Don’t eat me, Dad!

Be glad that you are alive and your parents love you, because some other parents don’t. They eat their babies instead. It seems like fathers in male pregnancies may be more inclined to eat their babies if their mothers are ugly. A case in point is the Gulf pipefish (Syngnathus scovelli).

Found in seagrass beds and other densely vegetated shallow grounds, the Gulf Pipefish is a freshwater fish that lives as long as three years, and is the only known species among 24 North American pipefish that enters freshwaters. Seahorse clings to pipefishCharacteristic of the pipefish is the slim body, a snout, and usually only dorsal fins for movement, making it look almost a swimming pencil that bends at the end. Male pregnancy amongst the Gulf pipefish means that fertilization only happens after the female deposits her eggs in the male’s brood pouch. The father then nurtures the embryos in his brood pouch until parturition.

It seems like female beauty in the eyes of Gulf pipefish is size. Smaller females (93-106mm) were consistently discriminated against in favor of larger ones (108-122mm) in a 2010 study by Texas A&M. The study suggests that bigger mothers transfer more eggs each copulation, and more of their babies are stronger and develop fully into parturition. Since males cannot alter their level of investment in a brood, eggs from larger mothers seem to be a more resource-efficient way of parenting.

The sex ratio amongst Gulf pipefish favors females in reproduction, so what happens when a male has already mated with a smaller, thus less attractive, female? He can reduce nutrient flow to the brood to mediate this energetically costly pregnancy, so that siblings compete for survival. This isolation is not so much passive as it is cannibalistic – Sagebakken et. al’s recent study in a similar species found that the father can absorb embryonic nutrients through the brood pouch to his liver and muscle tissue.

Infant-eating amongst animals remains much a controversy. This hypothesis that fathers kill in order to preserve his resources for the next pregnancy in hope of increasing net reproductivity has been criticized by Klug, Lindström, and Mary for being applicable to only some species. After all, it is possible that Daddy kills some babies to modulate their siblings’ competition for resources.

References

Klug, Hope, Kai L Lindström & Colette M. St. Mary, 2006. Parents Benefit from Eating Offspring: Density-dependent Egg Survivorship Compensates for Filial Cannibalism. Evolution 60(10): 2087-2095.

“Male Pregnancy: The Dark Side,” by Nature. Scientific American, March 17, 2010. URL: http://www.scientificamerican.com/blog/post.cfm?id=pregnant-male-fish-can-choose-to-ma-2010-03-17 (accessed April 8, 2010).

Paczolt, Kimberley A. & Adam G. Jones. Post-copulatory sexual selection and sexual conflict in the evolution of male pregnancy. Nature 464: 401-404.

Sagebakkne, Gry, Ingrid Ahnesjö, Kenyon B. Mobley, Inês Braga Gonçalves & Charlotta Kvarnemo, 2010. Brooding fathers, not siblings, take up nutrients from embryos. Proc. R. Soc. B 277: 971-977.

Syngnathus scovelli.” Smithsonian Marine Station at Fort Pierce. URL: http://www.sms.si.edu/IRLspec/Syngna_scovel.htm (accessed on April 9, 2010).

We don’t just mate. We are earthquake indicators too.

The next time you take a walk in San Ruffino Lake, Central Italy, and saw toads around, relax, enjoy the beautiful scenery and be rest assured that you won’t experience any earthquake while you are there.

Dr Rachel Grant of the Open University in UK was carrying out a daily observational study on the behavior of common toads, Bufo Bufo, in San Ruffino Lake, a common breeding site for them, when she observed unusual toad breeding behaviors. This happened around the time when an earthquake struck L’Aquila, Italy, in 2009. There were no clues as to how the toads sensed the impending earthquake but the population declined by 96% in the breeding site 5 days before the earthquake occurred. The lake is situated 74.29 Km away from the earthquake epicentre.

spawningBufo Bufo is usually found on land and, only during their breeding season, in water bodies such as ponds and lakes. There are usually more males than females in the breeding sites and competition to pair with females occur. Males will grab the opportunity to cling on to the back of a female that is heading towards the breeding site (as can be seen from the 1st picture). Those who fail to find an available female will attempt to displace the attached male (shown in the 2nd picture).
FIGHT!!

