Animal Species:Bull Shark, Carcharhinus leucas Valenciennes, 1839

The Bull Shark is one of the few sharks that are potentially dangerous to people and is probably responsible for most of the shark attacks in and around Sydney Harbour.

The species is also the only widely distibuted shark that stays in fresh water for long periods of time to feed and breed. Females sometimes give birth in river mouths were the young will live for up to 5 years.

Standard Common Name

Bull Shark

Alternative Name/s

The Bull Shark has also been called the River Shark, Freshwater Whaler, Estuary Whaler and Swan River Whaler.

Identification

The Bull Shark can be recognised by a combination of characters including a stout body, short blunt snout, triangular serrated teeth in the upper jaw and no fin markings as an adult. The species has a second dorsal fin about one third the height of the first, a small eye, and no skin ridge between the two dorsal fins. It is grey above and pale below, sometimes with a pale stripe on the flank.

Size range

The species grows to a length of 3.4 m.

Distribution

This species has a widespread distribution in tropical and warm temperate waters worldwide. In Australia the Bull Shark occurs from south-western, Western Australia, around the northern coastline and down the east coast to the central coast of New South Wales.

The map below shows the Australian distribution of the species based on public sightings and specimens in Australian Museums.  Source: Atlas of Living Australia.

Carcharhinus leucas

Distribution by collection data

Ozcam map of Bull Shark specimens in the Australian Museuma.

What does this mean?

Habitat

The Bull Shark can live in a wide range of habitats from coastal marine and estuarine, to freshwater. It has been recorded from the surf zone down to a depth of at least 150 m. It is the only species of shark that is known to stay for extended periods in freshwater. It has been reported nearly 4000 km from the sea in the Amazon River system, and is known to breed in Lake Nicaragua, Central America.

Feeding and Diet

It has an omnivorous diet which includes fishes (including other sharks), dolphins, turtles, birds, molluscs, echinoderms and even terrestrial mammals including 'antelope, cattle, people, tree sloths, dogs and rats’ (Compagno, 1984; 480).  They possibly even bite horses ... (see link attachment in comment from Local, below).

Economic/social impacts

It is an aggressive species that is considered dangerous to humans. Some authors consider that the Bull Shark may be more dangerous than the White Shark and the Tiger Shark. This is because of the Bull Shark's omnivorous diet and habitat preferences. The species may be found in murky water, where the splashing of a swimmer could be mistaken for a struggling fish.

The 2.8 m long fish in the images was caught on 18 February 1999, in a commercial fishing net near Grotto Point, Middle Harbour (Sydney Harbour) by T. and V. Depasquale and S. Virtu. This catch was a most unusual occurrence which attracted significant media interest. The specimen was on display at the Sydney Fish Markets for a week (where the images were taken) before it was donated to the Australian Museum by G. Costi (De Costi Seafoods). The specimen is now registered in the Australian Museum Fish Collection (AMS I.39432-001).

Classification

Species:
leucas
Genus:
Carcharhinus
Family:
Carcharhinidae
Class:
Chondrichthyes
Subphylum:
Vertebrata
Phylum:
Chordata
Kingdom:
Animalia

What does this mean?

References

  1. Compagno, L. 1984. FAO species catalogue. Vol. 4. Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Part 2. Carcharhiniformes. FAO Fish.Synop., (125) Vol.4, Pt.2: 251-655.Last, P.R. & J.D. Stevens. 1994. Sharks and Rays of Australia. CSIRO. Pp. 513, Pl. 1-84.
  2. Hutchins, B. & R. Swainston. 1986. Sea Fishes of Southern Australia. Complete Field Guide for Anglers and Divers. Swainston Publishing. Pp. 180.
  3. Last, P.R. & J.D. Stevens. 2009. Sharks and Rays of Australia. Edition 2. CSIRO. Pp. 644, Pl. 1-91.
  4. Paxton, J.R. 2003. Shark nets in the spotlight. Nature Australia. Spring. 27 (10): 84.


