Characteristics edit
Wild alligators range from long and slender to short and robust, possibly due to variations in factors like growth rate, diet and climate. Alligators have broad snouts, especially in captive individuals. When the jaws are closed, the edge of the upper jaws covers the lower teeth which fit into the jaws' depressions. Like the spectacled caiman, this species has a bony nasal ridge, though it is less prominent.[1] The teeth number from 74–84.[1] Dorsally, adult alligators may be olive, brown, gray or black in color while their undersides are cream colored.[2]
Some alligators are missing an inhibited gene for melanin, which makes them albino. These alligators are extremely rare and almost impossible to find in the wild. They could survive only in captivity as they are very vulnerable to the sun and predators.[3]
Size edit
The American alligator is a fairly large species of crocodilian, with males reaching an average maximum size of 4.6 m (15 ft) in length, weighing up to 453 kg (999 lb), while females grow to a maximum of 3 m (9.8 ft).[4][5] Occasionally, a large, old male may measure longer.[6][7] There have been reports during the 19th and 20th centuries of larger males reaching 5 to 6 m (16 to 20 ft).[1] The largest reported size was a male killed in 1890 on Marsh Island, Louisiana and reportedly measured at 5.8 m (19 ft) in length but no voucher specimen was available since the alligator was left on a muddy bank after having been taped due to having been too massive to relocate.[7] If the size of this animal was correct, it would have weighed around 1,000 kg (2,200 lb). The largest alligator shot in Florida was 5.31 m (17.4 ft), as reported by the Everglades National Park.[8][9] However on average, American alligators do not reach such extreme sizes. In males, size averages at around 3.4 to 4 m (11 to 13 ft) in length, weighing slightly in excess of 227 kg (500 lb), while in smaller females, it averages 2.7 m (8.9 ft), weighing slightly in excess of 91 kg (201 lb).[10] Weight varies depending on length, age, health, season and available food sources. Similar to other reptiles, American alligators from the northern end of their range, such as southern Arkansas, Alabama, and northern North Carolina, tend to grow to smaller sizes. The largest alligator caught in Alabama was only 3.86 m (12.7 ft) in length, weighing 306.2 kg (675 lb).[11]
Physiology edit
When on land, the alligator moves either by sprawling or walking, the latter involving the reptile lifting its belly off the ground. The sprawling of alligators and other crocodilians is not identical to the sprawling of salamanders and lizards, being similar to walking. Thus the two forms of territorial locomotion can be termed the "low walk" and the "high walk". Unlike most another land vertebrates, alligators increase their speed through the distal rather than proximal ends of their limbs.[12] In the water, alligators swim like fish; moving their pelvic regions and tails from side to side.[13] American alligators held the record as having the strongest laboratory-measured bite of any living animal, measured at up to 9,452 newtons (2,125 lbf) in laboratory conditions. It should be noted that this experiment had not at the time of the paper published been replicated in any other crocodilians and the same laboratory was able to measure a greater bite force in saltwater crocodiles.[14][15] During respiration, airflow is unidirectional; looping through the lungs during inhalation and exhalation.[16]
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- ^ a b c "Crocodilian Species—American Alligator (Alligator mississippiensis)". Flmnh.ufl.edu. Retrieved 2008-10-14.
- ^ "American Alligator: Species Profile". US National Parks Service. Retrieved August 14, 2012.
- ^ "Zoo keeps albino alligator in the dark". NBC News.com. May 11, 2007. Retrieved August 15, 2012.
- ^ [1]. Animals.nationalgeographic.com
- ^ [2]. Philadelphia Zoo. Retrieved on 2013-04-13.
- ^ Crocodiles and Alligators edited by S Charles A. Ross & Stephen Garnett. Checkmark Books (1989), ISBN 978-0816021741.
- ^ a b Wood, Gerald (1983). The Guinness Book of Animal Facts and Feats. ISBN 978-0-85112-235-9.
- ^ [3]. Everglades.national-park.com
- ^ [4]. FloridaAdventuring.com
- ^ "Gator factsheet" (PDF). Savannah River Ecology Laboratory. Retrieved August 14, 2012.
- ^ [5]
- ^ Reilly, S. M.; Elias, J. A. (1998). "Locomotion in alligator mississippiensis: kinematic effects of speed and posture and their relevance to the sprawling-to-erect paradigm" (PDF). The Journal of Experimental Biology. 201 (18): 2559–74. PMID 9716509.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Fish, F. E. (1984). "Kinematics of undulatory swimming in the American alligator" (PDF). Copeia. 1984 (4): 839–43. doi:10.2307/1445326.
- ^ Erickson, Gregory M.; Lappin, A. Kristopher; Vliet, Kent A. (2003). "The ontogeny of bite-force performance in American alligator (Alligator mississippiensis)" (PDF). Journal of Zoology. 260 (3): 317–327. doi:10.1017/S0952836903003819.
- ^ [6]
- ^ Farmer, C. G. (2010). "Unidirectional airflow in the lungs of alligators". Science. 327 (5963): 338–340. doi:10.1126/science.1180219. PMID 20075253.
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