimp appear to specialise in this regard, as do

remora The remora (), sometimes called suckerfish, is any of a family (Echeneidae) of ray-finned fish in the order Carangiformes. Depending on species, they grow to long. Their distinctive first dorsal fins take the form of a modified oval, sucker-li ...

, which permanently hang on to their hosts. One parasite that grows inside its host is the fluke, and one is shown gestating inside a

snail A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class G ...

, having previously been unknowingly eaten. Because it needs to transfer to a bird's gut to develop further, it causes the snail to advertise its presence to allow itself to be consumed – thus completing the circle. However, some microscopic creatures inhabit the stomachs of large herbivores in order to break down the cellulose of their diet, thereby aiding their digestion.

8. "Fighting"

Broadcast 21 November 1990, this programme details how fighting – both physical and psychological – is used for food, land or to gain a mate. Territorial conflict is demonstrated by the hummingbird, and Attenborough illustrates its

aggressiveness Aggression is overt or covert, often harmful, social interaction with the intention of inflicting damage or other harm upon another individual; although it can be channeled into creative and practical outlets for some. It may occur either reacti ...

by placing a stuffed specimen nearby, only to have it speared by its opponent's bill. The

midas cichlid ''Amphilophus citrinellus'' is a large cichlid fish endemic to the San Juan River and adjacent watersheds in Costa Rica and Nicaragua. In the aquarium trade ''A. citrinellus'' is often sold under the trade name of Midas cichlid. ''A. citrinellus ...

on the other hand, has no weapons to speak of, and so uses its mouth to hold on for trials of strength. By contrast, the forelegs of a mantis shrimp are powerful enough to crack the shell of another

: therefore disputes or courtship are fraught with danger. Animals that possess lethal food-gathering weapons usually don't use them against one another, as neither side wishes to risk death. For example, one venomous

snake Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more j ...

will aim to floor the other, rather than bite.

Wolves The wolf (''Canis lupus''; : wolves), also known as the gray wolf or grey wolf, is a large canine native to Eurasia and North America. More than thirty subspecies of ''Canis lupus'' have been recognized, and gray wolves, as popularly un ...

and

big cat The term "big cat" is typically used to refer to any of the five living members of the genus ''Panthera'', namely the tiger, lion, jaguar, leopard, and snow leopard. Despite enormous differences in size, various cat species are quite similar ...

s largely use snarls and body posture to convey their threat. There are no holds barred between rival

zebra Zebras (, ) (subgenus ''Hippotigris'') are African equines with distinctive black-and-white striped coats. There are three living species: the Grévy's zebra (''Equus grevyi''), plains zebra (''E. quagga''), and the mountain zebra (''E. zebr ...

s: kicking and biting is employed until a victor emerges, whereas giraffes slam their necks against each other. Normally peaceful

mountain gorilla The mountain gorilla (''Gorilla beringei beringei'') is one of the two subspecies of the eastern gorilla. It is listed as endangered by the IUCN as of 2018. There are two populations: One is found in the Virunga volcanic mountains of Centr ...

s are shown squabbling when play gets out of hand, and one of them communicates real fright by urinating uncontrollably. Large herbivores that have horns or antlers are naturally inclined to use them to assert their dominance over the females in a herd. Duelling male

ibex An ibex (plural ibex, ibexes or ibices) is any of several species of wild goat (genus ''Capra''), distinguished by the male's large recurved horns, which are transversely ridged in front. Ibex are found in Eurasia, North Africa and East Africa ...

and Alaskan bull

moose The moose (in North America) or elk (in Eurasia) (''Alces alces'') is a member of the New World deer subfamily and is the only species in the genus ''Alces''. It is the largest and heaviest extant species in the deer family. Most adult ma ...

undergo some of the most ferocious engagements – sometimes to the death.

9. "Friends and Rivals"

Broadcast 28 November 1990, this instalment investigates the ways in which those animals that live in social groups interact with each other. The solitary

eagle Eagle is the common name for many large birds of prey of the family Accipitridae. Eagles belong to several groups of genera, some of which are closely related. Most of the 68 species of eagle are from Eurasia and Africa. Outside this area, j ...

is contrasted with

whooper swan The whooper swan ( /ˈhuːpə(ɹ) swɒn/) (''Cygnus cygnus''), also known as the common swan, pronounced ''hooper swan'', is a large northern hemisphere swan. It is the Eurasian counterpart of the North American trumpeter swan, and the type speci ...

s landing in Scotland after a 1,600-kilometre journey from

Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...