Mark McGrouther , Collection Manager, Ichthyology
Last Updated:

Tags fish, ichthyology, Bull Shark, Carcharhinus leucas, dangerous, Carcharhinidae, fresh water, marine, adult, shark attack, River Shark, Freshwater Whaler, Estuary Whaler, Swan River Whaler, stout body, short blunt snout, triangular serrated teeth, no fin markings, small eye, grey, pale underside, pale stripe, > 2m,

18 comments

Mark McGrouther - 11.06 AM, 30 June 2011

A long term Mt Crosby resident and fisherman reports that there were well known barbed wire hazards in the river near Kholo Crossing that may have caused the injury to the horse. He says members of the local freshwater fishing association have never noted Bull Sharks above the weir, despite many being active on this part of the river for over 50 years.

Mark McGrouther - 1.04 PM, 15 April 2011

Hi again Local.  Apologies.  I did not see that your message had an attachment.  Thank you for adding that!  Were there any tooth fragments in the wound.  As I mentioned before, I am curious if anything was published about the incident.  I'd like to be able to cite a reference on this page.

Mark McGrouther - 1.04 PM, 15 April 2011

Hi Local.  That's an interesting account.  Thank you for your comment.  I had not heard of this before.  Are you a veterinarian and do you have any documentation of the incident.  I don't necessarily want to add gorey photos to the website!

Local - 9.04 PM, 14 April 2011
I would like to mention that I have treated a horse that was swimming upstream of the Mt Crosby weir, that had shark bite wounds on it. Be careful they are happily living in the freash water.

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johnson - 10.10 AM, 06 October 2010

Pleased to be of assistance Bandicoot. FYI there is an article in the Queensland Museum book "Wildlife of Greater Brisbane" (2007 edition) entitled 'Sharks in the Brisbane River' (pages 177-179) which you may find informative.  

bandycoot - 7.10 PM, 05 October 2010
Thanks very much for the information. It is wonderful to get an answer to a question that is difficult to phrase correctly. Particularly so, when a few kilometres or decades would have a different outcome. We often kayak and occasionally swim in the Brisbane River well above the Mt Crosby Weir. It is an almost pristine environment and it is gratifying to know we share it with platypuses and tortoises rather than bull sharks.
johnson - 12.10 PM, 05 October 2010
Regarding Bandicoot's query, Bull Sharks are highly unlikely to be found above the Mt Crosby Weir in the Brisbane River. Prior to the weirs construction in 1926, large Bull Sharks were recorded as far upstream as Lowood. However sharks are unable to traverse the long narrow fish ladder to get over the weir, and during very large floods when the water overtops the weir, sharks generally migrate downstream toward the mouth, rather than upstream. In other unrestricted streams bull sharks will certainly penetrate long distances into freshwater and remain there for extended periods, however the weir is a powerful deterrent for this in the Brisbane River. Juvenile sharks up to about 1.2m in length are common in the Brisbane River, between the mouth and the lower side of the weir, but larger specimens exceeding 2m are also sometimes seen.
Mark McGrouther - 8.09 AM, 27 September 2010

Hi Syra,  Thank you for your comment.  I was very interested to read your statement that the Bull Shark "pumps more testosterone than a bull elephant".  That's an interesting statistic that I have not heard of before.  Can you please tell me where you read/heard this?

syra - 4.09 PM, 24 September 2010
One of the most dangerous shark is The Bull shark which is mattacks more or less anything, pumps more testosterone than a bull elephant and attacks more humans than any other shark. The bull shark likes murky water and has a higher tolerance to fresh/brackish water than other shark species which is why they can be found swimming in rivers. People often don’t expect sharks in rivers where, to make things worse, the water is often muddy and unclear. They often swim into rivers such as the Mississipi and the Ganges.
Mark McGrouther - 3.09 PM, 20 September 2010

