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Humpback whales




Length: 12.2-14.6 m   (40-48 ft)**
Weight: 22.7-36.3 tonnes (25-40 tons)**


Length: 13.7-15.2 m   (45-50 ft)**

General characteristics

  • stocky, rounded body
  • massive head marked by protruberances containing hair follicles
  • 20-35** throat pleats / throat grooves /ventral pleats
  • 270-400** blackish baleen plates up to 80** cm long on each side of the upper jaw
  • huge pectoral fins (flippers) – up to 1/3 of the body length


  • black on dorsal side
  • mottled black and white on the underside – chin, throat, belly, fins, fluke
  • more white pigmentation seen on southern hemisphere individuals

Distinguishing features

  • long, slender flippers
  • ventral pleats
  • fluke – serrated on the trailing edge
  • fluke black and white on underside => individually marked

** different numbers are given by various authorities; I included them to give some idea of the dimension or scope of these features


For many of the humpback whale’s repertoire of behaviours, there is no known explanation.  Below are the most widely-reported acts and some of the suggested interpretations or what is known of the behaviour. Breaching launches 2/3 of its body out of the water, head first; falls back with a splash, often rolling onto side

  • dislodge parasites such as barnacles, whale lice, cookie-cutter sharks;
  • to get a view of the surroundings;
  • aggression;
  • long-distance communication;
  • exclamation mark at the end of another behaviour;
  • courtship display;
  • a way of herding fish;
  • play

Flipper slap

  • forcefully slapping the surface of the water with the flipper
  • communication

Flipper waving

  • while lying on its side, the whole flipper is raised above the water for up to an hour at a time
  • occurs in or near breeding areas

Head lunging

  • the head is thrust forcefully towards another whale in a threatening manner
  • aggressive posture to deter competitors

Head slap

  • whale forcefully hurls its head onto water surface
  • aggressive display

Tail lobbing

  • raising the fluke out of the water and then slapping it on the surface
  • communication;



Krill, sardines, mackerel, anchovies and other small schooling fish krill – a small crustacean like a miniature shrimp krill mating swarms can be huge – one hundred million tons


In polar waters feed in the top 100m (330ft) of the water column, where there are dense swarms of suitable plankton


In the cold waters during summer usually feed twice a day; the first feed occurs at dawn and is the larger very occasionally in warmer waters feeding may resume during migration to the polar seas

How much

Estimates vary but the range per whale per day is 1.3 – 4.1 tonnes (1.3 – 4.0 tons)


  • All oceans to the edge of the ice packs
  • Highly migratory between polar waters in summer and tropical / subtropical waters in winter tend to migrate along the same route each year
  • Northern & southern hemisphere whales never interbreed even where they use the same equatorial breeding grounds because their breeding seasons are 6 months apart
  • Groups mix during summer in polar waters


As whales are mammals, they posses general mammalian characteristics like breathing air, bearing live young and suckling them, maintaining their own body heat.

They have evolved from land-living ungulates, hoofed mammals; the changes involved in this path include :

  • streamlined body
  • forelimbs modified into flippers
  • hind limbs disappeared; tail flattened into two paddles for propulsion
  • development of insulating blubber also useful for buoyancy
  • breathe through a blowhole, on top of head; nasal plugs to close nostrils on diving
  • loss of hair
  • ability to hear underwater
  • eyes and kidneys adjusted to different salt balance


Humpback whales feed by opening their mouths and taking in large volumes of water, as much as 2275 litres (500 gallons) at a time, causing the pleated grooves in the throat to expand. The whale uses its large tongue to force water out through the baleen plates which act as a sieve, and leave the prey trapped in the hairy fringes of the plates.