. Once arrived, they must battle for territory with those already there, and pairs or families are usually victorious. Attenborough uses a group of farmyard

chicken The chicken (''Gallus gallus domesticus'') is a domesticated junglefowl species, with attributes of wild species such as the grey and the Ceylon junglefowl that are originally from Southeastern Asia. Rooster or cock is a term for an adu ...

s to demonstrate a

pecking order In biology, a dominance hierarchy (formerly and colloquially called a pecking order) is a type of social hierarchy that arises when members of animal social groups interact, creating a ranking system. A dominant higher-ranking individual is so ...

Caciques A ''cacique'' (Latin American ; ; feminine form: ''cacica'') was a tribal chieftain of the Taíno people, the indigenous inhabitants at European contact of the Bahamas, the Greater Antilles, and the northern Lesser Antilles. The term is a Spa ...

are shown cooperating to deter predators, despite their fights amongst themselves to establish a pecking order. A pride of lions is shown co-operating to subdue a buffalo. Afterwards, each animal peacefully awaits its turn at the carcass.

Baboon Baboons are primates comprising the genus ''Papio'', one of the 23 genera of Old World monkeys. There are six species of baboon: the hamadryas baboon, the Guinea baboon, the olive baboon, the yellow baboon, the Kinda baboon and the chacma ...

s live in troops of up to 150, and their complex

dominance hierarchy In biology, a dominance hierarchy (formerly and colloquially called a pecking order) is a type of social hierarchy that arises when members of animal social groups interact, creating a ranking system. A dominant higher-ranking individual is so ...

is examined in detail.

Vampire bat Vampire bats, species of the subfamily Desmodontinae, are leaf-nosed bats found in Central and South America. Their food source is blood of other animals, a dietary trait called hematophagy. Three extant bat species feed solely on blood: the ...

s display

reciprocal altruism In evolutionary biology, reciprocal altruism is a behaviour whereby an organism acts in a manner that temporarily reduces its fitness while increasing another organism's fitness, with the expectation that the other organism will act in a similar m ...

by regurgitating

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...

for any neighbour that has missed out on a night's feeding. Dwarf mongooses live in family groups of around a dozen. While some look for food or sleep, others are always posted on the lookout for predators and quickly raise the alarm if necessary. Meanwhile, some of the most extreme co-operation is demonstrated by the underground

naked mole-rat The naked mole-rat (''Heterocephalus glaber''), also known as the sand puppy, is a burrowing rodent native to the Horn of Africa and parts of Kenya, notably in Somali regions. It is closely related to the blesmols and is the only species in the ...

, whose 80-strong clusters are divided into workers (who tunnel perpetually), soldiers (who only act when danger threatens), and a single queen for breeding. Leafcutter ants are shown transporting their food deep below ground: it has to be planted in a special

fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from t ...

to convert its indigestible

cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell w ...

into something edible, and each stage of the operation is carried out by a different caste of individuals.

10. "Talking to Strangers"

Broadcast 5 December 1990, this episode concentrates on animal communication. In

Kenya ) , national_anthem = " Ee Mungu Nguvu Yetu"() , image_map = , map_caption = , image_map2 = , capital = Nairobi , coordinates = , largest_city = Nairobi ...

, Attenborough accompanies a tribesman who calls to a honeyguide, which in turn answers him and leads the pair to a bees' nest. The tribesman extracts the

honey Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primar ...

, and some is left to reward the bird.

African hunting dog The African wild dog (''Lycaon pictus''), also called the painted dog or Cape hunting dog, is a wild canine which is a native species to sub-Saharan Africa. It is the largest wild canine in Africa, and the only extant member of the genus '' L ...

s are shown hunting

gazelle A gazelle is one of many antelope species in the genus ''Gazella'' . This article also deals with the seven species included in two further genera, '' Eudorcas'' and '' Nanger'', which were formerly considered subgenera of ''Gazella''. A third ...

s, of which the target is the individual that leaps lowest.