Hi bandycoot. I guess the first thing to say is that as you know, the chance of being attacked by any sort of shark is very remote indeed.  Having said that, many people regard the Bull Shark as the most dangerous species to humans because the species has an aggressive nature, powerful jaws, non-specific diet and can live in a wide range of habitats that include often turbid, estuarine and freshwater habitats. Last and Stevens, 2009 (see references) state that the Bull Shark "penetrates far into fresh water for extended periods, where it occasionally even breeds. It can tolerate hypersaline conditions (up to 53 parts per thousand in the St Lucia lake system in South Africa) and is often found in turbid waters.  It has been reported from numerous freshwater systems in warm temperate Australia, including the Fitzroy, Ord, Adelaide, Daly, East Alligator, Mitchell, Normanby, Herbert, Brisbane, Clarence and Swan Rivers and Lake Macquarie.  Unfortunately I don't know the area that you refer to well enough to be able to comment with any authority.  I will email my colleague who works at the Queensland Museum and ask for his opinion.

bandycoot - 5.09 PM, 19 September 2010
I've been searching the web for information on Bull sharks and came across a Catalyst program with some information. I do a lot of kayaking on the Brisbane River and was told by an unreliable source that Bull sharks occur between Wivenhoe Dam and Mt Crosby. The source said that he used to swim in the Brisbane River near Fernvale but now only swims in Wivenhoe Dam for fear of being attacked by Bull sharks. The Catalyst program concluded with the following quote when referring to the Brisbane River. "Narration: So next time its a sweltering hot day and the river looks inviting, remember that when you enter the water, whether its fresh or salt, that you are entering the domain of animals that we are only just beginning to understand." I would have thought it unlikely for Bull sharks to ever be found upstream of Mt Crosby. My searching the web indicated that they can swim enormous distances upstream including up rapids. The only time conditions would allow this on the Brisbane River is during a serious flood. If Bull sharks managed to swim upstream in such a flood would they survive in that habitat after the flood was over? If you cannot give a definitive answer an indicative answer would suffice. Regards bandycoot.
Mark McGrouther - 8.03 AM, 19 March 2010

Hi Kels,  Your question is a tough one to answer.  I would suggest that a species is 'native' to anywhere it has not been introduced or 'recently' colonised.   To my knowledge the Bull Shark's widespread distribution is a natural phenomenon and thus it is 'native' throughout its distribution.  This may seem a little strange when you compare it to the native distribution of a terrestrial plant or animal that is endemic to (only found in) one particular region.  I hope this helps.

kels96 - 5.03 PM, 18 March 2010
Hi Im doing an assignment on a bull shark and I was wondering where are they NATIVE to? I know that there found all around the world, but were are they native to? please help... thnx, kels
loverboy - 1.03 PM, 18 March 2010
thats a big bull shark man i would not want to mis with that shark
Mark McGrouther - 9.07 AM, 13 July 2009
Thanks for submitting the photo Jonathan and for your comments to Maddy. I've never seen a Bull Shark underwater. That must have been pretty exciting!
Jonathan - 6.07 PM, 10 July 2009
Hi Maddy. If you click on the below link, it's an up close and personal photo of a bull shark that I took while scuba diving in Fiji. Diving is a great way to meet sharks. Most are not dangerous to humans. This shark was big. Not a great photo, but he was definitely close.

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Mark McGrouther - 10.07 AM, 10 July 2009
Hi Maddy, Thank you for your comment. Yes, sharks are fascinating. I am still adding shark pages to the website, so you should check the site regularly. You can query all the shark fact sheets on the website by entering the following url: /animalfinder/Shark-ray-and-chimaera-finder?Finder.StandardCommonName=shark&Finder.Species=&Finder.Genus=&Finder.Family=&x=0&y=0.
madmaddy15 - 10.07 AM, 10 July 2009
i'm only 10 and i want to learn about sharks for the future so throw anything and everything you've got at me i been studying the biggest shark the worlds ever seen like megalodon and have heeps of pictures theres 1 that always catches my eye a one where hes eating a dinosaur i don't really think it's real because who would be able to take a picture of a dinosaur but if megalodon is real he's he's still alive which means he's like 310 million years old from maddy P.S if you want to see pictures of him type into google biggest sharks ever.

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