Projectile use by non-human organisms
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/5f/Archerfish_%28PSF%29.png/220px-Archerfish_%28PSF%29.png)
Although projectiles are commonly used in human conflict, projectile use by organisms other than humans is relatively rare.
Animals
Liquid projectiles
![](http://upload.wikimedia.org/wikipedia/commons/thumb/c/ca/African_bush_elephant_%28Loxodonta_africana%29_spraying_water.jpg/220px-African_bush_elephant_%28Loxodonta_africana%29_spraying_water.jpg)
Most projectiles used by terrestrial animals are liquids. Among invertebrates there are a number of examples. Velvet worms can squirt out a slimy adhesive fluid from glands on the sides of their head, and use it to trap their prey. The spitting spiders Scytodes can spit a venomous sticky fluid that traps its victims and also poisons them.[1] The bombardier beetle is unusual by using a violent exothermic chemical reaction to launch a boiling noxious chemical spray in a rapid burst of pulses from special glands in its abdomen, accompanied with a popping sound. The Anthia (oogpister beetle) will fire formic acid at attackers, probably extracting the formic acid from the ants that it eats. The devil-rider stick insects (Anisomorpha) can fire terpenes from glands on the metathorax that can cause an intense burning irritation of the eyes and mouth of potential predators. Wood ants will spray acid at attackers. A type of planthopper of Madagascar is able to flick small balls of honeydew, this attracts day geckos that feed on the honeydew and whose presence may deter predators from approaching the sap-sucking insect.[2] Termites of the subfamily Nasutitermitinae can project a sticky fluid from a nozzle on their heads. They can use this fontanellar gun accurately, over a range of many centimeters, even though the termite is blind, possibly using auditory or olfactory cues instead.
A number of vertebrates also use liquid projectiles. The archerfish will squirt water from its mouth to dislodge invertebrates from overhanging branches. Some diptodactyline geckos can fire a black or pale yellow sticky fluid out of glands in their tail for a distance of about a meter, and with good aim. This fluid has a musky unpleasant odour and although it is not toxic it may discourage predators, in particular the big arthropods that prey on these geckos.[3] The spitting cobra can squirt venom from forward-facing holes in its fangs.[4] It aims for its victim's eyes, spitting up to 1.5 m. The venom may cause blindness. The Mangshan pitviper is also reported to spit venom.
A bird that uses liquid projectiles in defense is the southern giant petrel which produces a stomach oil made up of wax esters and triglycerides that are stored in the proventriculus and can be projectile vomited on predators. Other petrels such as the fulmar can also squirt oils from their mouths as a defense. They can squirt oils with accuracy up to a distance of 1 to 2 meters. The oil mats the feathers of birds together and destroys their waterproofing abilities, so oiled birds may die from chilling or drowning, although fulmars seem able to remove the oil from themselves by preening. Birds ranging from gulls to sea-eagles have died after being squirted by fulmars.[5] Some species of penguin expel liquid feces in a projectile manner, to a distance of up to about 50 cm. They are believed to do this because during the brooding season, when penguins are sitting on their nests, they avoid leaving their nests and thereby leaving their eggs open to predation and thus to maintain a clean nest they evolved the ability to project their feces.[6]
Among mammals, skunks can eject a noxious fluid from their anal glands. It is not only foul smelling, but can cause skin irritation and, if it gets in the eyes, temporary blindness. When it feels threatened a camel will bring up their stomach contents, along with saliva, and project it out towards the threat to distract, surprise, or bother the threat.[7]
Solid projectiles
Some New World tarantulas have a dense covering of hairs called urticating hairs on the abdomen that they sometimes use as protection against enemies.[8][9][10] Species with urticating hairs can kick these hairs off; they are flicked into the air at a target using their back pairs of legs. These fine hairs are barbed and designed to irritate and can be lethal to small animals such as rodents. The symptoms range from a burning itch to a minor rash, from being lethal to simply being a deterrent. With humans, they can cause irritation to the eyes, nose, and skin, and more dangerously, the lungs and airways, if inhaled. In some cases, tarantula hairs have caused permanent damage to human eyes.[citation needed] Urticating hairs do not grow back, but are replaced with each moult. Another invertebrate, the antlion, also makes use of solid projectiles. The antlion lies at the bottom of a sloping pit that it digs in the sand. Small prey slip into the pit on the loose substrate. If the prey crawls up the slopes of the pit, the antlion throws sand at the prey, which may dislodge it and send it back down the pit.[11] In gastropods, cone snails have modified radula tooth which is stored in the radular sac and at the end of proboscis, acting like a harpoon. Their "harpoon" is venomous, which assists cone snail to paralyze or kill the prey before eating it.