The successful pair will proceed to the spawning sites where spawning occurs. The males usually hang around after his first spawn and attempt to carry out subsequent mating with another female during the entire breeding season. The success rate is usually very low due to the competition for females.

View normal Bufo Bufo spawning behaviour here.

What was unusual for the toads in San Ruffino Lake was that it was in the midst of the spawning period and the number of breeding pairs suddenly dropped to zero 3 days before the earthquake. There were very little breeding pairs from the period of the earthquake to the last aftershock. Fresh spawns were only observed 6 days before the earthquake and 6 days after the last aftershock. No fresh spawn were observed in the period before the last aftershock, meaning that no breeding took place at all.

The most probable reason for the decline in population was that the toads were fleeing to higher grounds for safety, to prevent themselves from being killed by falling objects. There were various speculations about how the toads detect the impending disaster but there are no existing concrete evidence for support.

This amazing observation which happened to take place during the period of a natural disaster shows us how intricately life is linked to the environment. Having this knowledge at the back of our minds, keep a look out for toads in spring, if you happened to be in Europe, and be thankful to have this natural earthquake indicator around you.

References:

To-be-published journal:
“Predicting the unpredictable; evidence of pre-seismic anticipatory behaviour in the common toad,” by R. A. Grant & T. Halliday. The Zoological Society of London, 31 Mar 2010. URL: http://www3.interscience.wiley.com/journal/123337858/abstract

Journal:
N. B. Davies & T. R. Halliday, 1979. Competitive Mate Searching in Male Common Toads, Bufo Bufo. Animal Behaviour, 27, 1253-1267.

Article:
Toads can ‘predict earthquakes’ and seismic activity, by Matt Walker. BBC News, 31st March 2010. URL: http://news.bbc.co.uk/earth/hi/earth_news/newsid_8593000/8593396.stm (accessed on 5th April 2010).

Photographs:
“Mating Toads” by nutmeg66. Flicker, 25th March 2009. URL: http://www.flickr.com/photos/rachel_s/3385386089/ (accessed on 8th April 2010).

“Common toads (Bufo bufo) in amplexus” by nutmeg66. Flicker, 25th March 2009. URL: http://www.flickr.com/photos/rachel_s/3385386087/ (accessed on 8th April 2010).

Video:
“Common Toads in their spawning lake” by slaphed. YouTube videos, 25th March 2010. URL: http://www.youtube.com/watch?v=rlNz87LTj4s

Till death brings us closer.

It was a lazy afternoon on 5 June 1995. Kees Moliker was settling into his chair, minding his own business when he heard a loud thud outside his window. An ornithologist by training, his office was situated within the Natuurmuseum Rotterdam in Nethlerlands. Cautiously he approached the window where the thud was heard and he witnessed a horrifying sight! An adult male mallard was lying dead on the ground. There was another mallard mounting the corpse and raping it. Moliker stared transfixed at the sight before him…for nearly 75 minutes. When he couldn’t stand it anymore, he left his office and approached the crime scene to stop the hideous crime from continuing.

Scene of Crime

Scene of Crime

What just happened? Sex with a corpse? How is that possible? Contrary to what many people believe about animal sexual behavior, there are species whose sexual behavior are promiscuous and opportunistic in nature. A wide range of animals appear to masturbate and use objects as tools to help them do so. In many species it seems that animals try to give and receive sexual stimulation where procreation is not the aim.

gay mallards

On that fateful day in June 1995, Kees Moliker witnessed animal homosexual necrophilia. Necrophilia in animals is essentially when a living animal engages in a sexual act with a dead animal. What happened on that day was when a drake mallad (Anas platyrhynchos) was in full flight, it hit the glass facade of the Natuurmuseum Rotterdam building and died 2 metres away from the facade. According to Moliker, he speculated that the 2 mallards were involved in some kind of aerial chase or pursuit flight and while the victim flew into the glass building, the drake that was pursuing managed to avoid collision and landed next to the dead mallard. This is a common motif in duck behavior which is also known as rape flight. It was unlikely that the other drake was just passing by and saw the dead mallard as it appeared beside the corpse in less than a minute after the mallard’s death.

mallard

After landing, the “rapist” forcibily picked into the back, the base of the bill and mostly into the back of the head of the dead mallard for about two minutes, then mounted the corpse and started to copulate, with great force,
almost continuously picking the side of the head. The necrophilic rapist only reluctantly left his victim when Moliker approached the dead mallard and “rescued” it from the “rapist” after 75 minutes. So it seemed that it could have gone on even longer if Moliker hadn’t intervened.

