LSM1303 Animal Behaviour

I almost thought that it was a joke when I read this. What would you think of the zoo if I told you that it actually tried to expelled a penguin couple from the colony?

This pair of penguins above are actually a pair of gay couple from Polar Land in Harbin, northern China. After repeated attempts of stealing eggs from other heterosexual couples in the colony, the zoo has decided to segregate them from the rest to prevent any disruption during the hatching season. The newspapers’ interview with a keeper at Polar Land has revealed that, ‘the gay couple had the natural urge to become fathers, despite their sexuality’.

I was really reactive and a little upset towards this article because of the repeated used and focused on the fact that the penguins are gay and that there’s some problem with their sexuality. Males often look after young and in some Penguin colonies the males hatch the offspring. As mentioned by the zookeeper, “One of the responsibilities of being a male adult is looking after the eggs. Despite this being a biological impossibility for this couple, the natural desire is still there”. Therefore, we should be glad that these penguins are naturally responsible, instead of stressing on the differences in their sexuality.

Aren’t we just judging them based on values of our human society, if we call them gay? Furthermore, there are numerous examples of homosexuality in the animal kingdom, as seen from this National Geographic video, named Wild Sex, more than 450 species of animals in the world engages in homosexual behaviors. According to Bagemihl (1999), these animals’ meanings towards same sex sexual behaviors are different. It has other social connotations and they are welcome or tolerated within their kingdom. But of course, I am not saying that we should be the same in this human world, it would be chaotic, since we have different meanings prescribed to our sexual behaviors.

I just feel that even if we do not celebrate this diversity within animals, we should still rethink about how are we viewing other animals, or even towards other people. Are we judging them based on our own value systems?

References

Bagemihl, B. (1999). Biological exuberance: Animal homosexuality and natural diversity. New York: St. Martin’s Press.

Unknown. (28th November 2008). Gay penguins steal eggs from straight couples. China daily. Retrieved April 13th, 2008, from http://www.chinadaily.com.cn/china/2008-11/28/content_7251010.htm.

National Geographic: Wild Sex. Accessed 12th April, 2009. http://www.youtube.com/watch?v=7RlTAyNI8WE&feature=related

Source: National Geographic http://animals.nationalgeographic.com/animals/mammals/humpback-whale.html

Do you know that only the male humpback whales sing? Male humpbacks often sing when a female is present. Traditional explanation has it that male humpbacks sing to court the females and females are especially attracted to songs that are currently in trend. Songs which are out-of-date will fail to get the ladies’ attention and the males will need to constantly update themselves with new songs in this game of love according to cognitive neuroscientist Eduardo Mercado III of the State University of New York in Buffalo.

Joshua Smith, a doctoral student at the University of Queensland in St. Lucia, Australia who has spent three migration seasons collecting the songs of humpback whales supported this traditional explanation of why male humpbacks sing. According to Smith, it is during the migration periods that male humpbacks emit verbal communication that sound like barks, chirps, and moans. Smith believes that male humpbacks use songs to court the females and the way the males structure their songs (for instance, higher or lower frequencies) reflect the traits and characteristics of the male.

Interestingly, songs sung by the male humpbacks not only attract the females but the other males as well. Scientists said that this may be a strategy used by the males to locate a female as another singing male may have a female in his presence. On the other hand, Jim Darling, a Whale Trust researcher who has been studying the male humpbacks song for 25 years suggests that male humpbacks may sing to recruit male allies to help locate a female and act as the primary escort should the female attempt to bolt off.

However, there are other interesting arguments and findings that do not support the traditional explanation of male humpbacks singing to get the girls. Eduardo Mercado of the State University of New York in Buffalo argues that male humpbacks sing not to court the ladies but to navigate new locales. Mercado suggests that male humpbacks sing to locate the others as it can be challenging to rely on just listening in the complex underwater world. The males make use of singing to determine the distance the sound has travelled. Though there is no direct evidence that support his argument, Hawaii Institute of Marine Biology bioacoustician Whitlow Au agrees that Mercado’s idea is “interesting and reasonable”.