A number of vertebrate species also make use of solid projectiles. Among birds the hornbill uses projectile motion to eat food. The hornbill's beak typically only contacts at the tip, and it has a short tongue. To swallow food the hornbill instead throws the food from the tip of its long bill backwards into the throat.[12] One example of solid projectile use among mammals is the California ground squirrel, which is known to distract predators such as the rattlesnake and gopher snake from locating their nest burrows by kicking sand into their eyes.[13] A wild female African elephant has also been observed to throw various materials at an interfering rhino.[14] Orcas have been observed to throw seal prey using their tail flukes in apparent play behavior.[15] Some primates, including humans, can throw objects such as rocks, sticks, and feces as projectiles. Primates that are known to throw are humans, bonobos,[16] chimpanzees,[17] gorillas,[18] orangutans,[19] capuchins,[20] certain gibbons[21] and perhaps some baboons[22] and Japanese macaques[23] (although not rhesus macaques).[24] A chimpanzee named Santino in a Swedish zoo was observed to stockpile stones to be used as missiles against visitors.[25]
Tethered projectiles
![](http://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Chameleon-Stage_03.jpg/220px-Chameleon-Stage_03.jpg)
Chameleons, frogs and some lungless salamanders have tongues that act like a tethered projectile. In frogs, the tongue is attached at the front of the mouth and rotates about this attachment as it flips out (thus the top of the tongue at rest becomes the bottom when extended). In chameleons, the tongue contracts against a tapered hyoid bone, eventually slipping off and projecting forward at very high speed. Lungless salamanders use a similar method, however, both the tongue and underlying hyoid bone project (in contrast to chameleons, whose hyoid remains fixed while the fleshy portion of the tongue projects).[26] In both salamanders and chameleons, the movement is too fast and requires too much mechanical power for muscle alone to provide – instead, muscles slowly pre-load elastic elements such as connective tissue, which can then recoil and release the stored energy at a much higher rate.[27][28] In order to retract their tongues over such great distances, the tongue muscles of chameleons have perforated Z-disks, allowing each sarcomere to shorten far greater distances than those of other vertebrates.[29]
Bubbles
The pistol shrimp claw has a pistol-like feature made of two parts. A joint allows the "hammer" part to move backward into a right-angled position. When released, it snaps into the other part of the claw, emitting an enormously powerful wave of bubbles capable of stunning larger fish and breaking glass.[30]
Plants and fungi
The seed pods of the orange jewelweed have projectile seeds that, if ripe, explode out of the pods when they are lightly touched. The seed pods of the scotch broom also burst open, often with an audible crack, projecting the seeds from the parent plant. Similarly, the fruit of the sandbox tree burst open to disperse seeds, but the reaction is so violent that it can injure nearby people or livestock.[31] Some plants such as the dogwood bunchberry and white mulberry will also fling pollen from their flowers. Peat mosses are known to explosively launch their spores.[32]
Hat-throwing fungi fire their spore capsules up to 2 m,[33] and the cannonball fungi of the genus Sphaerobolus, such as S. stellatus, the artillery fungus can throw sticky spore sacs up to 6 m horizontally.[34][35] This species is phototropic, and propels spores towards the nearest source of direct or reflected light, like the sides of brightly colored houses.[36]
References
- ^ Yap, L.-M. Y. L.; Li, D. (2009). "Singaporean spiders spit venomous glue, work together, eat each other | Not Exactly Rocket Science | Discover Magazine". Journal of Zoology. 278. Blogs.discovermagazine.com: 74–81. doi:10.1111/j.1469-7998.2009.00555.x. Retrieved 2012-10-21.