A number of feeding methods have been described:

  • lying on side and swimming in tight circles with mouth partly open so that water flows out through the baleen as the whale swims and periodically closing its mouth to force out the remaining water
  • swim with the partially opened mouth in line with the water surface

Lunge feeding

  • whale comes up from the deep at an angle to the surface with mouth partially open and emerges before closing its mouth

Flick feeding

  • whale herds its prey into an accessible position, then flicks its tail forward splashing down in front of the school and startling the prey into stillness long enough for the whale to engulf the school

Bubble netting

  • All bubble netting methods are based on the whale expelling air to form a cloud of finely divided air bubbles.
  1. as the bubbles rise, the whale races through the bubbles with its mouth open
  2. appears to drive the prey against the bubbles and catch them as they retreat from the bubbles
  3. from below a concentration of prey, the whale circles slowly towards the surface blowing bubbles which eventually encircle the prey and prevent it from escaping; the whale emerges within the circle with its mouth open

Cooperative hunting

4-6 whales herd schools of prey and take turn lunging feeding



  • tend to winter in warm tropical or subtropical waters and summer in the polar regions BUT humpback whales have been seen in tropical waters in summer, and in cold water regions in winter
  • migratory patterns are predictable; animals tend to take the same route each year so that, for example, whales born on the east coast of Australia will tend to return along that route in ensuing years
  • migrations not a mass movement more like a very long procession with the immature subadults being the first to arrive, followed by the mature males, and then mothers and their calves
  • follow shorelines


  • move to the warm waters to mate and for the birth of calves BUT young calves have been seen in cold water regions

How far

Estimates of migration distances:

  1. round trip Alaska to Hawaii, 9500 kms (6000 miles)
  2. Antarctica to Australia 2500 kms (1500 miles)


  • Whales use the total geomagnetic field of the earth. This provides them with a simple map and timer to monitor their position and progress.
  • They follow magnetic contours.
  • Problems arise near shore as magnetic formations don’t end on the beach but may continue onto the land.
  • Strandings may be accidents in navigation that have occurred days before the actual stranding event and some distance from land. All of the live strandings in the UK have occurred at such places.
Nearest relatives
FamilyGenusSpeciesCommon name
 Balaenopteridae Rorquals :dorsal finventral pleats running from lower jaw to bellyBalaenopteraphysalusFin Whale
edeniBryde’s Whale
borealisSei Whale
musculusBlue Whale
acutorostrataMinke Whale
MegapteranovaeangliaeHumpback Whale

Observer hints

  • In many places, there are strict guidelines governing human behaviour in the presence of whales; these are in place to ensure the safety of both the whales and the watchers.
  • Some websites offer provide Whale Spotting Sheets for observers to complete.

External fauna


  • at least 3 different species;
  • especially under the chin and along the leading edge of the flippers;
  • grow to 6 cm in diameter;
  • drop off in warm water;
  • not a true parasite, gain no nourishment from the whale;
  • when whales fight, the barnacles inflict skin damage on the other whale

Whale lice, Cyamus boopis

  • small crustacean;
  • found in folds around eyes, flippers, throat grooves;
  • cause little damage to host;
  • commonly infect barnacles and callosities


  • copepod;
  • rope-like structure that dangles from the body

Sea Lampreys, Cookie-cutter Sharks

  • have lips like suction cups;
  • attach to passing whales;
  • bite out a cookie-sized piece of flesh;
  • leave whitish, oval-shaped scars


  • feed on dead skin and other organisms on the whale’s body; not

Internal parasites

  • rarely a cause of mortality
  • Roundworms stomach
  • Tapeworms, Thornheaded Worms intestine
  • Flukes lungs


  • Generally, none.
  • New-born, old, sick : killer whales, sharks – great white, tiger, hammerhead, various whalers


Competition between males

  • males compete for access to oestrous females
  • create bubble screens to hide females from competing males
  • whales of different pods join up to form new pods during fighting and mating
  • dominant males force weaker males from the pod
  • males threaten other males by lunging with their throat pleats extended, sideswiping with the flukes and tail stock, raising the head from the water while swimming, fluke slapping, flipper slapping, releasing bubbles to disorientate a rival
  • combatants can be left with raw and bleeding patches on their backs and fins

