Parental Infanticide: Children for Breakfast?

Eclectus parrots, Eclectus roratus, exhibit reverse sexual dichromatism which means that males and females differ in terms of colouration (see fig.1). In eclectus parrots, stark differences in colour of the beak and plumage are evident from as early as when they are nestlings. In fact it is interesting to note that till a few decades ago scientists believed that the two were different species altogether!

Male (left) and female (right) eclectus parrots perched on branch.

Fig 1: Male (left) and female (right) eclectus parrots perched on branch.

However, this reverse sexual dichromatism is not merely of aesthetic significance. The eclectus parrot is reknowned for being able to exercise extreme bias in sexual allocation. Hence, this is the reason why: “one eclectus in Chester Zoo produced 30 sons before the first daughter was produced” (Heinsohn et al., p. 1325). So what is the secret behind being able to maintain such a remarkable bias in sexual allocation?

Fig. 2: on day 3 this check is already clearly a male due to its yellow beak.

Heinsohn recognises the likelihood, yet until further study merely specualtion, of bias to occur at fertilization and probably, during ovulation (ibid., p. 1328). However, scientists also recognise that infanticide and cannibalism is likely because nestlings go missing and no remains are found. In addition, since eclectus parrots can be easily sexed after hatching, the parents job of sexing their children is made appraent at first sight. Therefore, eclectus parrots it is either ‘death or love at first sight’. Siblicide is common amongst birds when the youngest nestlings are pushed off the nest. However, parental infanticide is a less well known area of study which Heinsohn promises to look at in closer in detail in his studies to come.

Closer to home, more substantial evidence of parental infanticide and cannibalism can be found in the case of the Oriental Pied Hornbill, Anthracoceros albirostris, in Singapore (photgrpahic evidence is included). Afterall, one may have to conlcude that parental supervision may not always be the best thing for children!!!


R. Heinsohn, S. Legge & S. Barry, 1997. Extreme bias in sex allocation in Eclectus parrots. Proceedings of the Royal Society, Biological Sciences, 264: 1325-1329.

Ellegren H, Gustaffson L & Sheldon BC, 1996. Sex ratio adjustment in relation to paternal attractiveness in a wild bird population. Proceedings of National Academy of Science USA, 93(21):11723-11728.

Kevin J McGraw & Mary C Nogare, 2005. Distribution of unique red feather pigments in parrots. Biology Letters, 1, 38-43.

“Infanticide-cannibalismm in Oriental Pied Hornbill,” Prof Ng Soon Chye et al. Bird Ecology Study Group, 09 Apr. 2009. URL: http://besgroup.talfrynature,com/2009/04/09/infanticide-cannibalism-in- oriental-pied-hornbill/ (accessed: 9 Apr. 2010).

“Oriental Pied Hornbill: Parental infanticide,” Marc Cremades & Prof Ng Soon Chye. Bird Ecology Study Group, 07 Jun. 2007. URL: (accessed: 9 Apr. 2010).

Babies at Risk, Cannibalism in Polar Bears

Polar bear cannibalism

A male polar bear carries the head of a polar bear cub it killed and cannibalized in an area about 300 km (186 miles) north of the Canadian town of Churchill November 20, 2009. Climate change has turned some polar bears into cannibals as global warming melts their Arctic ice hunting grounds, reducing the polar bear population, according to a U.S.-led global scientific study on the impacts of climate change. Credit: REUTERS/Iain D. Williams

There has been recent coverage on cannibalistic behaviour of the polar bears (Ursus maritimus). On December 2009, it was reported in The Times that the climate change is ‘forcing polar bears to become cannibals’ ( According to climate change campaigners, the increasing cases of polar bear cannibalism is attributed to the melting of ice and slow ice formation, leading to a decrease in platform from which to hunt seals. However, Inuit leaders (indigenous people inhabiting the Arctic regions) has classified the polar bear cannibalism occurrence as normal.

This uncommon animal behaviour has been seen before and is not the first time being documented. As early as 1985, possible cannibalism by polar bears have been recorded. It is usually the adult male that kills the young while the female tries to defend them. It was found that cannibalism among polar bears does occur under natural conditions (Lunn & Stenhouse, 1985). The reason for such occurrences are still unknown but several reasons have been suggested to explain these actions.

The initial speculation was that the adult male killed young polar bears so that the mother will breed with him. However, the male showed no interest in the adult female after the event which led to the conclusion that the killing was simply for food. Interestingly, it has been observed that the polar bears who cannibalize do not appear to be malnourished. Subsequent studies believe that infanticide may be a density dependent parameter in polar bear populations. Infanticide may be a form of population control but it does not explain the need to cannibalize on the dead cubs. There are also suggestions that geographic features play a part (Derocher & Wiig, 1999).

The reasons stated do not provide a satisfactory answer to the cannibalistic behaviour of polar bears. Although it is a natural occurrence, the climate change in contemporary world cannot be completely ruled out. To better understand the complex interacting factors of such events, more direct observational data is needed (Dyck & Daley, 2002).

A male polar bear drags the remains of a polar bear cub it killed and cannibalized in an area about 300km (186 miles) north of the Canadian town of Churchill November 20, 2009.  Credit: REUTERS/Iain D. Williams

A male polar bear drags the remains of a polar bear cub it killed and cannibalized in an area about 300km (186 miles) north of the Canadian town of Churchill November 20, 2009. Credit: REUTERS/Iain D. Williams


Lunn, NJ & Stenhouse, GB. (1985). An observation of possible cannibalism by polar bears (Ursus maritimus). Canadian Journal of Zoology/Revue Canadienne de Zoologie [CAN. J. ZOOL.]. Vol. 63, no. 6, pp. 1516-1517.

Derocher, A.E & Wiig, Ø. (1999). Infanticide and Cannibalism of Juvenile Polar Bears (Ursus maritimus) in Svalbard. ARCTIC Vol. 52, No. 3 P. 307–310

Dyck, M.G & Daley, K.J. (2002). Cannibalism of a Yearling Polar Bear (Ursus maritimus) at Churchill, Canada. ARCTIC Vol. 55, No. 2 P. 190–192