Fantastic Feigners of Injury and Death

The critically endangered St. Helenian Plover

(Charadrius sanctaehelenae) feigning injury 

(Source: Flickr. Image by Burns)

Two weeks ago my boyfriend’s parents came back from a trip away to the remote island of St. Helena Island off the coast of South Africa where they stumbled upon a bird called the wirebird or St. Helenian plover (Charadrius sanctaehelenae) and came back telling me stories of their find. They were able to watch how a nesting pair they found tried to protect their eggs. I was told that one (they were unsure whether it was the male or the female) sat on the nest and refused to budge while the other moved about around the nest and pretended to be injured in the hope that the predator (in this case my boyfriend’s parents) would get distracted by this display and not go after the eggs anymore but instead go after the ‘injured’ parent.

This in known as ‘injury-feigning’ and is relatively common among birds. Many species of doves and plovers have been observed feigning injury (Swrath, 1935) as well as the Florida nighthawk (Ckhordeiles minor chapmani) (Tompkins, 1942) among others. I have even been lucky enough to witness this in a family of Willy Wagtails (Rhipidura leucophrys) in my back yard back in Innisfail. 

Initially, the reason behind this display was thought to be the birds mixed emotions between wanting to flee the nest to get away from a predator and its attachment to its young causing a muscular inhibition and an inability to fly (Friedmann 1934; Tompkins, 1934). Further observations have lead scientists to believe that this behaviour is in fact a device used voluntarily to lure predators away from young. This would prove to be an advantageous behaviour to adopt because the parent is obviously better able to escape the predator than the chicks in the nest (and definitely the eggs if they are unhatched). By acting injured, the predator is alerted of the existence of a larger and more filling meal being available for only a little more work than it would take to get the chicks or eggs. Weighing the cost over the benefits, the predator is then more likely to attempt to attack the ‘injured’ parent. Hopefully, the injured parent will be able to get away at the last moment and the predator will give up on this meal.

Animals are also known to go one step further. Many animals are able to feign death in order to trick their predators into discarding them. This is called letisimilation or thanatosis (Gregory, et al., 2007) and is widespread among the animal kingdom from insects, amphibians and reptiles to birds and mammals (Gregory, et al., 2007). Some examples of the animals that demonstrate this behaviour are the red flour beetle (Tribolium castaneum) (Miyatake, et al., 2008), ant-lions (of the family Myrmeleontidae) (Turner, 1915), some crickets (eg Gryllus bimaculatus), grass snakes (Natrix natrix) (Gregory, et al., 2007) and rough earth snakes (Virginia striatula) among others (Thomas & Hendricks, 1976) to name a few. 

Western hog-nosed snake (Heterodon nasicus) 

feigning death to escape predation

(Source: Arkive. Image by Visuals Unlimited)

The strategy of feigning death is usually used as a last resort when an animal has been captured by a predator and all its other attempts to avoid predation (eg. toxicity, crypsis, group living, predator confusion, pursuit deterrent signals etc.) have failed. Simulated death may be achieved by rolling over onto their back and opening their mouth like the Western hog-nosed snake (Heterodon nasicus), or by releasing chemicals through their skin threat smell as tough they have been dead for a while and slowing their heart rate. By acting as if they are dead they will either confuse the predator for a split second allowing it to escape or the predator will believe the deception and moves on. Either way, feigning death makes them less likely to be eaten by the predator and more likely to reach their goal of passing their genes onto the next generation (Gregory, et al., 2007).

References

Friedmann, H., 1934. The Instinctive Emotional Life of Birds. The Psychoanalytic Review, 21(3 - 4), pp. 1-57.

Gregory, P. T., Isaac, L. A. & Griffiths, R. A., 2007. Death feigning by grass snakes (Natrix natrix) in response to handling by human "predators.". Journal of Comparative Psychology, 121(2), pp. 123-129..

Miyatake, T. et al., 2008. Pleiotropic antipredator strategies, fleeing and feigning death, correlated with dopamine levels in Tribolium castaneum. Animal Behaviour, 75(1), pp. 113 - 121.

