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Like other dangerous predators, crocodilians cause reflexive fear in humans,
perhaps because the fear of being eaten is greater than the fear of being
bitten. Many animals will bite, but only a few see humans as prey to be eaten.
Of the 23 species of crocodilian, 8 are known to carry out unprovoked attacks on
humans. Of these species, attacks by the Saltwater crocodile (C. porosus),
Nile crocodile (C. niloticus) and American alligator (A.
mississippiensis) are best known. Less commonly implicated in attacks are;
Black Caiman (M. niger), Morelet’s crocodile (C. moreletii),
Mugger crocodile (C. palustris), American crocodile (C. acutus)
and the Indian Gharial (Gavialis gangeticus). Two unprovoked, directed
attacks by Australia Freshwater Crocodiles (C. johnstoni) on humans are
considered to have been cases of mistaken identity.
The incidence of crocodilian attacks on humans in many countries is very
difficult to quantify. There is little doubt that many more people are attacked
than is reported, as many attacks occur in remote areas. Accurate data
collection does not usually occur until a species is legally protected and
formal monitoring is introduced. For example, in northern Australia, details of
Saltwater crocodile attacks prior to 1971 (when the species was protected) are
lacking, yet records after 1971 are detailed and complete. Interestingly, the
recent increases in reports of attacks by Saltwater crocodiles in Papua New
Guinea are thought to be in part due to better communication being available to
people living in remote areas - namely mobile telephones!
Why do crocodilians attack humans?
Reasons why crocodilians attack humans without any provocation are thought to
be:
1.
Hunting for food: All crocodilians are opportunistic feeders, eating a wide
range of prey. With increasing body size, crocodilians shift to larger prey, and
humans are well within the size range of prey that can be taken by crocodilians.
2.
Defence of territory: Some species, such as Saltwater crocodiles, are highly
territorial, and will defend their territory against intruders, including
humans.
3.
Defence of nest and/or young: Most crocodilian species exhibit some form of nest
defence. The exception is Australian Freshwater crocodiles which in the wild do
not defend their nest, but may do so when in captivity. At the other extreme,
female Saltwater crocodiles will vigorously defend their nest to deter predators
and/or intruders, whereas other species are far less likely to do so against
humans. Crocodilians will also react to distress calls (vocalisations) made by
their young.
4.
Mistaken identity: It is possible that some attacks may be directed at dogs or
other animals accompanying people, with the latter were bitten by mistake.
Statistics
The most comprehensive datasets on attacks are available for the Saltwater
crocodile (C. porosus), Nile crocodile (C. niloticus) and American alligator (A.
mississippiensis). Some of the available data on unprovoked attacks by these
species have been summarised here to provide a comparison. Most data for the
Saltwater crocodile and the American alligator are drawn from single sources
respectively, but data for Nile crocodile are from a variety of sources.
Parameter
Saltwater
Crocodile
Nile
Crocodile
American
Alligator
% of attacks that were fatal
25% (Australia)
50% (Malaysia)
63%
<6%
Average age of victims
31 y
37 y
34 y
% of victims that were males
75%
59%
84%
% of attacks that occurred during the day
70%
86%
64%
Average crocodilian size (fatal attacks)
4.3 m
3.5 m
3.0 m
Size range (fatal attacks)
2.7-5.1 m
2.5-5.0 m
1.7-3.8 m
Average crocodilian size (non-fatal attacks)
3.0 m
3.0 m
2.0 m
Size range (non-fatal attacks)
1.7-5.0 m
1.8-5.0 m
0.6-3.7 m
Time of year for majority of attacks
Nov-Apr
Nov-May
May-Sep
Season of year for majority attacks
warm, wet
warm
warm
% of total attacks occurring in peak months
52%
78%
75%
% people swimming/wading/at waters'edge
81%
92%
90%
Avg. no. of attacks per year (2000-07)
3.6 (Australia)
275-745
10.6 (Florida)
Avg. no. of attacks per year (2000-03)
2.8 (Sarawak)
-
-
Avg. no. of attacks per year (2000-04)
-
-
-
Mass Attack?
The worst mass attack by crocodiles allegedly occurred on the night of 19
February 1945, when approximately 1000 Japanese soldiers found themselves pinned
down in a mangrove swamp separating Ramree Island from the Burmese mainland.
