Animal Diversity Web

Ge­o­graphic Range

Cur­rently, Chi­nese al­li­ga­tors re­side nat­u­rally within the lower Yangtze River basin, lo­cated along the cen­tral Pa­cific coast of China. His­tor­i­cally, when pop­u­la­tions were more nu­mer­ous, they spread over much greater areas. Lit­er­a­ture cites this species as early as the third cen­tury A.D., in­clud­ing ref­er­ence that it lived in other areas of China and pos­si­bly even Korea. It was es­ti­mated in 1998 that the ge­o­graphic range of Chi­nese al­li­ga­tors had de­creased by over ninety per­cent in the past twenty years. (Mertz, 2003; Behler and Behler, 1998; Neill, 1971)

• Biogeographic Regions
• oriental
  • native

Habi­tat

Chi­nese al­li­ga­tors live in a sub­trop­i­cal, tem­per­ate re­gion. They live in wet­lands and swamps, ponds, lakes, as well as fresh­wa­ter rivers and streams. (Mertz, 2003)

• Habitat Regions
• temperate
• tropical
• terrestrial
• freshwater

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• temporary pools

• Wetlands
• marsh

• Other Habitat Features
• riparian

Phys­i­cal De­scrip­tion

Chi­nese al­li­ga­tors are yel­low­ish gray in color with pro­nounced black spot­ting of the lower jaw. They have four short claw-tipped limbs with five par­tially webbed toes on each limb. Their long, thick tail pro­vides a pri­mary lo­co­mo­tive force in the water. They have os­teo­derms, der­mal bone lying over the epi­der­mis used as armor, cov­er­ing both the back and un­der­side of the body. Un­like croc­o­diles, their fourth mandibu­lar teeth in the lower jaw lie in sock­ets in the upper jaw, and are un­ex­posed when the jaws are closed. Also char­ac­ter­is­tic of this species is the up­turned snout. Sim­i­lar to caimans, but un­like their clos­est rel­a­tives, Amer­i­can al­li­ga­tors (Al­li­ga­tor mis­sis­sip­pi­en­sis), Chi­nese al­li­ga­tors have a bony plate in the upper eye­lid. (Mertz, 2003; "Chi­nese Al­li­ga­tor", 1994)

Ju­ve­niles ap­pear very sim­i­lar to adults with the ex­cep­tion that ju­ve­niles have dis­tinc­tive yel­low bands along their bod­ies. They have an av­er­age of five bands on their bod­ies, and eight on their tails. As adults ma­ture, their col­or­ing be­comes less and less con­spic­u­ous. (Neill, 1971)

Males have been recorded up to 2.2 m long from snout to tail, al­though the av­er­age size is 1.5 m. Fe­males have been recorded up to 1.7 m, av­er­ag­ing around 1.4 m. (Mertz, 2003)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger

• Range length

  1.4 to 2.2 m

  4.59 to 7.22 ft

• Average length

  1.4 - 1.5 m

  ft

De­vel­op­ment

Young al­li­ga­tors begin de­vel­op­ment as hard-shelled eggs laid in a nest. Sex is de­ter­mined by the tem­per­a­ture of the egg dur­ing in­cu­ba­tion. Fe­males are pro­duced at lower in­cu­ba­tion tem­per­a­tures of below 28°C, while males are pro­duced at higher tem­per­a­tures of above 33°C. For this rea­son nests can pro­duce a ma­jor­ity of one sex over the other based on the tem­per­a­ture of the nest. Sim­i­larly, nests can pro­duce dif­fer­ent sexes based upon what layer, how deep, or how shal­low the egg was buried. The crit­i­cal tem­per­a­ture for Chi­nese al­li­ga­tors, pro­duc­ing an even num­ber of males and fe­males is 31°C. The in­cu­ba­tion pe­riod is ap­prox­i­mately sev­enty days. Hatch­lings weigh about 30 g and av­er­age slightly over 21 cm long. ("Croc­o­diles", 2002; Alder­ton, 1991; Ther­b­jarnar­son, et al., 2001)

Rapid growth oc­curs for the first five years of life. Re­pro­duc­tive ma­tu­rity in Chi­nese al­li­ga­tors is reached after five to seven years. In cap­tiv­ity they are known to re­pro­duce into their fifties. (Mertz, 2003; Alder­ton, 1991)