Signs of Courtship

  • rolling, slapping the water surface with flippers, fluke slapping, breaching


  • only 1 calf is born at a time, born fluke first, well developed after about 12 months gestation
  • length of 3-4.5 m (10-15 ft), weight of  0.9 tonnes (1 ton)
  • suckled underwater, close to the surface; milk is ejected into the mouth of the calf; milk is very rich in fat (45-60%), protein and lactose so that the calf will grow quickly
  • lactation lasts 4-11 months
  • calf stays close to mother for at least the first few day or weeks
  • other adults help protect calves from predators

Sexual Maturity

  • sexual maturity is determined by size rather than age:
    11-12m in males and 12m in females which corresponds to 4-12 years
  • a female breeds every second year or twice in three years, usually not every year

Social system

basic unit appears to be mother and calf ; this represents the longest association between individual whales

in the summer feeding grounds, the size of a group (1-20) will depend on the size of the prey patch


  • composed of moans, groans, roars, sighs, high-pitched squeaks and chirps
  • a sequence can last up to 30 mins and be repeated for hours
  • create noise by shunting air around the air spaces of the whale’s body
  • all whales in any one area at any given time produce the same sound sequences
  • each year’s song is different from the previous
  • song vary between stocks of humpback whales
  • only males sing – song may be a warning defining territory, an aggressive or courtship display
No special conservation statusglobal population increasing
World population estimates:**5,000-7,000
representing 15-20% of the original population
Local population estimates:Eastern Australia – 2000
North Pacific off Alaska – 2000
**I think the disparity between the estimates is due to the difficulty in making an estimation.


  • No one knows why whales become stranded.  It is likely that a range of reasons would be required to explain all strandings. Of the following suggestions, some are reasonable while others are unlikely:
  • suicide
  • entering shallow water to rest
  • brain infections
  • attempts to use ancient migration routes now closed by geological changes
  • noise from shipping
  • pollution
  • radar and electronic transmissions
  • phases of the moon
  • earthquakes and storms
  • navigation errors made using the earth’s magnetic field

Resources – books

These are just a few of the many sources of information available about the Humpback Whale

  • The Australian Guide to Whale Watching, Dalton T & Isaacs R, 1992. Weldon Publishing, Sydney.
  • Among Whales, Payne R, 1995. Charles Scribner’s Sons, New York.
  • Encyclopedia of Australian Wildlife, Reader’s Digest Australia Pty Ltd, 1997. Reader’s Digest (Australia) Pty Ltd, Surrey Hills.

Riversleigh – preserving a record of evolution in Australia


By Dr Bernie Cooke of the School of Natural Resource Sciences, Queensland University of Technology, Brisbane, Australia. Dr Cooke has been on numerous expeditions to Riversleigh and has worked for many years on the fossils that the site has given up. He currently lectures on biodiversity and the evolution of Australian biota.

Evolution in Australia

Australia is a continent of contrasts. Its interior is brown, burnt by the sun and parched for water, but its margins are kinder to life and support most of its human population. Its plants and animals are for the most part quite different to those of the rest of the world – not surprising really, since they are the product of tens of millions of years of evolution on an island continent, isolated for that great span of time from contact with other large land masses.

Evolution in Australia followed a different course and produced very different creatures, perhaps none more so than its mammals. While the rest of the world contents itself with one, or at the most, two major kinds of mammals, Australia has three: two monotremes – the platypus and echidna, many, many marsupials (not just kangaroos and koalas), but only a few of the placental mammals so dominant in the rest of the world. Apart from the dingo, which appears to have arrived in Australia only thousands of years ago, the continent’s only native placental mammals are rats and bats.

Australian vertebrate fossils

Until very recently, not much was known about the evolutionary history of Australia’s unique mammal fauna. Soon after European’s settlement in Australia, discoveries were made which showed that even more unusual mammals had once lived here.

These included giant plant-eating marsupials as big as a rhinoceros, giant long-armed kangaroos with short blunt faces and even leopard-sized meat-eaters, related not to modern meat-eating marsupials but to plant-eating possums.