Thus, whether or not male humpbacks sing to get the girls is still a question mark. While traditional explanation has it that they sing to attract the females, there is still no direct evidence that support the males sing to court the ladies. Further researches and studies need to be done in order to ascertain if humpback songs are used for courtship

References

Stephanie Peatling. (September 15, 2006). Humpback Whale Calls Are Love Songs, Biologist Suggests. Retrieved April, 13 2009 from http://news.nationalgeographic.com/news/2006/09/060915-humpback-whales.html

Douglas H. Chadwick. (January 2007). What Are They Doing Down There. Retrieved April, 13 2009 from http://ngm.nationalgeographic.com/2007/01/humpback-whales/chadwick-text/6

Charles Q. Choi. (December 6, 2007). Why Whales Sing. Retrieved April, 13 2009 from http://www.livescience.com/animals/071206-sound-whales.html

Darling, J. D., & Berube, M. (2001) Interaction of singing humpback whales with other males. Marine Mammal Science, 17 (3), 570-584.

Mosquitoes have their own ways of attracting a compatible mate. In one species, the Aedes aegypti—popularly known as the culprit of Dengue Fever–mates are capable of harmonizing, performing love duets, by subtly adjusting their buzz frequencies using their wings.

The study done by Ronald Hoy of Cornell University in New York and his associates recorded the wing-flapping frequencies of mosquito pairs and discovered that in approximately 70 percent of the pairs tested, both mosquitoes altered their wing-flapping speeds to synchronize their frequencies to a love duet of approximately 1,200 Hertz.

In general, the male’s wing-beat frequencies ranged between 550 to 650 Hertz while the female’s ranged between 350 to 450 Hertz. And how this works is that when a male approaches a female, she will flap a tune and wait for him to respond in harmony. If the duet converges at a frequency of 1,200 Hertz, she will mate with him.

The team of researchers deems such a form of sexual selection as the female’s way of measuring a male’s fitness before mating. As commented by Hoy, “We think what the females are doing is saying, “Can you match this harmonic, and how fast does it take you to match it?”

This phenomenon is not new, as seen from an earlier study in 2006, which revealed that another mosquito species, Toxorhynchites brevipalpis, also made use of alteration in wing-beat frequencies to match each other’s tones in search of the opposite sex (Gibson& Russell, 2006).

For coverage of the full article, please view it from: http://www.livescience.com/animals/090108-mosquito-love-songs.html

For audio version of mosquitoes’ harmonics, please view it from:

Download

References:

Jenna Bryner. (08 January 2009). Bug Love: Mosquitoes Sing Duet in Harmony. LiveScience. Retrieved on April 12, 2009 from http://www.livescience.com/animals/090108-mosquito-love-songs.html

Cator, L.J., Arthur, B.J., Harrington, L.C. &, Hoy, R.R.(2008). Harmonic convergence in the love songs of the Dengue Vector Mosquito. Science Express, 323(5917), 1077-1079

Gibson, G & Russell,I.(2006). Sexual Recognition in Mosquitoes. Current Biology, 16(13), 1311-1316

Video extracted from:

http://www.sciencemag.org/content/vol0/issue2009/images/data/1166541/DC1/1166541s1.mov

Nora, an adopted grey tabby, has won fame for playing the piano. This rare behavior was apparently self-taught or innate, when she climbed on top of a Yamaha Disklavier piano in the middle of the night and began to play. The couple who adopted Nora owns an art and music studio, where students play the piano in the day. The owners of Nora observed that she has a preference to play on the Yamaha Disklavier piano, even though there are other pianos in their studio. She also includes black keys in her music (http://www.youtube.com/watch?v=TZ860P4iTaM), and plays duets with the students (http://www.youtube.com/watch?v=v0zgQAp7EYw).