• Development - Life Cycle
• temperature sex determination

Re­pro­duc­tion

The mat­ing sea­son oc­curs an­nu­ally in June, a month after the rainy sea­son has begun. Both males and fe­males will vo­cal­ize with a bel­low or roar to com­mu­ni­cate their lo­ca­tion and find a mate. An­other fea­ture used in mat­ing shared by both males and fe­males is a musk gland under the lower jaw that pro­duces an at­trac­tive scent. Male al­li­ga­tors are polyg­y­nous, a male may fer­til­ize sev­eral fe­males in one mat­ing sea­son. Fe­males are known to have only one mate each sea­son. ("Al­li­ga­tor", 1980; "Croc­o­diles", 2002; Alder­ton, 1991)

• Mating System
• polygynous

In July fe­males make a mound nest out of sur­round­ing veg­e­ta­tion and mud on land sur­round­ing lakes or rivers. Fe­males will use co­or­di­nated move­ments of the front and hind limbs to form a pile in the cen­ter just under 1 m high. Nests are often lo­cated near a bur­row so that the mother can at­tend to her nest dur­ing in­cu­ba­tion. She will lay an av­er­age of ten to forty eggs in a de­pres­sion on top of the mound, and then cover them with more veg­e­ta­tion. Chi­nese al­li­ga­tors reach sex­ual ma­tu­rity in 5 to 7 years. ("Al­li­ga­tor", 1980; "Croc­o­dil­ians", 2002; Alder­ton, 1991; "Al­li­ga­tor", 1980; "Croc­o­dil­ians", 2002; Alder­ton, 1991)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• oviparous

• Breeding interval

  Chinese alligators breed once a year.

• Breeding season

  Mating occurs in June, followed by egg-laying in mid-July. The female guards the nest for the 70 day incubation period until the hatchlings emerge in September.

• Range number of offspring

  10 to 40

• Range age at sexual or reproductive maturity (female)

  5 to 7 years

• Range age at sexual or reproductive maturity (male)

  5 to 7 years

Fe­males guard the nest from sur­round­ing preda­tors, vis­it­ing it fre­quently, whereas males have no parental in­volve­ment. Hatch­lings will emerge in Sep­tem­ber. Re­spond­ing to their vo­cal­iza­tions, fe­males will re­move any de­bris cov­er­ing the nest, and bring their off­spring to the water. They may even help the hatch­lings break out of their egg shells by slowly rolling them around in the mouth and lightly crack­ing the shell by press­ing the egg be­tween the roof of the mouth and tongue. Fe­males are known to live with their young through the first win­ter, but lit­tle else is known about the spe­cific in­ter­ac­tions be­tween adult Chi­nese al­li­ga­tors and their young. (Mertz, 2003; "Croc­o­diles", 2002; "Croc­o­dil­ians", 2002)

• Parental Investment
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • protecting
    • female

Lifes­pan/Longevity

Both male and fe­male Chi­nese al­li­ga­tors, once thought to live only into their 50's, have now reached into their 70's in cap­tiv­ity. (Mertz, 2003)

• Average lifespan
  Status: wild

  50 years

• Average lifespan
  Status: captivity

  70 years

• Average lifespan
  Status: captivity

  38.1 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Status: captivity

  27.1 years

  Max Planck Institute for Demographic Research

Be­hav­ior

Chi­nese al­li­ga­tors are dor­mant from late fall into early spring, when tem­per­a­tures are cool. They cre­ate bur­rows on the banks of wet­lands that are ap­prox­i­mately 1 m deep, 0.3 m in di­am­e­ter and 1.5 m long. Bur­rows are used through­out the year, but pri­mar­ily in the win­ter. These bur­rows can also be very elab­o­rate, and may house more than one al­li­ga­tor. Once they emerge from their bur­rows in April, they spend time bask­ing in the sun to raise their body tem­per­a­ture, as they are ec­totherms and can­not cre­ate their own heat. Once their body tem­per­a­ture has nor­mal­ized, they re­turn to their nor­mal noc­tur­nal ways. They are aquatic an­i­mals, and can also use the water to ther­moreg­u­late by stay­ing in the upper water columns heated by the sun, or mov­ing to shaded wa­ters to cool off. Mat­ing rit­u­als occur in the spring. Chi­nese al­li­ga­tors are thought to be the most docile of the croc­o­dil­ians. (Mertz, 2003; Alder­ton, 1991; Neill, 1971)