Swrath, H. S., 1935. Injury-Feigning in Nesting Birds. The Auk, 52(3), pp. 352 - 354.

Thomas , R. A. & Hendricks, F. S., 1976. Letisimulation in Virginia striatula (Linnaeus). The Southwestern Naturalist , 21(1), pp. 123-124.

Tompkins, I. R., 1942. The "Injury-Feigning" Behavior of the Florida Nighthawk. The Wilson Bulletin, 54(1), pp. 43 - 49.

Turner, C. H., 1915. Notes on the Behavior of the Ant-Lion with Emphasis on the Feeding Activities and Letisimulation. Biological Bulletin, 29(5), pp. 277 - 307.

University of Bath, 2010. The critically endangered St. Helenian Plover feigning injury, photograph, viewed 27 May 2014

< http://farm4.staticflickr.com/3820/12087002524_78b072d4ac_z.jpg>

Visuals Unlimited, n.d., Western hog-nosed snake (Heterodon nasicus) feigning death to escape predation, photograph, viewed 27 May 2014

< http://cdn2.arkive.org/media/C1/C10548AF-A87F-4314-8C1D-8A039B127130/Presentation.Large/western-hog-nosed-snake-ssp-kennerlyi-feigning-death.jpg>

An alluring meal or a luring trap? More deceptive tricks animals use to get an easy meal

Continuing on for last week, here are a few more animals that have devised ways to trick their prey into coming to them so they can sit back, relax and enjoy the meal.

Striated Heron (Butorides striata) using a dragonfly to lure fish

(Source: Biodiversity Explorer. Image by DeWet)

Herons

While there are many animals that have specialised appendages in order to lure their prey in, not all are so lucky. Some species of heron have not let this discourage them. Green Herons (Butorides virescens), Squacco Herons (Ardeola ralloides), Striated Herons (Butorides striata) and Goliath Herons (Ardea goliath) have all learnt that if they place a flower, a feather, a stick an insect or some other item in the water, that that they can trick fish into coming toward what they think is a food item and get an easy feed (Gavin and Solomon, 2009; Ruxton and Hansell, 2011). This method is thought to have evolved from ‘passive bait fishing’ where birds take advantage of fish being attracted to intimate objects floating by in the water (Ruxton & Hansell, 2011).

Assassin bug Stenolemus bituberus

(Source: Die Raubwanzen der Welt. Image by Jestis)

Assassin Bugs

The assassin bug (Stenolemus bituberus) has a dangerous choice of food; spiders. To get a meal they risk facing a counter attack by the spider that could possibly kill them resulting in the assassin bug becoming the prey. To lower the chances of being attacked, assassin bugs have devised a way to seize spiders when they least expect it; when they are lining up for their dinner. The assassin bug will go up to the edge of a spider’s web and shake it. The spider, thinking an insect has gotten itself caught in the sticky web, comes down to eat it but instead gets attacked by the assassin bug. The assassin bug attacks by piercing its rostrum into the animal and injecting it with its venom, paralysing it. The assassin bug then proceeds to suck the juices out of the insect (Wignall & Taylor, 2009).

Even when not hunting spiders, the assassin bug can still be deceptive. When the assassin bug stalking its prey, as it gets close it alters its footsteps to an uneven pattern so that it blends in with the background noise of the wind moving the plants (Wignall & Taylor, 2009). The poor animal never knew what hit it!

Capable of pulling the face made famous by a particular boot wearing

cat in the movie ‘Shrek 2’, you would never have expected that the 

Margay was capable of dishonesty and deception.

(Source: Fotopedia. Image by unknown)

Margays

While Dr. Fabiano Calleia was studying tamarin monkeys in Brazilian rainforest, he heard the sound of a distressed tamarin pup in the distance. This greatly disturbed the other tamarin monkeys in the troop he was following and they went off to find the defenceless pup. To his astonishment, Dr. Calleia saw that it was not actually a tamarin pup but a margay (Leopardus wiedii) mimicking the sound of a distressed pup to lure the other tamarin monkeys closer (Angier, 2010). Luckily, the tamarin monkeys realised this was the case and a sentinel money screamed and the troop escaped unharmed. While vocal mimicry has been observed in bottlenose dolphins (Tursiops truncatus), harbour seals (Phoca vitulina), killer whales (Orcinus orca), orangutans (Pongo spp.) and African savannah elephants (Loxodonta africana) (Kelley & Healy, 2011), to date, this is the only confirmed case of vocal mimicry used to attract prey.