Upon inspection of the dead mallard, it was revealed that it was a male mallard. This was unusual as necrophilia was known in the mallards but only among heterosexuals. Essentially, this made the first observed case of homosexual necrophilia in mallads. This discovery netted Moliker an Ig nobel prize in biology awarded for improbable research; research that “first make people laugh, and then make them think.”

You can check out the video Homosexual Necrophilia

Now a few questions that deserve further research are these. Did the gay duck just broke up with his partner? And is he doing this to vent his frustration? Well, these are interesting things to contemplate on.

References

Moeliker.C.W., 2001. The first case of homosexual necrophilia in the mallard Anas platyrhynchos (Aves: Anatidae). DEINSEA, 8: 243-247.

“Necrophilia among ducks ruffles research feathers” by Donald.Macleod. Improbable Research, 8 March 2005. URL: http://www.guardian.co.uk/education/2005/mar/08/highereducation.research (accessed on 8 Apr 2010).

Minimovies-Ig Nobel  Prizes Episode 1/6. (Homosexual necrophilia in the mallard duck), 2 October 2009. URL: http://www.youtube.com/watch?v=NfWiqdlmsm4 (accessed on 8 Apr 2010).


MULTIPLE SEX PARTNERS??

Deep sea anglerfish, Melanocetus Johnsoni, are found in the most inhospitable place on the planet; the cold, dark bottom of the sea. There are over 200 species of Anglerfish, each differing in terms of body structures and size.


However, their most common and distinctive feature is a slender, antenna-like projection extending from its head or mouth, known as a dorsal spine. The spine supports a light-producing organ called a photophore, which acts like a “fishing-rod” as prey are attracted to the luminescent bubble.


Here are some examples of the various species of Anglerfish

http://tolweb.org/Ceratioidei/22000/2007.10.02#AboutThisPage



However, what is most interesting about deep sea Anglerfish is not just their grotesque appearance and their preying manner, but even more so their mating behavior. The role of males in deep sea Anglerfish is completely reduced. Being barely 1/10th of the size of a female, the male anglerfish live as parasites on females.



A female Anglerfish

SeaDevil


From the moment of birth, male anglerfishes seem to have no other role than to search out a female. The tiny male has no bioluminescent lure, instead, they have larger eyes presumably for spotting the flashing lure of the female and a greater olfactory organ (organ of smell, or nose) above its eyes.  The reasons behind these physical differences between the sexes could be because in the vast ocean, sexual pheromones are highly essential in locating a mate. Thus, in the dark and vast ocean, heightened sensitivity to the female pheromones is crucial in the reproductive lifestyle of the Anglerfishes.



The Male Anglerfish

Male Angler fish

Upon locating a female anglerfish, the puny male attaches itself to her body by biting into her. His teeth and jaw then recedes and a chemical is released which fuses the skin and blood systems of both parties. Thereafter, it becomes entirely dependent on the female for its nutrients and oxygen, similar to that of a parasite. In time, the male anglerfish’s eyes and other digestive organs regresses and its body degenerates into essentially a pair of sperm producing testicles.


At this juncture, the female essentially becomes a hermaphrodite, with up to 6 of these male parasites attached to various parts of her body. As a functional hermaphrodite, the female is able to have fertilize her eggs from the moment she releases them from her body.


example of female Anglerfish with attached male parasitesattached males

However this is not all, even more intriguing in fact is that the female anglerfish can carry as many as 6 of these parasitic males  at one time! thus a single female could have six pairs of testicles at her beck and call, supplying her with a fresh supply of sperms at any point in time!


Here is a video of the strange mating behavior of deep sea anglerfish

Angler fish mating customs


References:

Perun, Blane. (1999) “Deep Sea Angler Fish”

http://www.thesea.org/TheSea/deep_sea_angler_fish.html

Nationalgeographic.com (1996-2010) “Anglerfish”

http://animals.nationalgeographic.com/animals/fish/anglerfish/

“Angler Fish Mating Customs” by howtofaint. Youtube Channel, 7 april 2009

URL: http://www.youtube.com/watch?v=Lsmxs0uDXMo


Courtship in Birds; Same Old Song and Dance?

