Whales
Seen a whale? Call the Whale Hotline
- 0427 – WHALES
- (0427 942 537)
Call this number to report: whale sightings in Tasmanian waters, whale or dolphin strandings, injured whales, dolphins or seals, strange or unusual marine mammals and turtles.
Our attitudes towards whales have undergone a massive change in the past few decades. Growing worldwide concern for these gentle marine creatures has fuelled the transition from a commercial exploitation that severely depleted the global population of large whales to an almost universal ban on whaling. Today, a rapidly growing tourist industry provides people with the opportunity to see these remarkable animals in their own environment, while instances of mass strandings bring great public support in efforts to return the animals to the sea. (See our page on whale strandings - how you can help)
Biology
Whales, of course, are mammals. Like their land-based cousins, whales are warm-blooded, breathe air and suckle their young on milk. Some species possess hair, particularly around the mouth, but in most species hair has been lost to minimise drag. Whales and dolphins belong to a group of mammals collectively known as cetaceans and are believed to share a common ancestry with the ungulates, a diverse group of hoofed mammals that includes modern-day horses, pigs, sheep, deer, antelopes and camels. Their land-based ancestors adopted a marine existence over 50 million years ago.
Cetaceans are divided into two groups -- the baleen whales and the toothed whales. The toothed whales, as their name suggests, use teeth for feeding, possess only one blowhole opening and have asymmetrical skulls. Baleen whales use baleen (a rigid, keratin-like material similar to our fingernails) which hangs in vertical strips from the upper jaw. Baleen acts like sieves to filter out the tiny crustaceans (krill) on which they feed. Large whales, such as the humpback, can consume over two tonnes of krill each day.
A number of feeding strategies are used to maximise the intake of krill. A remarkable example is the 'bubble-netting' behaviour of the humpback whale, in which the animal expels a stream of bubbles from the blowhole while slowly ascending in a spiral to the surface. The bubbles form a cylindrical wall which surrounds the krill and traps them. The whale then swims upwards through the cylinder with its mouth open, consuming the concentration of krill.
Adaptations to the marine environment
Many aspects of cetacean biology reflect their adaptation to the marine environment. Increased size and the development of a thick, insulating layer of fat, or blubber, allows whales to maintain a constant body temperature despite the cold environment in which they often live. The buoyancy provided by water has led to decreases in bone density and a reduction of supportive tissues for internal organs. Because of this, large, stranded whales are in a perilous situation. Their bones can break easily and damage can occur to internal organs due to increased pressure. Whales must come to the surface to breath, although species such as the sperm whale have been known to remain submerged for over 1 1/2 hours and dive to depths in excess of two kilometres. The blow of a whale is the result of expired air (not water) and an oily residue secreted from the lining of the windpipe being forced out through the blowhole. The particular size and shape of the blow can be used as an aid to identification of the species.
Most species of toothed whale are able to use echolocation to form what is effectively a mental picture of their surroundings. These whales produce pulses of very high frequency sound which strike objects and return as echoes. From these echoes, the animal is able to gain detailed information on the size, shape, distance, and even texture of the objects around them. It is believed that the spectacular behaviour known as breaching also serves as a means of communication. Whales such as the humpback often smack the surface of the water with their tail to warn of danger.
Cetaceans in Tasmanian waters
The most frequently seen cetaceans are the common and bottle-nosed dolphins. Among the larger species of baleen whale, southern right whales and humpback whales can be seen at east coast vantage points such as Frederick Henry Bay and Great Oyster Bay. While most species migrate some distance off the continental shelf, the humpback and southern right whale come sufficiently close to the coast to allow regular sightings from land. Humpbacks travel northward to breeding areas off the coast of Queensland and Western Australia between May and July and return southward to their sub-antarctic feeding grounds between September and November.