• Key Behaviors
• natatorial
• nocturnal
• motile
• sedentary
• hibernation
• solitary
• territorial
• dominance hierarchies

Com­mu­ni­ca­tion and Per­cep­tion

Chi­nese al­li­ga­tors use a bel­low­ing sound, vo­cal­ized by both males and fe­males, as a way to com­mu­ni­cate lo­ca­tion. Al­though this is used much more fre­quently dur­ing the mat­ing sea­son, it is also used at other times through­out the year. Both males and fe­males use body lan­guage to com­mu­ni­cate. One ex­am­ple of this is slap­ping the water with their lower jaws. An­other is snap­ping their jaws as a warn­ing sig­nal. Dur­ing mat­ing, the male may cre­ate sub­audi­ble vi­bra­tions in the water to at­tract a mate. Also in mat­ing, the fe­male may rub up against the male to in­di­cate she is ready to mate. (Mertz, 2003; "Croc­o­diles", 2002; Alder­ton, 1991)

• Communication Channels
• tactile
• acoustic
• chemical

• Other Communication Modes
• scent marks
• vibrations

• Perception Channels
• visual
• tactile
• acoustic
• vibrations
• chemical

Food Habits

Chi­nese al­li­ga­tors are noc­tur­nal, car­niv­o­rous preda­tors. Adults prey mostly on fish, snails, clams, as well as small mam­mals and wa­ter­fowl. There is some spec­u­la­tion that they may prey on tur­tles as well. Younger al­li­ga­tors will eat in­sects and other small in­ver­te­brates (Mertz, 2003; Mertz, 2003)

• Primary Diet
• carnivore
  • eats terrestrial vertebrates
  • piscivore
  • insectivore
  • eats non-insect arthropods
  • molluscivore

• Animal Foods
• birds
• mammals
• reptiles
• fish
• insects
• mollusks

Pre­da­tion

Adult Chi­nese al­li­ga­tors have only one preda­tor, hu­mans. Al­though pro­tected by law, they are still in dan­ger of hunt­ing by hu­mans. Al­li­ga­tors are hunted for their meat and in­ter­nal or­gans for al­ter­na­tive med­i­cine use and also food. They are not hunted for skin be­cause the skin on their bel­lies, cus­tom­ar­ily used as a tex­tile in other croc­o­dil­ian species, is cov­ered in os­teo­derms and there­fore in­ad­e­quate. (Alder­ton, 1991)

Ju­ve­nile al­li­ga­tors and eggs are most at risk due to their size. De­spite the pro­tec­tion of the mother al­li­ga­tor, the young ones are at a high risk of pre­da­tion by other larger an­i­mals. These preda­tors could be any­thing from other adult al­li­ga­tors to large birds and fish. ("Al­li­ga­tor", 1980)

• Anti-predator Adaptations
• cryptic

• Known Predators

  • large birds (Aves)
  • alligators (Alligator sinensis)
  • large fish (Actinopterygii)
  • humans (Homo sapiens)

Ecosys­tem Roles

Due to their scarcity, Chi­nese al­li­ga­tors cur­rently have lit­tle to no im­pact on the ecosys­tems in which they live. His­tor­i­cally they were im­por­tant aquatic preda­tors. (Mertz, 2003)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

His­tor­i­cally, hu­mans used parts of Chi­nese al­li­ga­tors for al­ter­na­tive med­i­cine, es­pe­cially to treat af­flic­tions of the gall blad­der. They were also used as a food source. Be­cause there are so few in the world today, they have lit­tle to no im­pact on hu­mans. (Alder­ton, 1991)

• Positive Impacts
• food
• ecotourism
• source of medicine or drug

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Be­cause of their docile na­ture, and lim­ited abun­dance in the world, the pos­si­bil­ity of at­tacks by Chi­nese al­li­ga­tors is highly un­likely. There have never been any at­tacks recorded by Chi­nese al­li­ga­tors. De­spite this in­for­ma­tion, if pro­voked, it is pos­si­ble that an al­li­ga­tor would at­tack, and should be con­sid­ered po­ten­tially dan­ger­ous. (Alder­ton, 1991; Alder­ton, 1991)