Only 20 Japanese allegedly escaped alive from the Saltwater crocodiles in the
swamp. However, the veracity of this report has recently been questioned.
Maneaters
A 5.8 m long Saltwater crocodile named “Whiteback” (due to distinctive white
markings on his back) gained considerable notoriety in Sarawak, Malaysia, after
killing 13 people. After years of failed attempts, Whiteback was finally caught
in May 1992 after he had claimed his last victim – a 30-year-old woman.
Whiteback is one of many documented man-eating crocodiles from Sarawak. The
local Iban people generally tolerate crocodiles, even large ones, until they
kill a person.
Most Attacks
There is little doubt that the Nile crocodile is responsible for more attacks on
humans than any other crocodilian species. After lions and hippos, the Nile
crocodile causes the highest numbers of wildlife-related fatalities in Africa.
It is difficult to estimate the total number of attacks per year as many
non-fatal attacks go unreported, but it is believed to exceed 300 per year since
the year 2000 (eg Namibia 8/y; Zambia 22/y; Kenya 13/y).
Although responsible for far fewer attacks, the Saltwater crocodile appears to
get relatively more media attention, perhaps due to the large sizes that male
“salties” reach (>5.1 m). The number of attacks by Saltwater crocodiles,
throughout the species’ range, is estimated to be around 20-30 per year in
recent years.
In many countries, numbers of attacks are increasing, largely due to increasing
(recovering) populations of crocodilians.
Average number of American alligator attacks per year for 10-year
periods,
in Florida, USA
Average number of Saltwater crocodile attacks per year for 10-year periods,
in Australia.
Saltwater crocodiles
were legally protected in Australia in 1971-74.
The most complete datasets are available for Saltwater crocodiles in Australia
and American alligators in Florida, USA (where >90% of attacks in the USA have
occurred). Notwithstanding changes in human population due to tourism and other
factors, the average number of attacks per year (2000-2007 period) relative to
the crocodilian and human populations suggest less interaction between people
and alligators. Due to the lower human population and longer periods of cooler
weather in Louisiana, there have been very few attacks there relative to the
heavily populated State of Florida. On the other hand, in the sparsely populated
Northern Territory and far north Queensland of Australia, the number of attacks
by Saltwater crocodiles has been relatively higher.
Parameter
American Alligator
Saltwater Crocodile
Florida
Louisiana
NT
FNQ
Attacks/year/100,000 crocodilians
0.71
<0.00
2.67
4.50
Attacks/year/100,000 people
0.06
<0.00
1.33
0.51
“Nuisance alligators” and “Problem Crocodiles”
Some sophisticated crocodilian management programs include mechanisms for
dealing with crocodilians that are considered a threat to people and/or
livestock.
In the Northern Territory of Australia some 220-240 “problem” Saltwater
crocodiles (0.5 to 4.6 m total length) are removed annually from Darwin Harbour
by wildlife rangers, to improve public safety. Crocodiles are captured live,
mostly in baited traps, and removed to crocodile farms to be used as raising or
breeding stock. A tendency for relocated individuals to return to their site of
capture means that relocation is not an effective management tool.
The Florida Wildlife Commission receives some 17,000 complaints each year about
“nuisance” American alligators. In 1987 a formal nuisance alligator program was
established, and more than 6000 are now captured and removed annually (around
91,000 nuisance alligators were harvested between 1977 and 2001). Private
trappers are used to perform this service - they are compensated for their time
and effort through the sale of skins and meat. A similar system operates in the
State of Louisiana.
Crocodilian Attack Database
A database on attacks by crocodilians on humans is maintained by Dr. Richard
Fergusson (CSG Regional Chairman for Africa). The collation and analysis of such
data will assist conservation and management efforts by allowing us to
understand the nature of attacks.
Recommended reading
Caldicott, D.G.E., Croser, D., Manolis, C., Webb, G. and Britton, A. (2005).
Crocodile attack in Australia. An analysis of its incidence, and review of the
pathology and management of crocodilian attacks in general. Wilderness and
Environmental Medicine 16(3): 143-159.
Conover, M.R. and Dubow, T.J. (1997). Alligator attacks on humans in the United
States. Herp. Rev. 28: 120-124.
Fergusson, R. (2004). Preliminary analysis of data in the African
human-crocodile conflict database. Crocodile Specialist Group Newsletter 23(4):
21.
