One Environment, Two contrasting rearing practises.

Somehow, as I was thinking about this blog post, penguins crept into my mind. Perhaps it was because of the disney cartoons that have unknowingly influenced me. The penguin video I found in Youtube focuses on King Penguins and hence the topic.

King Penguins

You can view the video at:

According to the video filmed by BBC, There are around 2 million pairs King Penguins in the Antartica. They also have a colony actually had 600,000 chicks together while their parents hunt for food. King penguins eat small fish, mainly lanternfish, and squid and rely less than most Southern Ocean predators on krill and other crustaceans.

On foraging trips they repeatedly dive to over 100m (350 feet), often over 200m(700 feet). Thus the King Penguin dives far deeper than any other penguin, notably excluding their closest relative, the larger Emperor Penguin. Hence, while parents go on their foraging trips, the chicks are often left alone and are fed around once every week.

However, not all parents make it back to feed their chicks because of seal attacks. As weather changes along with global warming, seals started developing an appetite for penguins. For those adult parent who did manage to make it back to the colony. They will have to spend a few hours looking for their chicks (imagine that there’re 600,000 chicks together, not to mention that they look alike!)

The amazing thing is, parents are still able to find their chicks because they can recognize each other’s voices. While in search for their chicks, the parent would call out to them and if it is the voice that his/her parent, the chick would response by twittering back. Then, once the child is found, as though to confirm that the chick is indeed its own, the parent would walk through a distance with the chick and then finally feed it. Parents have to take care of their chicks for slightly more than a year, meaning these chicks have to rely on their parents until they can start foraging food for themselves.

Dutiful Mothers taking care of their cubs until they're strong enough to survive.

Unlike their neighbor polar bears, where the females take care of the cubs, and the males being likely to kill their own cubs; both penguin parent help to take care of the chick. Polar bear mothers usually are fiercely protective of their cubs, while the penguins leave their cubs alone for weeks during foraging. They would take care of their cubs for around 28 months to learn the skills needed to survive in the North. Both animals are similar in a way that they take a relatively long period in rearing their young. Perhaps, this is attributed to the harsh condition that they are living in.

“King Penguin (Aptenodytes Paragonicus)”, British Broadcasting Corporation, accessed on 7th April, 2010:

“Polar Bear”, Ursus Maritimus, National Geographic, accessed on 7th April 2010:

“King Penguins Declining Due to Global Warming”, Matt Kaplan, National Geographic News, February 11, 2008, Accessed on 7th April 2010:

Kid: “I don’t look anything like my mom!” — Crossbreed Adoption: A Challenge to Darwinian Theory

Maternal Instinct Cross the Species Line

Cross species adoption is a phenomenon that has been puzzling scientists for years. Such behaviour contradicts Darwinian Theory of Natural Selection and Evolution, which is the selection of behavioural traits that increases the rate of survival and reproduction. Adopting someone else’s young that holds no similar traits and investing precious resources and energy in ensuring their survival not only reduces the mother’s reproductive success, but also the species’ own rate of survival. The Darwinian Theory fails to explain this phenomenon, that happens (as seen in video) not only between cats and dogs, but across all types of species, such as a baby chimpanzee being nursed by a leopard who preyed on its mother, and a young deer nursed by a feline cat.

Dog adopts a litter of kittens

The title of the video is called “Maternal Instincts crosses the Species Line”. But instincts is categorized under learning, which is also under natural selection, again, the Darwinian Theory. So we then start to question, if natural selection ultimately aims to bolster the rate of survival and reproduction, and if cross breed adoption is proven to challenge that idea, then can we truly say that cross breed adoption is a result of strong maternal instincts?

It could be possible. In the National Wildlife Magazine’s “Parenting Paradox”, written by Sharon Levy, it mentioned that such a behaviour may be advantageous in terms of gaining parenting experience. Moreover, the research article “Cross-Genus Adoption by Wild Capuchins” mentioned Maestripieri’s (2001) suggestion that the “adoption of an unrelated infant is an evolutionary maladaptive consequence of mechanisms selected to promote mother-infant bonding”. This article can be found at:,%20692%20-%20700%202006.pdf.

But then again, these are all human interpretations of what we observe. Whether they truly represent the meanings of such behaviour, we can never be sure.


Cross-Genus Adoption of a Marmoset (Callithrix jacchus)
by Wild Capuchin Monkeys (Cebus libidinosus):
Case Report Patricia Izar, Michele P. Verderane, Elisabetta Visalberghi, Eduargo B. Ottoni, Marino Gomes De Oliveira, Jeanne Shirley and Dorothy Fragaszy.

Patricia Izar,  Michele P. Verderane,Elisabetta Visalberghi, Eduardo B. Ottoni, Marino Gomes De Oliveira, Jeanne Shirley & Dorothy Fragaszy, 2006. Cross-Genus Adoption of a Marmoset (Callithrix jacchus) by Wild Capuchin Monkeys (Cebus libidinosus): Case Report. American Journal of Primatology, 68:692–700.

“Parenting Behaviour,” by Sharon Levy. National Wildlife Magazine, Aug/Sept 2002. URL: (assessed on 5 April 2010).

“Maternal Instinct Crosses the Species Line,” by CBS News Youtube Channel, 22 April 2009. URL: (assessed on 6 April 2010).