References

Angier, N., 2010. Why copycats have nine lives; Aping your prey is just one of many surviving-by-disguising strategies in the animal kingdom. Edmonton Journal, p. E.2.

Capable of pulling the face made famous by a particular boot wearing cat in the movie ‘Shrek 2’, you would never have expected that the Margay was capable of dishonesty and deception, n.d., photograph, viewed 20 May 2014

<http://de.fotopedia.com/items/flickr-771396288> 

DeWet, C, n.d., Striated Heron (Butorides striata) using a dragonfly to lure fish, photograph, viewed 20 May 2014
<http://www.biodiversityexplorer.org/birds/ardeidae/butorides_striatus.htm>

Jestis, D, n.d., Assassin bug (Stenolemus bituberus), photograph, viewed 20 May 2014
<http://www.reduviidae.de/systematik/emesinae/stenolemus.html>

Gavin, M. C. & Solomon, J. N., 2009. Active and Passive Bait-Fishing by Black-Crowned Night Herons. The Wilson Journal of Ornithology, 121(4), pp. 844 - 845.

Kelley, L. A. & Healy, S. D., 2011. Vocal mimicry. Current Biology, 21(1), pp. R9- R10.

Ruxton, G. D. & Hansell, M. H., 2011. Fishing with a Bait or Lure: A Brief Review of the Cognitive Issues. Ethology, 117(1), pp. 1 - 9.

Wignall, A. E. & Taylor, P. W., 2009. Alternative predatory tactics of an araneophagic assassin bug (Stenolemus bituberus). Acta Ethologica, 12(1), pp. 23 - 27.

An alluring meal or a luring trap? Ways animals deceive and entice their prey

If pizza didn’t cost extra to get delivered, I doubt anyone would ever make all that effort to drive ALL the way to the store, wait around cos it still isn’t finished and then drive ALL the way home again. We would much rather our meals came to us. The same goes for animals.

There are many deceptive animals out there that will do anything to get out of having go and hunt for their food. Many have to chase their prey and this often requires a lot of energy. In some cases, the predator may even risk their life in the pursuit of their prey. Obviously, it is much more beneficial for the animal to save this energy if it can, so what is the logical course of action to take? Lure your prey in!

Cantil snake (Agkistrodon bilineatus taylori) displaying its tail

(Source: The Gardens of Eden. Image by Kerr)

Cantil

Found in northern Mexico and Central America (ref), the highly poisonous Cantil snakes (Agkistrodon bilineatus taylori) are rather stocky snakes and for that reason are pretty hopeless at moving at any great speed (Parkinson, et al., 2000). To obtain their prey they use the tip of their tail. The tip of their tail is thin and often yellow or off white in contrast to their thick dark coloured bodies and resembles a wriggling worm; the prey of many of the Cantil snakes favourite food. A little critter will then come along, see a delightful treat and end up becoming the treat for the Cantil snake instead.

Alligator Snapping Turtle (Macrochelys temminckii) displaying its tongue

(Source: 8tracks, Image by unknown)

Snapping turtle

Alligator snapping turtles are slow moving and rather good at looking like a rock. In order to catch their prey they sit at the bottom of the water with their mouth open wiggling their tongue in the current to make it look like a little worm and wait (East, et al., 2013). Eventually an intrigued fish will come along and the alligator snapping turtle will bear down on the unsuspecting fish with the second strongest jaw pressure bite of any other animal in the world!

Tasselled Wobbegong Shark (Eucrossorhinus dasypogon)

(Source: svdelos.blogspot.com. Image by unknown)

Wobbegong

Wobbegong sharks are found predominantly in Australia and their name means “shaggy beard” in one of the many indigenous languages. Wobbegongs use their frilly appendage to break up their outline to better camouflage them selves but it serves another purpose. Their “shaggy beard” also lures in small fish for them to feast on (Motta & Wilga, 2001).

