Fairness? Does It Exist?

Food for thought

“You and your friend are locked in cell separated by a see through thin wall with a small opening.

You have the tool but can’t reach the nuts that are sealed in a container that is placed in your friend’s cell.

Though your friend has the nuts but he needs the tool to reach the nut! So what will you do?”


Tufted Capuchin by Frans de Waal. Powell K: Economy of the Mind. PLoS Biol 1/3/2003: e77. URL: http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0000077 (accessed on 1 April 2010)

How do you think this pair of Tufted Capuchin (Cebus apella) would react in the same scenario? Let’s take a look!

The Tufted Capuchin (Cebus apella) is a New World primate commonly found in South and Latin America. They have the largest brain relatively to their size among all the other species of monkey. This gives them the intelligences, unheard of in the wild. The Tufted Capuchin is an omnivorous animal feeding mainly on fruits, nuts, insects and small vertebrates. They are well known for astonishing problem solving abilities to help them forage for food.

In the experiment, they cooperated  and later share the reward equally! Besides showing mathematical ability, they also displayed reciprocal altruism and fairness. The idea of fairness is further illustrated in the second part of the experiment where the monkey would rather go hungry than to accept less than equal treatment.

Besides Tufted Capuchin, there are other groups of animals that have displaced sense of fairness. Some examples include wolves, coyotes, elephants, rodents, bats and whales. If you are interested in the detailed write up for the examples, you can visit http://www.telegraph.co.uk/earth/wildlife/5373379/Animals-can-tell-right-from-wrong.html.

Essentially, scientists studying animal behavior believe that besides humans, animals are capable of showing complex emotions and have a sense of morality which help them to live in groups. Interestingly, it do tell us something about the evolution of fairness in humans. It seems to suggest that the sense of fairness is deeply embedded in human evolutionary history rather than a social trait learned from other humans. On a side note, in a study, statistics have shown that market integration, participation in religion and community size affect human’s sense of fairness. Perhaps, it is a combination of both? Maybe we are born with the sense of fairness, however, we are not aware of it until someone else comes “knocking at our door” to enlighten us.


1. “Animals can tell right from wrong,” by Richard Gray. Telegraph UK. 23 May 2009. URL: http://www.telegraph.co.uk/earth/wildlife/5373379/Animals-can-tell-right-from-wrong.html (access on 1 Apr 2010).

2. Henrich, J., Ensminger, J., McElreath, R., Barr, A., Barrett, C., Bolyanatz, A., Cardenas, J. C., Gurven, M., Gwako,        E., Henrich, N., Lesorogol, C., Marlowe, F., Tracer, D., & Ziker, J. (n.d.). Market, religion, community size and the evolution of fairness and punishment.Unpublished manuscript, Vancouver. pp1-6

3. “Monkeys Show Sense Of Fairness, Study Says,” by Sean Markey. National Geographic News, 17 September 2003. URL: http://www.primates.com/monkeys/fairness.html (access on 1 Apr 2010).

4. “Sense of fairness goes back to the monkeys,” by Jeanna Bryner. msnbc, 13 nov 2007. URL: http://www.msnbc.msn.com/id/21773403/ns/technology_and_science-science/ (accessed on 1 Apr 2010).

5. Y. Hattori, H. Kuroshima and K. Fujita, Cooperative problem solving by tufted capuchin monkeys (Cebus apella): Spontaneous division of labor, communication, and reciprocal altruism, J. Comp. Psychol. 119 (2005), pp. 335–342.

The lesbian Laysan albatross?

A female-female pair of Laysan albatross. Photo by Eric A. Vanderwerf.

A female-female pair of Laysan albatross at Kaean Point, Hawaii. Photo by Eric A. Vanderwerf.

The Laysan albatross (Diomedea immutablis) is known for its monogamous nature. The female and male birds mate with the same partner once a year for their whole lives. In 2008, however, biologist Lindsay C. Young discovered that their lifelong partners need not necessarily be of the opposite gender. She found that out of 125 Laysan albatross nests in Kaena Point, Hawaii, 31% were attended to by female-female couplings (Young, Zaun, and VanderWerf 323). The figure is “more than double the highest proportion of female-female pairing previously known in any animal,” making this a landmark case in the study of homosexual behaviour in animals (Ibid., 324).

These same-sex pairs of Laysan albatross do not copulate with one another–either female mates with a male, sometimes through “soliciting” for sex–but the female afterwards returns to lay its egg in a nest it shares with its female partner (“Can Animals Be Gay?”). There, the couple incubates their egg collaboratively, alternating in turns like a female-male couple. Sometimes, both females lay an egg, resulting in what is called “supernormal clutch,” when the Laysan albatross’s clutch size of 1 egg per nest is exceeded. In fact, this occurred to 44% of the female-female pairs Young studied (Young, Zaun, and VanderWerf 323). In such cases, the pair members incubate only one of the two eggs.