Lark Larks are passerine birds of the family Alaudidae. Larks have a cosmopolitan distribution with the largest number of species occurring in Africa. Only a single species, the horned lark, occurs in North America, and only Horsfield's bush lark oc ...

s evade merlin by sending a similar message: by continuing to sing while being chased, it tells the pursuer that its prey is fit and therefore will be difficult to catch (see

handicap principle The handicap principle is a hypothesis proposed by the biologist Amotz Zahavi to explain how evolution may lead to "honest" or reliable signalling between animals which have an obvious motivation to bluff or deceive each other. It suggests that ...

). (In 80% of cases this turns out to be true.)

Vervet monkey The vervet monkey (''Chlorocebus pygerythrus''), or simply vervet, is an Old World monkey of the family Cercopithecidae native to Africa. The term "vervet" is also used to refer to all the members of the genus ''Chlorocebus''. The five distinct ...

s' cries are among the most complex. Their utterances are effectively words: a vocabulary that defines each of their predators, so an

alarm call In animal communication, an alarm signal is an antipredator adaptation in the form of signals emitted by social animals in response to danger. Many primates and birds have elaborate alarm calls for warning conspecifics of approaching predator ...

is specific to a particular threat. Some creatures transmit their presence by display, and Attenborough observes thousands of

fireflies The Lampyridae are a family of elateroid beetles with more than 2,000 described species, many of which are light-emitting. They are soft-bodied beetles commonly called fireflies, lightning bugs, or glowworms for their conspicuous production ...

illuminating the darkness. Sounds travel faster and further underwater, and over 200 species of fish use them to communicate. In turn,

s have become adept at sensing their proximity. However, the most visual aquatic animal is the squid, which uses colour change and posture to communicate. Finally, Attenborough swims with spotted

dolphin A dolphin is an aquatic mammal within the infraorder Cetacea. Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (the ...

s. They converse with a series of

ultrasonic Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies fr ...

clicks, and each has a family call inherited from its mother: effectively a ' surname'. They also use normal sound, body posture and touch – in short, in terms of ability to communicate, they are

man A man is an adult male human. Prior to adulthood, a male human is referred to as a boy (a male child or adolescent). Like most other male mammals, a man's genome usually inherits an X chromosome from the mother and a Y chromo ...

's closest rival.

11. "Courting"

Broadcast 12 December 1990, this programme surveys the methods employed in attracting a mate, mainly those of birds. The Indian florican inhabits long grass, and so is difficult to see. In order to gain attention, it 'trampolines' in the same spot for up to 400 times a day.

Whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

s sing to their prospective partners, and the female's calls can be heard by suitors for over eight kilometres. When animals send out signals of attraction, they must also ensure that they don't entice the wrong species, and so have markings that differ prominently. Attenborough highlights the booby as an example: there are around half a dozen species, all of which may occupy the same island. However, the blue-footed booby reassures its chosen mate by continually lifting its feet.

Tropicbird Tropicbirds are a family, Phaethontidae, of tropical pelagic seabirds. They are the sole living representatives of the order Phaethontiformes. For many years they were considered part of the Pelecaniformes, but genetics indicates they are most cl ...

s and

marsh harrier The marsh harriers are birds of prey of the harrier subfamily. They are medium-sized raptors and the largest and broadest-winged harriers. Most of them are associated with marshland and dense reedbeds. They are found almost worldwide, excluding ...

s are shown providing graceful aerobatic displays, while the

sac-winged bat Emballonuridae is a family of microbats, many of which are referred to as sac-winged or sheath-tailed bats. They are widely distributed in tropical and subtropical regions around the world. The earliest fossil records are from the Eocene. Desc ...

uses a strong perfume to lure a companion. Among those birds that produce the most spectacular visual displays are the

lyrebird A lyrebird is either of two species of ground-dwelling Australian birds that compose the genus ''Menura'', and the family Menuridae. They are most notable for their impressive ability to mimic natural and artificial sounds from their environ ...