- ^ "Science/Nature | Gecko 'begs' insect for honeydew". BBC News. 2008-02-16. Retrieved 2012-10-21.
- ^ Naish, Darren (2010-04-28). "Squirting sticky fluid, having a sensitive knob, etc. (gekkotans part III) – Tetrapod Zoology". Scienceblogs.com. Retrieved 2012-10-21.
- ^ "How spitting cobras shoot for the eyes | Not Exactly Rocket Science | Discover Magazine". Blogs.discovermagazine.com. 2010-05-14. Retrieved 2012-10-21.
- ^ Naish, Darren. "Living the pelagic life: of oil, enemies, giant eggs and telomeres (petrels part II)". Scientific American. Retrieved 2012-10-21.
- ^ Batts, Shelley (2007-07-07). "Science Vault: Projectile Penguin Poop Pressures – Retrospectacle: A Neuroscience Blog". Scienceblogs.com. Archived from the original on 2011-08-11. Retrieved 2012-10-21.
- ^ "San Diego Zoo's Animal Bytes: Camel". Sandiegozoo.org. Retrieved 2012-10-21.[dead link]
- ^ Cooke, J.A.L., Roth, V.D., Miller, F.H. (1972). The urticating hairs of theraphosid spiders. American Museum Novitates 2498.
- ^ PDF (12 Mb)
- ^ Miller, Frederick H.; Roth, Vincent D.; Cooke, John A. L. (July 21, 1972). "The urticating hairs of theraphosid spiders". American Museum Novitates (2498). hdl:2246/2705.
- ^ Fertin, Arnold; Casas, Jérôme (2007). "Orientation towards prey in antlions: efficient use of wave propagation in sand". Journal of Experimental Biology. 210 (19): 3337–3343. doi:10.1242/jeb.004473. PMID 17872987.
- ^ Naish, Darren (2011-06-22). "An introduction to hornbills – Tetrapod Zoology". Scienceblogs.com. Archived from the original on 2012-05-03. Retrieved 2012-10-21.
- ^ Coss, Richard G. (1997). "Individual Variation in the Antisnake Behavior of California Ground Squirrels (Spermophilus beecheyi)". Journal of Mammalogy. 78 (2): 294–310. doi:10.2307/1382883. JSTOR 1382883.
- ^ "Scopus preview - Scopus - Document details". Archived from the original on 2013-02-01.
- ^ "Killer Whale vs. Sea Lions". YouTube. Archived from the original on 2021-12-15. Retrieved 2012-10-21.
- ^ Claudia Jordan (2006-04-03). "Object manipulation and tool-use in captive pygmy chimpanzees (Pan paniscus)". Journal of Human Evolution. 11: 35–39. doi:10.1016/s0047-2484(82)80029-8.
- ^ Hopkins, W. D.; Bard, K. A.; Jones, A.; Bales, S. L. (1993). "Chimpanzee Hand Preference in Throwing and Infant Cradling: Implications for the Origin of Human Handedness". Current Anthropology. 34 (5): 786–790. doi:10.1086/204224. JSTOR 2744291. S2CID 56032181.
- ^ Nakamichi, Masayuki (1999). "Primates, Volume 40, Number 3". Primates. 40 (3). SpringerLink: 487–498. doi:10.1007/BF02557584. S2CID 41542232.
- ^ Biruté M.F. Galdikas (2006-04-03). "Orang-utan tool-use at Tanjung Puting Reserve, Central Indonesian Borneo (Kalimantan Tengah)". Journal of Human Evolution. 11: 19–33. doi:10.1016/s0047-2484(82)80028-6.
- ^ Westergaard, G. C.; Suomi, S. J. (1994). "Human Evolution, Volume 9, Number 4". Human Evolution. 9 (4). SpringerLink: 323–329. doi:10.1007/BF02435518. S2CID 84810150.