While there are 12 species of shark which are commonly referred to as wobbegongs, one stands out above the rest for its deceptive abilities. The tasselled wobbegong shark (Eucrossorhinus dasypogon) employs another, more effective, technique to obtain a hearty meal. It also moves its tail about like a small fish. The tasselled wobbegong shark tail is even somewhat forked tipped and in some cases they even have a fake eye making their deception even more convincing.

A female Photuris versicolour eats a male Photinus ignightus

(Source: Cornell Chronicle. Image by Eisner)

Photuris firefly

The Photuris firefly is especially skilled at gaining from their use of deceitful actions. A Photuris firefly preys upon male Photinus fireflies. The poor Photinus fireflies go about regular firefly courtship routine and emit flashes of light at a frequency unique to their species. Males fly above the ground while the females, who’s wings are too small to fly, rest on the ground watching their potential suitors fly overhead (Eisner, et al., 1997). Meanwhile, the conniving Photuris firefly sits and studies other female fireflies in order to mimic their flashing patterns. When a male sees this copied pattern he thinks it is a female of his own species and descends prepared to mate with the lovely maiden below. The result of this encounter is not procreation but ingestion of the male Photinus firefly by the Photuris firefly (Eisner, et al., 1997).

The Photuris firefly gets a many benefits out of this tactic. Obviously, he gains a meal helping him to increase fitness and ability to produce offspring. Furthermore, by eliminating his rivals he lessens the competition he has to face with other fireflies for resources. These things considered, perhaps the most devious outcome is one of toxicity. While Photuris fireflies are not toxic when they are born, by consuming naturally toxic Photinus fireflies they assume their chemical defence (chemical compounds called lucibufagins) (Eisner, et al., 1997).

References

Alligator Snapping Turtle (Macrochelys temminckii) displaying its tongue, n.d., photograph, viewed 13 may 2014
<http://i.imgur.com/9koX3GL.jpg>

East, M. B., Fillmore, B. M. & Ligon, D. B., 2013. Feeding Behavior of Captive-Reared Juvenile Alligator Snapping Turtles (Macrochelys temminckii). Southeastern Naturalist, 12(4), pp. 692 - 702.

Eisner, T., 1997, A female Photuris versicolour eats a male Photinus ignightus, photograph, viewed 13 May 2014
<http://www.news.cornell.edu/sites/chronicle.cornell/files/fireflyeatingmale.72.JPEG>

Eisner, T. et al., 1997. Firefly "femmes fatales" acquire defensive steroids (lucibufagins) from their firefly prey. Proceedings of the National Academy of Sciences of the United States of America, 94(18), pp. 9723 - 9728.

Kerr, M. D., 2011, Cantil snake (Agkistrodon bilineatus taylori) displaying its tail, photograph, viewed 13 May 2014
<http://www.thegardensofeden.org/p169755082/h3B5F7EE#h3b5f7ee>

Motta, P. J. & Wilga, C. D., 2001. Advances in the Study of Feeding Behaviors, Mechanisms, and Mechanics of Sharks. Environmental Biology of Fishes, 60(1), pp. 131 - 156.

Parkinson, C. L., Zamudio, K. R. & Greene, H. W., 2000. Phylogeography of the pitviper clade Agkistrodon: historical ecology, species status, and conservation of cantils. Molecular ecology, 9(4), pp. 411-420.

Tasselled Wobbegong Shark (Eucrossorhinus dasypogon), 2013, photograph, viewed 13 May 2014

<http://lh4.ggpht.com/-f4N-NS_73Mc/UnMxLxD5kLI/AAAAAAAAKT4/He3EFu7_bjA/%2525281%252529_thumb%25255B1%25255D.jpg?imgmax=800>

Liar, liar, pants on fire!

Lying. We all do it (some of us better than others), but why?