(which also has an elaborate song), the

peacock Peafowl is a common name for three bird species in the genera '' Pavo'' and '' Afropavo'' within the tribe Pavonini of the family Phasianidae, the pheasants and their allies. Male peafowl are referred to as peacocks, and female peafowl are r ...

, and the riflebird (and indeed most other

birds of paradise The birds-of-paradise are members of the family Paradisaeidae of the order Passeriformes. The majority of species are found in eastern Indonesia, Papua New Guinea and eastern Australia. The family has 44 species in 17 genera. The members of ...

). The bowerbird invites potential partners to inspect its bower: a specially prepared area that contains a hut or walkway augmented by strikingly coloured objects. The intricate dances performed by

manakin The manakins are a family, Pipridae, of small suboscine passerine birds. The group contains some 54 species distributed through the American tropics. The name is from Middle Dutch ''mannekijn'' "little man" (also the source of the different bird ...

s in

Trinidad Trinidad is the larger and more populous of the two major islands of Trinidad and Tobago. The island lies off the northeastern coast of Venezuela and sits on the continental shelf of South America. It is often referred to as the southernmos ...

are also examined. Finally, Attenborough observes the topi's display courts, whose sharply defined boundaries are jealously guarded by rival males.

12. "Continuing the Line"

Broadcast 19 December 1990, the final instalment illustrates how species fulfil their ultimate ''raison d'être'' and ensure that their

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

s are passed on to the next generation. It is a universal problem, but one which has given rise to a variety of solutions. Barnacles cannot move, but each has both

male Male (symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization. A male organism cannot reproduce sexually without access to ...

and

female Female ( symbol: ♀) is the sex of an organism that produces the large non-motile ova (egg cells), the type of gamete (sex cell) that fuses with the male gamete during sexual reproduction. A female has larger gametes than a male. Females ...

sex cells, allowing each neighbour to be a potential mate. On the other end of the scale, a female elephant undergoes a long

pregnancy Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occur ...

– 22 months – and so wishes to ensure that her calf is fathered by a strong and proven male. She is therefore very choosy about her partner. A female chinchilla is even more so, and rejects an unwanted suitor by squirting

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellular ...

in its face. Mating is a dangerous business when weapons are involved, and a male

tarantula Tarantulas comprise a group of large and often hairy spiders of the family Theraphosidae. , 1,040 species have been identified, with 156 genera. The term "tarantula" is usually used to describe members of the family Theraphosidae, although m ...

approaches his intended with trepidation. Only when he succeeds in holding off her poison fangs is he able to progress any further. For some, the right moments to get together are few and far between: a male crab, for example, must wait until a female

moult In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...

s her shell before he is able to fertilise her. Male sea lions are shown fighting over a

harem Harem ( Persian: حرمسرا ''haramsarā'', ar, حَرِيمٌ ''ḥarīm'', "a sacred inviolable place; harem; female members of the family") refers to domestic spaces that are reserved for the women of the house in a Muslim family. A har ...

, and some use the battle to their advantage by making off with reluctant females. Attenborough observes that the monogamous relationships enjoyed by humans are rare within the animal kingdom, but he highlights the royal albatross as a "beautiful" exception. The pair of birds featured met as five-year-olds, and have been together for twenty years.

Home media

The series is available in the UK for Regions 2 and 4 as a 4-disc DVD set (BBCDVD1428, released 27 September 2004) and as part of '' The Life Collection''. Erroneously entitled ''Trials of Life'', its sole extra feature is a 50-minute documentary: ''The Making of The Trials of Life''. It was previously released in 2002 as an abridged 3-disc set, with each episode cut to 35 minutes. The series was released on

Blu-ray The Blu-ray Disc (BD), often known simply as Blu-ray, is a digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and capable of st ...

in the UK on 12 November 2012. The accompanying book, ''The Trials of Life: A Natural History of Behaviour'' by David Attenborough (), was published by BBC Books on 4 October 1990 and was shortlisted for the 1991 Rhône-Poulenc Prize. It is currently out of print.

References

External links

* * {{DEFAULTSORT:Trials of Life, The 1990 British television series debuts 1990 British television series endings BBC television documentaries Documentary films about nature