Kamikaze Ant Fighters

I happened to stumble upon a video on Youtube recently about the “Top 10 Animal Power Moves”. Zooming straight to the top of the list is the Carpenter Ants or Camponotus saundersi. So what power moves do they possess? The Carpenter Ants, found in Malaysia and Brunei, are given the nickname “exploding ants” as they will do just that when confronted with danger.

Not all of the Carpenter Ants have the ability to get into self-destruct mode. It is the worker ants, charged with the duty to defend the colony at all costs, that would use this defence mechanism as the ultimate sacrifice to protect its colony.

These worker ants have greatly enlarged mandibular glands compared to other ants and these glands run the full length of its body. When the ants are under duress, they will contract their abdomens muscles vigorously, causing the glands to implode and spray gluey toxic in all directions and thus immobilizing its predators even if it means at the expense of its own life. They will squirt toxic mainly from its end, from its mouth and through its ruptured exoskeleton.

This process of internal rupturing or autothysis is surprisingly not rare in the animal kingdom. It is popularized by the Carpenter Ants but is also noted in other species like termites and toads.

Most of the time this happened the ants are either confronted with grave danger or fighting a losing battle against predators that are physically bigger. For its predators, the costs of attacking the Carpenter Ants would then outweigh the benefits and make them think twice about pursuing its attack. Talking about ending it with a bang literally. In this case it is a boom.

lsm pic

References:

“Carpenter Ant”. Wikipedia. URL: http://en.wikipedia.org/wiki/Camponotus_saundersi (accessed 02 April 2010)

James Ridley,Blackwell Science,2003. “Questions about Animal Behaviour.” Animal Behaviour 2nd Edition, pg 1-4.

2nd: Jones, T.H.; Clark, D.A.; Edwards, A.A.; Davidson, D.W.; Spande, T.F. and Snelling, Roy R. (2004): “The Chemistry of Exploding Ants, Camponotus spp. (Cylindricus complex)”. Journal of Chemical Ecology 30(8): 1479-1492. doi:10.1023/B:JOEC.0000042063.01424.28

James Ridley,Blackwell Science,2003. “Questions about Animal Behaviour.” Animal Behaviour 2nd Edition, pg 1-4. Figure 1.1 and 1.2

Solid Defence – Armadillos

armadillo-300x225

There are 20 species of Armadillos in the world as we know today.  Armadillo is Spanish for “little armoured one”. The Nine-banded Armadillo, Dasypus novemcinctus, is the most common, spreading from South America into Kansas in the United States. (National Geographic, 2010) They are most closely related to the Anteater and Sloth, and are said to look like rabbits without its armour.

I have always been amazed by the Armadillo’s head to toe hard and leathery armour. It reminds me of a medieval general’s amour, fully plated and ready for war. Unlike many common animals with innate abilities to evade, escape or camouflage themselves when threatened by predators, Armadillos choose to defend itself by utilising its coarse (and awesome) armour in the face of its adversary. Small as a rabbit, brave as a lion, don’t you think so? The armour of the Armadillo is made up of small plates of bones and covered by a later of horny skin.

Armadillos defend themselves by either:

  • Curling itself into a ball, with the exception of the Nine-banded Armadillo, which only defends itself by wedging its feet deep into the soil and grabbing it so that the surrounding armour touches the ground
  • Running swiftly into thorny bushes where its armour will protect it. (Ever Wonder, 2002)

Did you know that Armadillos are good swimmers too? Well, in a fashion, at least. Armadillos can hold their breaths underwater up to a maximum of six minutes! (J Rank, 2010)You can imagine them as armoured submarines, crossing rivers underwater. Their armour is thick and heavy, so they usually sink when they swim. In order to maintain some buoyancy, they inflate their lungs, stomach and intestines with air, which they would if they were crossing a shallow river.

Given their protective armour, it is not unusual to assume that they are peaceful animals. However, male Armadillos show aggression when they are paired with a female, suggesting that this behaviour only arises so as to retain the exclusive rights to the female counterpart. Females also show aggression when they are defending their current litter and dispersing last year’s young. (Collemen, 1994)

References

Collemen, M. (1994). Determinants of aggression in Nine-banded Armadillos. Journal of Mammalogy , 189.

Ever Wonder. (2002). Armadillo’s Protective Armour. Retrieved April 7, 2010, from Nine-banded Armadillo – Pictures photos and information: http://www.everwonder.com/david/armadillo/armor/index.html

J Rank. (2010). Armadillos enjoy water. Retrieved April 7, 2010, from Armadillos: Behaviour and reproduction: http://animals.jrank.org/pages/2748/Armadillos-Dasypodidae-BEHAVIOR-REPRODUCTION.html

National Geographic. (2010). Armadillo. Retrieved April 7, 2010, from National Geographic Animals: http://animals.nationalgeographic.com/mammals/armadillo/

Armadillo,” by Dawn Ashley. Flickr, 30 May 2008. URL: http://www.flickr.com/photos/dawnashley/2536739605/

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


I Toad You!