  “Everyone likes birds,” Sir David Attenborough.

Wilson's Bird Of Paradise

The birds-of-paradise, (Paradisaeidae), are pretty close to our shores. These colorful little birds (especially the males with their long plumes) are actually found in rainforests in surrounding islands of Indonesia and New Guinea.

Perhaps, even closer to home, is how close their mating behavior is to the courtship behavior in human beings.

The Birds-of-Paradise have developed a social mating system based on arenas or leks. Essentially, this is a stage that is cleared for the male to do his song and dance; a highly elaborate courtship display that features the magnificent plumage.

Wilson’s Bird of Paradise’s elaborate courtship ritual

The star of the video above is actually of the species of the Paradisaeidae, the Wilson’s Bird of Paradise (Cincinnurus respublica). He starts by actually clearing the arena, of twigs and leaves. This allows his magnificent color coat of feathers and unusually long plumes to be more visible to the potential female mate. At one point of time, it even displays its distinctive breast shield.

The video below features another, not so magnificently colored male species of the Paradisaeidae, using a similar stage or arena, for courtship behavior. Similarly after clearing away leaves and twigs, the stage is set for the male to put on his phenomenal dance show. Taking the ritual very seriously, he evens warms up before beginnings his elaborate display as this may last up to a few hours!

Beautiful Plumed Bird of Paradise

Studies have also shown that there is a strong correlation between achieving female preference if they were more conspicuous as possibly indicates a higher survival and fecundity for the female.

Interestingly, these elaborate displays seems to be learned behavior as the younger males stay on the fringes of the arena to practice clumsily before the star of the show takes over in the centre stage.

Does this parallel post modern society’s courtship rituals? Sir David Attenborough would probably beg to differ:

“These birds are so romantic and they have legends surrounding them. They all do the most extraordinary things, each with its individual dance and display.”

Beautiful Plumed Bird of Paradise's Dancing Ritual

Works Cited

Research Articles:

Davies, G. H. (n.d.). Meet Sir David. Retrieved March 31, 2010, from The Life Of Birds: http://www.pbs.org/lifeofbirds/sirdavid/index.html

Irestedt, M., Jonsson, K. A., Fjeldsa, J., Christidis, L., & Ericson, P. G. (2009). An unexpectedly long history of sexual selection in birds-of-paradise. BMC Evolutionary Biology .

Kirkpatrick, M., & Ryan, M. J. (1991). The evolution of mating preferences and the paradox of the lek. Nature , 33-38.

Videos:

BBC Wildlife. (2007, June 12). David Attenborough finds the rare exotic Wilson’s bird of paradise. Retrieved April 07, 2010, from YouTube: http://www.youtube.com/watch?v=fmmp3wrf9gg&feature=channel

BBC Wildlife. (2007, June 12). David Attenborough finds the rare exotic Wilson’s bird of paradise. Retrieved April 03, 2010, from YouTube: http://www.youtube.com/watch?v=fmmp3wrf9gg&feature=channel

Pictures Taken From:

Kirby, R. (2003). Wilson’s bird-of-paradise. Retrieved April 01, 2010, from Arkive: Images of Life on Earth: http://www.arkive.org/wilsons-bird-of-paradise/cicinnurus-respublica/image-G51010.html

Horseshoe Crabs Mating

Horseshoe crab mating on YouTube

Horseshoe crabs often referred to as a living fossil, is one of the most interesting creatures on earth because it’s origins dates back to millions of years ago. The video shows an interesting shot of the mating behaviour of the horseshoe crabs.

Background information of Atlantic Horseshoe Crabs

The horseshoe crab or Atlantic horseshoe crab, Limulus polyphemus is found along the eastern coast of North and Central America. It belongs to the Limulidae family which consists of three other species. It is a misconception that horseshoe crabs are crabs. In fact, they belong to the phylum of Arthropods, which consists of animals having an articulated body and limbs (The Horseshoe Crabs). Horseshoe crabs are now considered endangered animals due to the loss of habitats.