Southern right whales travel north from June to September to the waters of southern mainland Australia and return southward between September and late October. A proportion of the population gives birth in Tasmanian waters. Most sightings occur on the east coast. Although this may be simply a consequence of the higher population of human observers in the east, it is likely that the humpback and southern right whales prefer the calmer waters of the east coast.
Research
The Parks and Wildlife Service is currently assisting in research into the recovery of the southern right whale. Along with many other species, the southern right whale suffered massive population declines during the years that commercial whaling ventures operated in Australia, with an estimated 26 000 individuals taken from southern waters of Australia and New Zealand. Today, only some 500-700 southern right whales migrate to the southern waters of Australia, but numbers are increasing.
The stranding record provides an indication of the species that occur in Tasmanian waters. Some species have been recorded only once and have never actually been observed live in Tasmanian waters.
Further information on why whales strand, and what you can do to help, can be found here. The following table presents the Tasmanian stranding record to the end of October 2003.
Tasmanian stranding record up to the end of October 2003
Toothed Whales
| Common name |
Scientific name |
No. of recorded animal strandings |
Total no. of animals stranded |
| Common dolphin |
Delphinus delphis |
115 |
457 |
| Sperm whale |
Physeter macrocephalus |
54 |
277 |
| Long-finned pilot whale |
Globicephala melaena |
68 |
2768 |
| Bottle-nosed dolphin |
Tursiops truncatus |
81 |
146 |
| Strap-toothed whale |
Mesoplodon layardi |
18 |
18 |
| False killer whale |
Pseudorca crassidens |
18 |
534 |
| Grays beaked whale |
Mesoplodon grayi |
18 |
18 |
| Cuviers beaked whale |
Ziphius cavirostris |
16 |
16 |
| Killer whale or orca |
Orcinus orca |
8 |
16 |
| Hectors beaked whale |
Mesoplodon hectori |
7 |
7 |
| Southern right whale dolphin |
Lissodelphis peronii |
2 |
2 |
| Pygmy sperm whale |
Kogia breviceps |
4 |
5 |
| Dusky dolphin |
Lagenorhynchus obscurus |
5 |
7 |
| Spectacled porpoise |
Phocoena dioptrica |
2 |
2 |
| Unidentified dolphins |
Unidentified Delphinidae |
29 |
274 |
| Arnouxs beaked whale |
Berardius arniuxi |
1 |
1 |
| Southern bottle-nosed whale |
Hyperoodon planifrons |
2 |
2 |
| Dense-beaked whale |
Mesoplodon densirostris |
2 |
2 |
| Risos dolphin |
Grampus griseus |
1 |
1 |
| Andrew's beaked whale |
Mesoplodon bowdoini |
3 |
3 |
| Shepherd's beaked whale |
Tasmacetus shepherdi |
1 |
1 |
| True's beaked whale |
Mesoplodon mirus |
1 |
1 |
| Unidentified beaked whale |
Unidentified Ziphiidae |
1 |
1 |
Baleen Whales
| Common name |
Scientific name |
No. of recorded stranding occasions |
Total no. of animals stranded |
| Pygmy right whale |
Caperea marginata |
67 |
70 |
| Minke whale |
Balaenoptera acutorostrata |
15 |
15 |
| Humpback whale |
Megaptera novaeangliae |
8 |
8 |
| Southern right whale |
Eubalaena australis |
3 |
3 |
| Sei whale |
Balaenoptera borealis |
2 |
2 |
| Fin whale |
Balaenoptera physalus |
3 |
3 |
| Brydes whale |
Balaenoptera edeni |
1 |
1 |
Further Information
There are numerous web sites with further information on whales. These include:
Other publications include:
Dalton, T. and Isaacs, R. (1992). The Australian Guide to Whale Watching. Weldon Publishing, Sydney.
Evans, P. G. H. (1987). The Natural History of Whales and Dolphins. Facts on File Publications, New York.
Tucker, M. (1989). Whales and Whale Watching in Australia. Australian National Parks and Wildlife Service.