Bufo lemur

http://www.ryanphotographic.com/bufo%20lemur.htm

Recent  evidence suggests that toads are able to predict earthquakes after researchers observed a mass exodus of toads from a breeding site in L’Aquila, Italy, five days before a major tremor struck.

While anecdotes and folklore have linked unusual animal behavior to cataclysmic events like earthquakes since ancient times, hard evidence has been scarce. Furthermore, even those that have been shown to react, such as fish, rodents and snakes tend to do so shortly before an earthquakes strikes, rather than days ahead of the event.

Toads are known to remain active in large numbers at breeding sites until spawning has finished. However, 96% of the males abandoned the site 5 days before the quake hits, when spawning had barely begun. The number of toads at the site fell to zero three days before the quake and only started coming back the day after it ended. This highly unusual behaviour prompts researchers to surmise that millions of years of evolution could have given the toads the ability to detect impending quakes, triggering them to flee to higher ground, where they would be at less risk from rock falls, landslides and flooding.

Although the exact method used by the toads remains unclear, findings suggest that toads are able to detect pre-seismic cues such as the release of gases and charged particles, and use these as a form of earthquake early warning system.

Hopefully, this will lead to the introduction of a toad-led earthquake early warning system that will prove to be both swift and accurate.

“Toads can ‘predict earthquakes’ and seismic activity” Matt Walker, Earth News, March 31 2010. Retrieved from http://news.bbc.co.uk/earth/hi/earth_news/newsid_8593000/8593396.stm

“Study suggests toads can detect coming earthquakes” Jill Lawless, The Associated Press, March 31 2010. Retrieved from http://www.washingtonpost.com/wp-dyn/content/article/2010/03/31/AR2010033100665.html

Holey Moley!

Grant’s golden mole, or Eremitalpa granti, is perhaps one of the most adorable animals I have ever come across! From its silky smooth sheen, to its barely-there eyes, down to its cute little snout used for ‘swimming’ their way through the sand – doesn’t this prompt everyone to say, “Awww”!

Grant’s golden moles are nocturnal creatures of the desert. These moles often create shallow grooves to the desert sand; because the sand is too fine and loose, the moles are thought to “swim” through the desert surface when travelling or foraging at night. This is why it is sometimes called a sand fish (HowStuffWorks.com, 2008). The reason for such behaviour is thought to arise out of dipping their heads and shoulders into the sand when looking for prey, hence creating the shallow grooves. Observers have associated such head-dipping behaviour with the perception of seismic vibrations made by prey (Matthew J. Mason & Peter M. Narins, 2002). Such behaviour is typical and unique to Grant’s golden moles living in the desert areas.

This swimming behaviour is aided by its physical traits:

  • It has poorly developed eyes that prevent sand from getting in the way of its vision (and is hence considered mostly blind)
  • Its external ear is only a simple orifice hidden under its fur
  • (Mason & Narins, 2002)

  • A leathery flap over its snout prevents dust particles from entering the nostrils, and also helps it to push its way through the sand
  • Its powerful limb muscles and curved claws enable better “swimming”
  • (Piper, 2007)

    With regards to foraging, it is suggested that these creatures locate their prey (termites, geckos, and some invertebrates) via seismic activity in the sand (Mason & Narins, 2002). The middle ear is thought to be able to pick up signals from within the sand dunes, but this has not been directly examined in studies before. Such behaviour is believed to be an adapted trait that evolved as a means of detecting ground vibrations. It is especially advantageous for golden moles because it makes up for the limited visibility and poor propagation of airborne sounds in the desert, thereby finding preys more efficiently.

    References:
    HowStuffWorks.com. (2008, April 22). “Mole”. Retrieved March 30, 2010, from HowStuffWorks.com: http://animals.howstuffworks.com/mammals/mole-info.htm/printable

    Matthew J. Mason & Peter M. Narins. (2002). Seismic Sensitivity in the Desert Golden Mole (Eremitalpa granti): A Review. Journal of Comparative Psychology , 158-163.

    Piper, R. (2007). Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals. Connecticut: Greenwood Publishing Group.

    “The Golden Mole,” by globalzoo. Youtube Channel, 23 Jun 2009. URL: http://www.youtube.com/watch?v=DV3KkpCkjy4&feature=player_embedded (accessed on 31 Mar 2009).