Liar (Source: Glen the Great. Image by unknown)

Did you ever play the game in primary school Two truths and a Lie? The aim of the game is to have a person tell 2 truths and 1 lie and the other person has to work out which one is the lie. Here goes…

1. My boyfriend’s Father was born in Sweden and his mother was born in Uganda

2. I went to Canada on a high school band camp

3. Every one of my mother’s 5 siblings have owned a small business at some point in their lives

So which one do you think is the lie?

Despite the little games we play, lying is an important part of human existence. Because of our ability to lie, an individual has the opportunity secure itself more food, more mates and perhaps most importantly, good social standing with their peers. All of these things are not guaranteed though. The individual needs to be able to lie well and escape detection from the people they are lying to. Equally, they need to be able to detect liars so they themselves are not duped.

Learning to lie and detect liars takes a lot of time to develop. We start lying at a surprisingly young age. 6 months according to Gray (2007). You have probably seen this yourself. A baby sits crying in their crib. Their bawling is interrupted by a short pause where he/she looks around to see if anyone is coming to give them attention and if no one is there they resume their wailing. 3 years later and she is lying to mum about who really broke her little sister’s toy horse. By 15 she is telling mum she is going over her friends place to study after school (wink wink). By the time she is an adult she will most likely tell an average of 3 lies in a 10 minute conversation (Meyer, 2011).

Some people are so advanced at lying that they can actually lie to themselves. This is known as self-deception (Bayne & Fernandez, 2009). This occurs when a person holds two pieces of contradicting information in their mind but only pays attention to one. This is often the case for pathological liars. According to Mele (1983), when pathologiacal liars tell a lie is possible for them to believe wholeheartedly that what they are saying is the truth. That is not all though.

Grey and White Brain Matter

(Source: Medical News Digest. Image By Unknown)

Studies conducted by Yang et. al. (2005) showed that pathological liars had significantly different brain structure compared to normal people. They found that the prefrontal cortex of liars had around 25% more white matter (the part of the brain that connects everything together) and 14% less grey matter (the part of the brain that processes information) when compared to normal controls (Yang , et al., 2005). This essentially means that pathological liars have a heightened ability to make connections in their brain and therefore keep track of all the information due to the increased white matter. The trade-off is in the reduced amount of grey matter which correlates to our ability to think critically about (in this case) the implications of the lie being told.

As we all grow older we learn how to lie, who is good at detecting our lies and what lies we can get away with (McCann, 1998). So how advanced are you? Which of the 3 options given earlier did you think was the lie? Do you think it is unlikely that my boyfriend has such a diverse heritage? Do you doubt that a small high school in Innisfail would take their band all the way to Canada? Or do you think it is beyond belief that my mothers 4 sisters and 1 brother have ALL owned small business in their lifetime? If you guessed option 2 “I went to Canada on a school band camp” you are correct. My boyfriend’s father is Swedish and his mother was born in Uganda (to English parents though), and my aunties and uncles do all have businesses (most in farming), but I have actually never left the country (although just for your information, I do know that quite a while ago my high school did actually send their band over to Innisfail, Canada on a band camp but it was before I was born.)

References

Bayne, T. & Fernandez, J., 2009. Delusion and Self-Deception. New York: Psychology Press.

Gray, R., 2007. Babies not as innocent as they pretend. The Telegraph, 1 July.

Grey and White Brain Matter, n.d., photograph, viwed 5 may 2014

<http://www.medinewsdigest.com/wp-content/uploads/2011/12/Brain_Cortex_Harvard-e1323835780229.png>

Liar, n.d., photograph, viewed 5 May 2014

<http://glennthegreat.com/wp-content/uploads/2012/05/liar.jpg>

McCann, J. T., 1998. Malingering and Deception in Adolescents: Assessing Credibility in Clinical and Forensic Settings. Washington, DC: American Psychological Press.

Mele, A. R., 1983. Self-Deception. The Philosophical Quarterly, 33(133), pp. 365-377.

Meyer, P., 2011. How to spot a liar. Video recording: TED.

Yang , Y. et al., 2005. Prefrontal white matter in pathological liars. The British Journal of Psychiatry, Volume 187, pp. 320-325.