Animals such as these became extinct as recently as the end of the last ice age, a time when Australia was at its most arid. Unfortunately the history of these animals could be traced back through the fossil record no more than a few million years. The kinds of land animals that lived in Australia earlier than that could only be imagined.

By Black KH, Camens AB, Archer M, Hand SJ – Black KH, Camens AB, Archer M, Hand SJ (2012) Herds Overhead: Nimbadon lavarackorum (Diprotodontidae), Heavyweight Marsupial Herbivores in the Miocene Forests of Australia. PLoS ONE 7(11): e48213. doi:10.1371/journal.pone.0048213, CC BY 2.5

Fossil discoveries at Riversleigh

All that has changed in the last decades with new discoveries of fossil mammal remains in several sites in the Australian outback. The most spectacular of these discoveries was made at Riversleigh, an isolated cattle station in the far north-west of Queensland.

Here, Professor Michael Archer and a team of researchers from the University of New South Wales and other Australian institutions are resurrecting the bones of a vast array of vertebrate animals entombed in deposits of freshwater limestone.

Riversleigh is Australia’s most important source of information about the evolutionary history of its vertebrate animals. Well over a hundred different fossil sites are now known from an area covering tens of square kilometres. In them are preserved in sometimes stunning detail, the remains of animals as diverse as lungfish, frogs, crocodiles, turtles, snakes, lizards, birds (including giant, flightless birds), marsupials, bats, rats and even insects and other arthropods.

It is not just the diversity and sheer numbers of animal remains preserved that makes Riversleigh so important to science, but the fact that different Riversleigh sites preserve glimpses of life at different ages in the past – from as long ago as about twenty-five million years through to yesterday afternoon. The Riversleigh fossil deposits are of such importance to Australia and the world that they have been given World Heritage listing

Why so many Riversleigh fossils?

Why are so many animal remains preserved so well at Riversleigh? The answer to that lies in the underlying rocks which are also limestone, but laid down in the bed of an ancient sea more than five hundred million years ago.

As these rocks were exposed on what became land, rainwater began to dissolve them. The limestone-charged run-off flowed into pools, streams and lakes.

Water also carved out extensive cave systems, ideal roosts for bats and shelters for other animals. Sometimes holes in the cave roofs formed pit traps for unwary animals. The flesh decayed from the bodies of animals which died in or were washed into caves and pools, streams and lakes. The limestone rich waters quickly encased the bones in new layers of limestone, sealing them from view, but preserving and protecting them from damage for millions of years.

  • The author escaping from a small sinkhole
  • Henk Godthelp of the University of New South Wales, preparing to descend a deep sinkhole in the Riversleigh limestone.

Recovering fossils from Riversleigh

The process of recovering fossils at Riversleigh begins by first of all finding them. This is done by close inspection of the limestone rock, looking for traces of bones or teeth. In their fossilized state these are more resistant to weathering than the rock which encases them.

As water dissolves the rock, bones and teeth can be seen protruding from the rock. Releasing them from the rock is not so easy. Quarrying techniques must be used, including the occasional use of light explosives. Many of the areas are so inaccessible that the larger rocks have to be broken up with sledge hammers, bagged and labeled and lifted out by helicopter.

Once they finally reach the laboratory, the fossils are freed by dissolving away the surrounding limestone with dilute acetic acid. After treatment with preservatives, the fossils are then ready for study by scientists.

Further changes in the fauna are revealed in Pleistocene deposits on sedimentary terraces of the Gregory River. Here are preserved representatives of the marsupial megafauna, giant kangaroos and bullock-sized browsers, all extinct by seventeen thousand years ago.

A bandicoot skull exposed on a broken piece of limestone. The darker region is where the skull roof has been broken to expose a fossil cast of its brain, preserving even the pattern of blood vessels on its surface.

  • Bandicoot skull

A partial but articulated skeleton of a sheep-sized diprotodontid – a browsing marsupial. Remains of more than two dozen individuals opf this species have been recovered from a single small site.