Langley, R.L. (2005). Alligator attacks on humans in the United States.
Wilderness and Environmental Medicine 16(3): 119-124.
Additional reading
Behra, O. (1996). Reports of crocodiles attacks on people in Madagascar 1990 to
1996. Crocodile Specialist Group Newsletter 15(3): 3-4.
Bustard, H.R. and Singh, L.A.K. (1982). Gharial attacks on man. J. Bombay Nat.
Hist. Soc. 78: 610-611.
Edwards, H. (1998). Crocodile Attack in Australia. J.B. Books: Marleston,
Australia. Evans, P. and Wilkinson, P. (1997). Black Caiman attack. Crocodile Specialist
Group Newsletter 16(3): 5-6.
Finger, A.G., Rainwater, T.R., McMurry, S.T., Platt, S.G., Rosado, N., Windsor,
M. and Mazzotti, F.J. (2002). Human-crocodile conflict in Belize: a summary. Pp.
198-199 in Crocodiles: Proceedings of the 16th Working Meeting of the IUCN-SSC
Crocodile Specialist Group. IUCN: Gland, Switzerland.
Hall, P.M. (1991). Dangerous to man? A record of an attack by a Black Caiman in
Guyana. Herp. Rev. 22: 9-11.
Hines, T.C. and Keenlyne, K.D. (1977). Two incidents of alligator attacks on
humans in Florida. Copeia 1977(4): 735-738.
Huerta-Ortega S.M. and Ponce-Campos, P. (2002). Interaccion hombre-cocodrilo en
la costa de Jalisco, Mexico. Pp. 200-203 in Crocodiles: Proceedings of the 16th
Working Meeting of the IUCN-SSC Crocodile Specialist Group. IUCN: Gland,
Switzerland.
Kar, S.K. and Bustard, H.K. (1983). Saltwater crocodile attacks on man. Biol.
Cons. 25: 377-382.
Marlin, J.A., Marlin, K.K. and Platt, S.G. (1995). A documented case of an
attack by Morelet’s Crocodile (Crocodylus moreletii) on man. Bull. Chicago Herp.
Soc. 30: 165-167.
Platt, S.G., Ko, W.K., Kalyar Myo, M., Khaing, L.L. and Rainwater, T. (2001).
Man eating by estuarine crocodiles: the Ramree Island massacre revisited. Herp.
Bull. 75: 15-18.
Pooley, A.C., Hines, T. and Shields, J. (1989). Attacks on humans. Pp. 172-186
in Crocodiles and Alligators. Weldon Owen: New York.
Richardson, J. and Livingstone, D. (1962). An attack by a Nile crocodile on a
small boat. Copeia 1962(1): 201-204.
Ritchie, J. and Jong, J. (1993). Bujang Senang Terror of Batang Lupar. Samasa
Press: Kuching.
Steubing, R. (1983). Sarawak’s killer crocodiles. Malayan Naturalist 37: 17-23.
Steubing, R., Ismael, G. and Sallih, K. (1985). On the Possible Causes of
Crocodile Attacks in Batang Lupar, Sarawak. University of Malaysia Sabah Campus:
Kota Kinabalu.
Stringer, C. (1986). The Saga of Sweetheart. Adventure Publications: Darwin,
Australia.
Vyas, R. (1993). Recent cases of man-eating by the Mugger (Crocodylus palustris)
in Gujarat State. Hamadryad 18: 48-49.
Webb, G. and Manolis, C. (1989). Crocodiles of Australia. Reed Books: Sydney. Webb, G.J.W., Yerbury, M. and Onions, V. (1978). A record of a Crocodylus
porosus (Reptilia, Crocodylidae) attack. J. Herpetol. 12: 267-268.
The incidence of crocodilian attacks on humans in many countries is very
difficult to quantify. There is little doubt that many more people are attacked
than is reported, as many attacks occur in remote areas. Accurate data
collection does not usually occur until a species is legally protected and
formal monitoring is introduced. For example, in northern Australia, details of
Saltwater crocodile attacks prior to 1971 (when the species was protected) are
lacking, yet records after 1971 are detailed and complete. Interestingly, the
recent increases in reports of attacks by Saltwater crocodiles in Papua New
Guinea are thought to be in part due to better communication being available to
people living in remote areas - namely mobile telephones!