- ^ Cunningham, Clare L.; Anderson, James R.; Mootnick, Alan R. (2006). "Object manipulation to obtain a food reward in hoolock gibbons, Bunopithecus hoolock". Animal Behaviour. 71 (3): 621–629. doi:10.1016/j.anbehav.2005.05.013. S2CID 53160226.
- ^ Maple, Terry (1975). "Aggressive Object Displays of Captive Baboons". Journal of Mammalogy. 56 (4): 949–950. doi:10.2307/1379674. JSTOR 1379674. PMID 1237529.
- ^ Leca, JB; Nahallage, CA; Gunst, N; Huffman, MA (2008). "Stone-throwing by Japanese macaques: form and functional aspects of a group-specific behavioral tradition". Journal of Human Evolution. 55 (6): 989–998. doi:10.1016/j.jhevol.2008.06.004. PMID 18715623.
- ^ Wood, Justin N.; Glynn, David D.; Hauser, Marc D. (2007-08-22). "The uniquely human capacity to throw evolved from a non-throwing primate: an evolutionary dissociation between action and perception". Biology Letters. 3 (4): 360–365. doi:10.1098/rsbl.2007.0107. PMC 2390659. PMID 17550878.
- ^ "Chimpanzee planned stone attacks on zoo visitors - Science, News - the Independent". Independent.co.uk. Archived from the original on April 18, 2009. Retrieved May 5, 2010.
- ^ Herrel, A.; Deban, S.M.; Schaerlaeken, V.; Timmermans, J.-P.; Adriaens, D. (2009). "Are morphological specializations of the hyolingual system in chameleons and salamanders tuned to demands on performance?". Physiological and Biochemical Zoology. 82 (1): 29–39. doi:10.1086/589950. PMID 19007314. S2CID 16892331.
- ^ de Groot, J.H. & van Leeuwen, J.L. (2004). "Evidence for an elastic projection mechanism in the chameleon tongue". Proceedings of the Royal Society of London B. 271 (1540): 761–770. doi:10.1098/rspb.2003.2637. PMC 1691657. PMID 15209111.
- ^ Deban, S.M.; O'Reilly, J.C.; Dicke, U.; van Leeuwen, J.L. (2007). "Extremely high-power tongue projection in plethodontid salamanders". Journal of Experimental Biology. 210 (4): 655–667. doi:10.1242/jeb.02664. PMID 17267651.
- ^ Herrel, A.; Meyers, J.J.; Timmermans, J.-P.; Nishikawa, K.C. (2002). "Supercontracting muscle: producing tension over extreme muscle lengths". Journal of Experimental Biology. 205 (Pt 15): 2167–2173. doi:10.1242/jeb.205.15.2167. PMID 12110650.
- ^ Maurice Burton & Robert Burton (1970). The International Wildlife Encyclopedia, Volume 1. Marshall Cavendish. p. 2366.
- ^ "sandbox tree | plant". Retrieved 2016-08-31.
- ^ "Mosses use explosive cannons and mushroom clouds to spread their spores | Not Exactly Rocket Science | Discover Magazine". Blogs.discovermagazine.com. 2010-07-22. Retrieved 2012-10-21.
- ^ "BBC Nature - Hat thrower fungus videos, news and facts". Bbc.co.uk. 1970-01-01. Retrieved 2012-10-21.
- ^ Walker L (1927). "Development and mechanism of discharge in Sphaerobolus iowensis and S. stellatus Tode". J. Eli. Mitch. Sci. Soc. 42: 151–178.
- ^ S. M. Douglas. "Sphaerobolus spp.—The Artillery Fungus" (PDF). The Connecticut Agricultural Experiment Station. Retrieved 2008-11-27.
- ^ Nawaz M (1967). "Phototropism in Sphaerobolus". Biologia. 13: 5–14.
External links
- Nature's Marksmen - a video showing projectile use by archerfish and velvet worms