Mating behaviour

The female Limulus give off chemical attractants called pheromones, which the males can detect (The Horseshoe Crab). Once the male Limulus detects a female offshore, he grasps her with his specially modified claws, and the attached couple crawls toward the high tide line. Once copulation is over, the female, with the male still attached, digs into the sand and lays thousands of eggs which the male fertilizes externally (Rudloe, 1980). It was found that some male Limulus remain attached to the females for as long as 2 weeks!

Horseshoe Crabs mating

Horseshoe Crabs mating

However, there is strong competition between males for females because it was found that females tend to reach sexual maturity later and they return to the nest less frequently than males (Rudloe, 1980). Because of this, there is a difference in ratio between the males and females therefore leading to an intense competition for females as seen in the video. Even if a male is attached to a female, other satellite males will still “join in” to mate with the female by pushing away the current attached male.

References

H. Jane Brockmann. Mating Behavior of Horseshoe Crabs, Limulus polyphemus. Behaviour, Vol. 114, No. 1/4 :pp. 206-220.

“Horseshoe crab mating,” by solatia. YouTube Channel, 3 April 2007. URL: http://www.youtube.com/watch?v=MrrYtOc6Y0c (assessed on 4 March 2010)

Natural History:Spawning Behaviour. URL:http://www.horseshoecrab.org/nh/spawn.html (assessed on 4 March 2010)

Rudloe, A.E. 1980. The breeding behavior and patterns of movement of horseshoe crabs, Limulus polyphemus, in the vicinity of breeding beaches in Apalachee Bay, Florida. Estuaries 3, p. 177-183.

“Transvestite” Cuttlefish

Ever heard of a non-human example of a “Transsexual”? The Australian giant male cuttlefish, Sepia apama, entices many with its superb mimicry skills to disguise as a female cuttlefish in order to increase its chance in mating with the female cuttlefish.

Dressing up as girls?

Source: BBC NEWS- Dressing up as girls?

But why? The ratio of male to female cuttlefishes is four to one, females reject almost 70% of mating attempts, this creates fierce competition among the males. Thus, smaller size males have very slim chances to mate with females when compared to the bigger and more dominant-like male (Hanlon et al., 2005).

How? The Alternate mating strategy- “Visual deception is achieved when small males suddenly hide their sexually dimorphic fourth arms, acquire the mottled skin patterning typical of females, and shape their arms to mimic the posture of egg-laying females, who are not receptive to mating” (Hanlon et al., 2005). As many large males will be busy combating other large males and would not take these “transvestite” cuttlefish as a threat, these smaller males then take the chance to move near the female and attempt to make with it.

Success rate? Studies have shown that these female mimickers were able to escape the larger males through deception and position near the female in 30 out of 62 attempts, some large males also tried to mate with the mimickers (Hanlon et al., 2005). When mating with females, some mimickers show male displays of banners and moving stripes while some remained as the disguised female. Returning large males, which were involved in conflicts, tried to aggressively separate the mating pair (mimicker and female) or ignore the pair when they spot them. Females therefore may be subsequently fertilized by both the large males and the mimickers (Norman et al., 1999).

Second source which supports the above:

Norman, M.D., Finn, J., & Tregenza. T. (1999). Female Impersonation as an Alternative Reproductive Strategy in Giant Cuttlefish. Biological Sciences, 266 (1426): 1347-1349.

References:

Hanlon, R.T., Naud, M., Shaw, P.W., & Havenhand, J.N. (2005). Transient sexual mimicry leads to fertilization. Nature, 433: 212.

“Cuttlefish wimps ‘dress as girls,'” by unknown. BBC News, 19 Jan 2005. URL: http://news.bbc.co.uk/2/hi/science/nature/4188495.stm (accessed on 6 April 2010).

“Mating trick,” by Sciencentral. Sciencentral YouTube Channel, 11 Feb 2009. URL: http://www.youtube.com/watch?v=OEqsgwyvtqc (accessed on 6 April 2010).


Spit Swapping!

Why do humans kiss? If one really thinks about it, kissing is a pretty bizarre and gross action! Just as how it is sometimes described in narratives, kissing involves some heavy spit swapping and it is estimated that “hundreds or even millions of bacterial colonies move from one mouth to anther during a kiss.”