  • Diprotodontid skeleton

Pieces of the skull of an ancient kangaroo, revealed when a limestone boulder was broken open. The same skull after repair and acid etching to remove the encasing limestone.

  • Ancient kangaroo skull
  • Repaired skull

Ancient environments of Riversleigh

Studies so far reveal a staggering number of different kinds of animals preserved at Riversleigh. The diversity of animal life in its older sites (late Oligocene/early Miocene) is far greater than that known from Australia to-day, even in the tropical rainforests of northern Australia where diversity is at its highest.

The kinds of land animals in these older sites include many varieties of leaf-eating possums, lots of ground-dwelling browsing animals such as kangaroos and now extinct diprotodontids, together with many different omnivorous bandicoots.

Such a variety of animals could only have survived in a stable habitat containing a wealth of food sources supporting specialist as well as generalist feeders. Modern rainforests provide such conditions and it is thought that these ancient animals also lived in a rainforest environment. Significantly, many of these older Riversleigh animals have modern descendants which still live only in rainforests. As the accompanying photographs show, the rainforests are long gone from Riversleigh, the result of increasing aridity in Australia after about mid-Miocene times (about fifteen million years ago). Fossil remains in younger Riversleigh deposits reflect that change – species diversity decreases and some kinds of animals become extinct and are replaced by others better adapted to drier conditions.

Exposed high on the cliffs which confine the upper reaches of the Gregory River at Riversleigh, is an ancient cave floor from five million years ago. Remains of animals from here include more modern grass-eating kangaroos, demonstrating the spread of grasslands as the interior of Australia became increasingly arid. Also preserved in this deposit are remains of rats – which had at that time recently invaded Australia from Asia.

These fossil rat bones are remains of the midnight feasts of the large, carnivorous ghost bats who roosted in the cave by day and hunted rats and other small animals by night. The bats have a much longer history in Australia than the rats, occurring in their millions in many of the older Riversleigh sites. Interestingly, some of Riversleigh’s leaf-nosed bats have close relationships with those known from Oligo-Miocene deposits in France.

Odd animals of Riversleigh

While the ancestors of most of Australia’s modern vertebrate animals are preserved at Riversleigh, it also preserves remains of animals whose existence no one had suspected. Two of these were so bizarre that no existing names could be applied to them and they became known among the researchers as Thingodonta and Weirdodonta.

Both now have respectable scientific names: Yalkaparidon and Yingabalanara respectively. They are however, the only known representatives of two whole families of marsupials, the Yalkaparidontidae and Yingabalanaridae, both of which have no modern descendants. Each year a new expedition goes to Riversleigh and each year new sites are found and new surprises uncovered.

Work at Riversleigh will no doubt continue for long after the present generation of researchers have begun their own process of fossilization. Undoubtedly Riversleigh will continue to surprise and delight new generations of scientists and provide us all with a greater insight into the history of life on our island continent.

More information

If you would like to know more about Riversleigh and the research associated with it read the book! Archer M, Hand SJ and Godthelp, H. 1991. Riversleigh. Reed Books Pty Ltd, Sydney.

If you would like to support research at Riversleigh, consider membership of its support group, the Riversleigh Society – application forms available from their website above.

Celebrations for Riversleigh’s 25 years as a World Heritage site (ABC Science Show 24th August 2019)

It is a dry rocky landscape in north western Queensland. Stage coaches would stop by a large rock allowing passengers a comfort stop.  Little did anyone know they were relieving themselves on a rich fossil bed. Hundreds of new species have been described from thousands of well-preserved specimens, changing our understanding of the origins, evolution and history of Australia’s vertebrates. These include ancestors of kangaroos, rat-kangaroos, bandicoots, wombats, marsupial moles, thylacines, dasyurids, koalas, possums, pygmy possums, cuscuses, bats, rodents and platypuses and the now extinct diprotodontids, thylacoleonids, ilariids and wynyardiids. In addition to mammals there are crocodiles, snakes, lizards, turtles, lungfish, frogs, birds, snails, insects and other invertebrates. Riversleigh was declared a World Heritage site in 1994

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