• Negative Impacts
• injures humans
  • bites or stings
• crop pest

Con­ser­va­tion Sta­tus

Chi­nese al­li­ga­tors are a crit­i­cally en­dan­gered species. They are cur­rently on the IUCN Red List of threat­ened species, and have been since 1986. Pre­vi­ously, they were listed in the IUCN Am­phibia-Rep­tilia Red Data Book. Habi­tat de­struc­tion is iden­ti­fied as the pri­mary cause for their de­cline. Other fac­tors in­clude pol­lu­tion and human in­tol­er­ance and pre­da­tion. Al­though they are fairly suc­cess­ful in cap­tiv­ity world­wide, there are thought to be less than 150 in­di­vid­u­als alive in the wild today. Laws have been set in place to pro­tect these an­i­mals, and luck­ily the small re­gion in which they live is some­what iso­lated. The Yangtze River basin floods every year, pre­vent­ing its use as farm land and from per­ma­nent human res­i­dency. Al­though there has been much suc­cess in breed­ing Chi­nese al­li­ga­tors in cap­tiv­ity, lit­tle ef­fort is being made to re­lease cap­tive bred in­di­vid­u­als to re­plen­ish the wild pop­u­la­tion. (Mertz, 2003; Behler and Behler, 1998; Pope, 1955)

• IUCN Red List

  Critically Endangered
  More information

• IUCN Red List

  Critically Endangered
  More information

• US Federal List

  Endangered

• CITES

  Appendix I

Other Com­ments

Other com­mon names: Eng­lish: Chi­nese al­li­ga­tor, Yangtze al­li­ga­tor; Chi­nese: Tou lung, Yow lung, T’o; French: al­li­ga­tor de Chine; Ger­man: China-al­li­ga­tor; Span­ish: al­li­ga­tor de China. (Mertz, 2003)

Con­trib­u­tors

Tanya Dewey (ed­i­tor), An­i­mal Di­ver­sity Web.

Lau­ren Groppi (au­thor), Kala­ma­zoo Col­lege, Ann Fraser (ed­i­tor, in­struc­tor), Kala­ma­zoo Col­lege.

Ref­er­ences

1980. Al­li­ga­tor. M Bur­ton, R Bur­ton, eds. The New In­ter­na­tional Wildlife En­cy­clo­pe­dia, Vol. 1. Mil­wau­kee: Pur­nell Ref­er­ence Books.

1994. Chi­nese Al­li­ga­tor. Pp. 782-783 in M Emanoil, ed. En­cy­clo­pe­dia of En­dan­gered Species. De­troit: Gale Re­search.

2002. Croc­o­diles. Pp. 295-299 in C Hoagstrom, ed. Mag­ill's En­cy­clo­pe­dia of Sci­ence: An­i­mal Life, Vol. 1. Pasadena: Salem Press.

2002. Croc­o­dil­ians. Pp. 212-221 in T Hal­l­i­day, K Adler, eds. Fire­fly En­cy­clo­pe­dia of Rep­tiles and Am­phib­ians. Buf­falo: Fire­fly Books.

Alder­ton, D. 1991. Croc­o­diles and Al­li­ga­tors of the World. New York: Facts on File.

Behler, J., D. Behler. 1998. Al­li­ga­tors and Croc­o­diles. Still­wa­ter: Voy­ager Press.

Mertz, L. 2003. Al­li­ga­tors and caimans. Pp. 171-176 in M Hutchins, J Mur­phy, N Schlager, eds. Grizmek's An­i­mal Life En­cy­clo­pe­dia, Vol. 7, 2 Edi­tion. Farm­ing­ton Hills, Michi­gan, USA: Gale Group.

Neill, W. 1971. The Last of the Rul­ing Rep­tiles: Al­li­ga­tors, Croc­o­diles, and Their Kin. New York: Co­lum­bia Uni­ver­sity Press.

Pope, C. 1955. The Rep­tile World: A Nat­ural His­tory of Snakes, Liz­zards, Tur­tles, and Croc­o­dil­ians. New York: Al­fred A Knopf.

Ther­b­jarnar­son, J., X. Wang, L. He. 2001. Re­pro­duc­tive ecol­ogy of the Chi­nese al­li­ga­tor (Al­li­ga­tor sinen­sis) and im­pli­ca­tions for con­ser­va­tion. Jour­nal of Her­petol­ogy, 35: 553-558.