Young accounts for this phenomenon of same-sex pairings on the basis of the female-biased sex ratio at her study location. As a result of female-dominated migration, 59% of Laysan albatross at Kaena Point were female, resulting in a shortfall in mates for them (Ibid., 324). This spur towards homosexual behaviour due to a lack in one sex is sometimes called “the prisoner effect” (“Can Animals Be Gay?”). Two other biologists, Marlene Zuk and Nathan W. Bailey, build upon Young’s reasoning to assert that we can see animal homosexuality as an evolutionary by-product. Zuk and Bailey assert that the Laysan albatross’s behaviour represents an “alternative reproductive strateg[y],” where given the dearth of male mates, “the females were able to avoid complete loss of reproductive success by joining forces another female” (658). It remains to be seen if the reasoning behind such “adaptive” behaviour can equally apply to the male Laysan albatross, or to other animals too (659).


One female Laysan albatross grooming another. Photo by Alex Wegmann.


“Albatross Couple,” by Alex Wegmann. LiveScience. URL: http://www.livescience.com/php/multimedia/imagedisplay/img_display.php?s=animals&c=&l=on&pic=080527-albatross-couple-02.jpg&cap=Paired+female+Laysan+Albatrosses+grooming+each+other.+Credit%3A+Lindsay+Young.&title (accessed on 6 Apr 2010).

“Can Animals Be Gay?,” by Jon Mooallem. The New York Times, 29 Mar 2010. URL: http://www.nytimes.com/2010/04/04/magazine/04animals-t.html?hpw=&pagewanted=all (accessed on 6 Apr 2010).

“Same Sex Animals,” by Eric A. VanderWerf. LiveScience. URL: http://www.livescience.com/php/multimedia/imagedisplay/img_display.php?s=animals&c=rbritt-columnist-153×65&l=on&pic=090616-same-sex-animals-02.jpg&cap=This+photo+shows+a+female-female+pair+of+Laysan+Albatross.+Females+cooperatively+build+nests+and+rear+you (accessed on 6 Apr 2010).

Young, Lindsay C., Zaun, Brenda J., and VanderWerf, Eric A., 2008. Successful same-sex pairing in Laysan albatross. Biology Letters, 4(4): 323-5.

Zuk, Marlene and Bailey, Nathan W., 2008. Birds gone wild: same-sex parenting in albatross. Trends in Ecology and Evolution, 23(12): 658-60.

The Importance of Being Honest: The Sea Cucumber Spills All

Sea Cucumbers make up 90% of the biomass on deep sea floors

Sea Cucumbers make up 90% of the biomass on deep sea floors

You have heard the proverb, honesty is the best policy. These wise words seem to extend to the animal kingdom as well, as the sea cucumber’s behaviour demonstrates: for the sea cucumber, spilling its guts – pun intended – can save its life.

Sea cucumbers are marine animals that belong to Phylum Echinodermata and are of the class Holothuirodea. Now, appearances are deceiving. The cooked sea cucumber you usually encounter may appear monumentally boring but it has a quirky natural defence that will either enthral you or make you retch in response.

Here’s a video of an intentionally provoked sea cucumber, with a background commentary that does not reflect the most brilliant of humans:
(please do not provoke sea cucumbers in real life just to watch them vomit)


When threatened, most species of sea cucumbers may expel all or parts of their internal organs through the mouth or anus, in order to distract or scare their predator away. For some species, toxins may also be released during this process of evisceration. Some sea cucumbers may expel sticky toxic strings called Cuvieran tubules which either poison the predator or immobilise it, giving the sea cucumber ample time to escape. Like its relative, the starfish, sea cucumbers can regenerate their internal organs over one to five weeks.  

Besides being the Claire Bennets of the Sea, sea cucumbers play a significantly fundamental role in deep sea ecosystems. Their diet of detritus contributes to nutrient recycling and their larvae are part of the plankton-based food chains. However, sea cucumbers, especially the edible ones, are at risk of being overharvested. In addition, land reclamation leading to habitat loss also threatens the survival of these animals. Without sea cucumbers, ecological systems will be upset and our very own survival placed at stake.

Therefore, save the sea cucumber, save the world.


VandenSpiegel, D., M. Jangoux & P. Flammang, 2000. Maintaining the line of defense: regeneration of Cuvierian tubules in the sea cucumber Holothuria forskali (Echinodermata, Holothuroidea). The Biological Bulletin, 198 (1): 34-49.

“Shedding New light on the Humble Sea Cucumber,” by N. Alcock. Aquatic Biodiversity & Biosecurity Update, 2003. Hosted on National Insitute of Water & Atmospheric Research:  http://www.niwa.co.nz/news-and-publications/publications/all/abb/2003-03/cucumber (accessed on 6 April 2010).

“Sea cucumbers (Holothuroidea) on the Shores of Singapore,” by Ria Tan. WildFactSheets, December 2008.  Hosted on WildSingapore: http://www.wildsingapore.com/wildfacts/echinodermata/holothuroidea/holothuroidea.htm (accessed on 6 April 2010).

“Sea cucumber spills its guts,” by danyoferit. Youtube Channel, 29 December 2008. URL: http://www.youtube.com/watch?v=Ux6XiMAebn8&feature=related (accessed on 6 April 2010).

“Sea cucumber,” by Jack Jackson. National Geographic: Sea Cucumbers. URL:  http://animals.nationalgeographic.com/animals/invertebrates/sea-cucumber (accessed on 6 April 2010).