From both videos, it does seem like Nora is musically inclined and not just “fooling around” with the piano. Is her sense of music innate or is there some other reason for her bahavior? A 2001 National Geographic article “Do Animals Have an Innate Sense of Music” suggests that animals, including birds and mammals like whales use many musical concepts, such as rhythm, phrase lengths and song structure in their communication. This may help to explain Nora’s sense of rhythm when playing the piano.

However, a piano is an unnatural musical instrument for an animal. Although the owners claim that Nora is self-taught, one might think it’s more probable that Nora might have went through “observational learning”, where the owners taught students to play the piano in the day when Nora was around. Since Nora was also described as being attention loving, the huge amount of attention thrown onto her following her piano-playing incident might have served as a positive reinforcement for her to do it again.

While the rare behavior of Nora has yet been explained satisfactorily, it is most reasonable to suspect that an interplay of the cat’s innate musical abilities and subsequent learning through observation can account for the phenomenon.

References

“Do Animals Have an Innate Sense of Music?”, by Jen Mapes. National Geographic, 05 Jan 2001.

“Nora (Cat)“, Wikipedia. Date accessed: 12 Apr 2009.

Photo Credit: Raymond Hamaker

An Atlantic blacktip shark, Carcharhinus limbatus, was pregnant even though there were no male blacktips in her tank for the past eight years. Scientists were surprised during an autopsy of the now deceased shark to find she had been carrying a baby. Genetic testing has confirmed that the shark pup that had been developing inside the blacktip shark contained only DNA from its mom.

The blacktip shark and the hammerhead are two of at least 70 vertebrate species, including Komodo dragons and captive snakes, that can carry out this type of reproduction.

This asexual reproduction characteristic is called automictic parthenogenesis and is characterized by the fusion of an ovum with its sister cell that became a surrogate sperm to produce a zygote that has only DNA from the mother.

Researcher Demian Chapman, a shark scientist of the Institute for Ocean Conservation Science at Stony Brook University in New York, thinks that this is something that fundamentally many female sharks can probably do. There are a growing number of instances where captive female sharks have produced offspring despite extended periods of isolation from males. Such sharks could have evolved parthenogenesis as a means to avoid reproductive failure in situations when males are scarce within isolated habitat.

“Even though these sharks don’t seem to need a male around to make babies, they shouldn’t ditch sexual reproduction altogether,” Chapman said. For one, the blacktip and hammerhead sharks that reproduced without mating only produced one pup, rather than an entire litter. In addition, Chapman warned that pups born to such a parent could suffer from weakened immune systems, because the fertilized eggs have less genetic diversity than those of pups born to two parents. With fewer types of disease-fighting genes, offspring could be ill-equipped for a battle against illness.

For more information about this article, please do visit http://www.livescience.com/animals/081010-shark-virgin.html#comments.

References:

Jeanna Bryner. (10 October 2008). Shark Pregnant, No Males Required. LiveScience. Retrieved on April 9, 2009 from http://www.livescience.com/animals/081010-shark-virgin.html#comments.

Chapman, D.D., Firchau, B., Shivji, M.S. (2008). Parthenogenesis in a large-bodied requiem shark, the blacktip Carcharhinus limbatus. Journal of Fish Biology, 73, 1473-1477.

More references on Parthenogenesis:

LiveScience Staff. (22 May 2007). Virgin Shark Gives Birth. LiveScience. Retrieved on April 9, 2009 from http://www.livescience.com/animals/070522_asexual_sharks.html.

Chapman, D.D., Shivji, M.S., Louis, E., Sommer, J., Fletcher, H., & Prodohl, P.A. (2007). Virgin birth in a hammerhead shark. Biology Letters, 3, 425-427.

Jeanna Bryner. (24 January 2007). Eggs Crack Open in Komodo Dragon’s Virgin Births. LiveScience. Retrieved on April 9, 2009 from http://www.livescience.com/animals/070124_baby_komodos.html

Unknown. (2006). Parthenogenesis in Komodo dragons. Nature, 444, 1021-1022.