Most people if asked such a question, would probable answer that humans (Homo sapiens) kiss simply because it feels good. Well, yes, it does but scientists (philimatologists) who study the evolutionary history of kissing will probably not be satisfied with just that answer. Thus far, while there has been no conclusive reason as to why people perform this act of saliva trading, it is believed that kissing is a behavior that is both instinctive and learned.

Tigers kissing

For those who deem kissing to be part of our nature, other animals have been cited in support of this behavior. One of the most concrete proofs is from that of the Bonobos ape, the most human-like of all apes, which have been observed to kiss each other to offer comfort, to make up after fights and sometimes, for no seemingly special reason at all.

Then there are others who support the idea that kissing is learned rather than instinctual because it is a fact that not all human beings actually engage in acts of kissing – certain tribal groups in the world doesn’t and for those who do, kissing was first observed as an act carried out by mothers to pass chewed food to their newborn, toothless infants.

Today, a generally accepted theory as to why humans kiss is that as people move their faces close together, our noses are subconsciously sniffing each other out and our pheromones would exchange biological information in order to determine the suitability of each other in becoming mates to produce a stronger offspring. It seems that people prefer someone whose scent “tells” us that his/her genes have certain immune system proteins that are different from our own thus a union of these two sets of genes could possibly bear an offspring whose immunity would be even stronger. Still – scientific reasoning aside, I’m one of those believer that with the tones of nerves present on our tongues and lips, kissing is simply a pleasure that we get just we try delicious food so who cares really why humans kiss?

References:

Scienceline.org (2006, October 2). “Why do humans kiss?”. Retrieved March 28, 2010, from http://www.scienceline.org/2006/10/02/ask-fiore-kiss/

The Bonobo Page. (2006, April 26). “Bonobo”. Retrieved March 30, 2010, from http://williamcalvin.com/teaching/bonobo.htm”Tiger-kiss,” by tomjude. Stock xchng: iStockPhoto.com. URL: http://www.howstuffworks.com/framed.htm?parent=kissing.htm&url=http://www.sxc.hu/photo/531160 (accessed on 29 Mar 2010)

MAKE WAR NOT LOVE

Creatures of the earth engage in various strange mating behaviors. Male giraffes drink the urine of the females; red-sided garter snakes annually form mating balls of up to 30,000 strong and the reproductive organs of male wasp spiders snap off in the female during reproduction, but ‘penis fencing’? What in the world?

flatworms

Source: http://neatorama.cachefly.net/images/2007-04/flatworm-penis-fencing.jpg

‘Penis fencing’ is an unusual reproductive activity commonly practiced by the marine flatworm (Pseudobiceros hancockanus), which can grow up to about 4-6cm long. Basically, ‘penis fencing’ is an unassuming phrase that biologists use to describe the vicious battle between two hermaphrodite flatworms consisting of each of them trying to stab the skin of the other using one of its two penises. This dual may last an hour and result in gaping wounds on the body of the loser. The ritual is done to facilitate the delivery of sperm from one flatworm to another to ensure reproduction, where the first successful ‘stabber’ becomes the de-facto male and the other, the de-facto female. The de-facto female then has bear the burden of motherhood while healing her wounds.

One might wonder what motivates this seemingly placid creature to engage in such ferocious behavior against its own kind even in the absence of any kind of sex drive. Scientists suggest that it is the result of a cost-benefit analysis, where members of the hermaphrodite population weigh the benefits of stabbing, against the costs of being stabbed. The benefits of stabbing include holding control of the fertilization process and gaining direct access to the eggs under the skin of the de-facto female. In addition, the de-facto males would have the valuable opportunity to pass on their genes to even more offspring while having fewer wounds to heal. On the other end, the costs of being stabbed include expanding copious amounts of energy caring and developing the eggs whilst healing gaping wounds.

Evidently, the tremendous benefits of stabbing another vastly outweigh the costs of being stabbed, which might serve to explain why marine flatworms approach this supposed act of ‘love’ in such a primal, warlike fashion.

References:

“Fighting to mate: Flatworm penis fencing,” by Leslie Newman. PBS, n.d. URL: http://www.pbs.org/kcet/shapeoflife/episodes/hunt_explo2.html (accessed on 5 Apr 2010)

N. K. Michiels & L. J. Newman, 1998. Sex and Violence in Hermaphrodites. Nature, 391: 647.

Flatworms penis fencing by TheAwk.com. TheAwkblog Youtube Channel, 18 March 2009. URL: http://www.youtube.com/watch?v=5fx-YgcP8Gg (assessed on 5 April 2010)

“Spiders sacrifice genitals to ensure paternity,” by Sarah Bartlett. Cosmos Magazine, 9 Mar 2007. URL:http://www.cosmosmagazine.com/node/1093 (assessed on 5 April 2010)

“Giraffes,” by Animalcorner.co.uk. Animal Corner, n.d. URL: http://www.animalcorner.co.uk/wildlife/giraffes/giraffe_about.html (assessed on 5 April 2010)

“The Flatworms” by Lost In Arizona. Scienceray: The Great Barrier Reef: Jewels of the Sea. URL: http://s3.amazonaws.com/readers/2008/09/17/336439_5.jpg (assessed on 5 April 2010)

Till death do us part..

Cold blooded animals like reptiles are not usually associated with being faithful. To put it in a humanise  way, reptiles flirt around with no fix sexual partner throughout its life. However, this particular reptile specie will change your life, my life (just joking) and perhaps our views on cold blooded animals.

Shingleback

Shingleback from Dr Ellen

In reptiles, and lizards in particular, monogamy is rarely reported. However, this lizard(shown above)  is almost the only one that is monogamy. Monogamy is where a single male and a single female form an exclusive association and cooperate in breeding activity (Wickler and Seibt, 1983).

The reptile that is so “faithful” is Tiliqua rugosa, commonly known as Shingleback blue- tongued skink. It is found throughout the drier parts of Southern Anstralia, from approximately Bathurst in New South Wales all the way to the coast of Western Australia. (Loch, T. 2000) Shingleback skinks are among the largest of the Australian skinks. Mature adults typically weigh about 600 to 900 grams and have snout-vent lengths (SVLs) of 16 to 18 inches (VItt and Pianka, 1994).

Enough of the reptile, lets go into the sweetest part of the animal. It is best known for monogamy.

There are several reason why animals choose to be monogamy :

1) Males stay with their female partner to provide paternal care and help to raise young to ensure a higher reproduction rate.

2) Males had to guard their female partner from rivalry to ensure their own paternity.

3) Females adopt monogamy when they are advantaged by accompanying males.

However, these 3 most common reasons/functions of monogamy cannot explain why Shingleback choose to form loyal pairs for up to 20 years (FYI, their average lifespan is 15 years in the wild thus it is effectively “married” for life). So why did Shingleback choose to remain loyal when the apparent functions of monogamy are not applicable to them? Some scientists used the costs VS benefits theory to explain. They explain that it might cost more to break a relationship then to remain with the same partner throughout its life. Thus, in the case of Shingleback, the benefits of staying loyal outweigh the cost of looking for a partner every mating session. Well, i believe that some things cannot be explained using science especially in the field of relationship.

Image from Dr Ellen

The whole duration of courtship take an amazingly long period of time (well, at least in animals). An inseparable courtship stage ensues for 6-8 weeks. In other words, the couple will stay side by side for more than 2 months before they began their mating ritual. This prolong period of courtship is seldom observed in reptiles.  After the copulation, pairs then usually separated for 10 months, after which they seek out the identical partner the following years.  Astonishingly, some pairs have been found together for 10 consecutive years (Vitt and Pianka. 1994). A study done by University of Michigan Museum of Zoology illustrate long-term individual recognition by this specie and also shows that these reptiles are monogamous more often than not (Loch, T.2000).

In the video shown below, we would observe the courtship behaviour exhibited by the Shingleback. I was shocked when i heard that the couple will remain side by side for up to 2 months. The courtship is so “human like” in the way when gentle touching(or licking) is the way of courtship (compared to other reptiles). Towards the last part of the video, the humane side of them shows again. The male would stay with the female after it was dead. It was indeed surprising for a reptile to do that!


Maybe, one day, we should redefine some of our definition or labeling of our cold blooded friends.


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