Animal Diversity Web

Ge­o­graphic Range

Xeno­pus lae­vis oc­curs nat­u­rally in south­ern Africa. There are sub­stan­tial in­tro­duced pop­u­la­tions in Cal­i­for­nia, Chile, Great Britain, and prob­a­bly many other lo­ca­tions around the world. (Nieukoop and Faber, 1994)

• Biogeographic Regions
• nearctic
  • introduced
• palearctic
  • introduced
• ethiopian
  • native

Habi­tat

Xeno­pus lae­vis lives in warm, stag­nant grass­land ponds as well as in streams in arid and semi-arid re­gions. The ponds are usu­ally de­void of any higher plant veg­e­ta­tion, and cov­ered in green algae. Xeno­pus lae­vis can tol­er­ate wide vari­a­tion in water pH, but the pres­ence of metal ions proves toxic. It thrives in tem­per­a­tures from 60 to 80 de­grees Fahren­heit. It is al­most to­tally aquatic, only leav­ing the water when forced to mi­grate.

(Nieuwkoop and Faber, 1994; Beck, 1994; Ka­plan, 1995, Jack Crayon, per­sonal com­mu­ni­ca­tion)

• Habitat Regions
• temperate
• tropical
• freshwater

• Aquatic Biomes
• lakes and ponds
• rivers and streams

Phys­i­cal De­scrip­tion

Xeno­pus lae­vis has a unique mor­phol­ogy be­cause it lacks a tongue and a vis­i­ble ear. The body is flat­tened and head is wedge-shaped and smaller than the body. It has two small eyes found on the top of the head and no eye­lids. Its front limbs are small and are not webbed, and its hind legs are large and webbed and the three in­side toes on ei­ther foot have claws. It has smooth slip­pery skin which is mul­ti­col­ored on its back with blotches of olive gray or brown and gray, while the un­der­side is creamy white with a yel­low tinge. It has lat­eral lines along its back. Males weigh about 60 grams, are about 5 to 6 cen­time­ters long, and lack a vocal sac, which most male frogs have. Fe­males weigh about 200 grams, are about 10 to 12 cen­time­ters long, and have cloa­cal ex­ten­sions at the end of the ab­domen.

(Ka­plan, 1995; Chang 1998)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Sexual Dimorphism
• female larger

• Range mass

  60 to 200 g

  2.11 to 7.05 oz

• Range length

  5 to 12 cm

  1.97 to 4.72 in

• Average basal metabolic rate

  0.012 W

  AnAge

De­vel­op­ment

• Development - Life Cycle
• metamorphosis

Re­pro­duc­tion

Xeno­pus lae­vis is sex­u­ally ma­ture in 10 to 12 months. Mat­ing can take place dur­ing any time of the year, but is most com­mon in the spring, and can take place up to four times per year. Males vo­cal­ize dur­ing the evening to at­tract fe­males. Al­though the male lacks a vocal sac, it pro­duces a mat­ing call by rapid con­trac­tions of the in­trin­sic la­ryn­geal mus­cles. This mat­ing call sounds like al­ter­nat­ing long and short trills. After the fe­male hears this, she re­sponds with ei­ther an ac­cep­tance call (a rap­ping sound) or a re­jec­tion call (slow tick­ing sound). This is a nearly unique be­hav­ior in the an­i­mal world; rarely does a fe­male an­swer the males call. Mat­ing often takes place at night, when there are few dis­tur­bances. The male de­vel­ops mat­ing pads on the un­der­side of his fore­arms and hands. The mat­ing em­brace, am­plexus, is pelvic, whereas most frogs have ax­il­lary (front limb) am­plexus. The fe­male can re­lease hun­dreds of sticky eggs dur­ing the 3 to 4 hour event, which are typ­i­cally at­tached to plants or other an­chors, one or more at a time. The eggs grow into tad­poles, which fil­ter feed. The tad­pole meta­mor­phoses into a small froglet, with the tail being ab­sorbed into the body and sus­tain­ing its nu­tri­tional re­quire­ments dur­ing this pe­riod, which lasts about 4 to 5 days. The total change from egg to small frog takes about 6 to 8 weeks.

(Ka­plan, 1995; Beck, 1994; Chang, 1998; Kel­ley, 1998, Jack Crayon, per­sonal com­mu­ni­ca­tion)

• Key Reproductive Features
• iteroparous
• year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
  • external
• oviparous

• Breeding interval

  African clawed frogs can breed up to 4 times each year.

• Breeding season

  Mating can take place during any time of the year, but is most common in the spring.

• Range age at sexual or reproductive maturity (female)

  10 to 12 months

• Range age at sexual or reproductive maturity (male)

  10 to 12 months

Lifes­pan/Longevity

African clawed frogs can reach 15 to 16 years old in wild and feral pop­u­la­tions. Cap­tive an­i­mals have been known to live as long as 20 years.

• Range lifespan
  Status: wild

  16 (high) years

• Range lifespan
  Status: captivity

  20 (high) years

• Average lifespan
  Status: captivity

  8.8 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Status: captivity

  15.0 years

  Max Planck Institute for Demographic Research

Be­hav­ior

Xeno­pus lae­vis is a rather in­ac­tive crea­ture. It is in­cred­i­bly hardy and can live up to 15 years. At times the ponds that Xeno­pus lae­vis is found in dry up, com­pelling it, in the dry sea­son, to bur­row into the mud, leav­ing a tun­nel for air. It may lie dor­mant for up to a year. If the pond dries up in the rainy sea­son, Xeno­pus lae­vis may mi­grate long dis­tances to an­other pond, main­tain­ing hy­dra­tion by the rains. It is an adept swim­mer, swim­ming in all di­rec­tions with ease. It is barely able to hop, but it is able to crawl. It spends most of its time un­der­wa­ter and comes to sur­face to breathe. Res­pi­ra­tion is pre­dom­i­nantly through its well de­vel­oped lungs; there is lit­tle cu­ta­neous res­pi­ra­tion

(Ka­plan, 1995; Sim­monds 1985)

• Key Behaviors
• natatorial
• diurnal
• nocturnal
• motile
• sedentary
• solitary

Food Habits

Xeno­pus lae­vis is a scav­enger and eats liv­ing, dead, or dying arthro­pods and other pieces of or­ganic waste. It has a vo­ra­cious ap­petite and at­tacks any­thing that passes in front of it. It uses ex­tremely sen­si­tive fin­gers, an acute sense of smell, and its lat­eral line sys­tems to lo­cate food. Lat­eral line sys­tems, usu­ally found in fish, de­tect vi­bra­tions in the water. It uses a hy­obranchial pump to suck food into its mouth. The claws on its hind feet tear apart larger pieces of food. Tad­poles are ex­clu­sively fil­ter feed­ers

(Avila and Frye, 1977; Beck, 1994)

• Primary Diet
• carnivore
  • insectivore
  • scavenger

• Animal Foods
• insects
• aquatic or marine worms
• aquatic crustaceans

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Xeno­pus lae­vis has been used ex­ten­sively as a lab­o­ra­tory re­search an­i­mal, mostly in the field of ver­te­brate em­bry­ol­ogy be­cause fe­males are pro­lific egg lay­ers and em­bryos are trans­par­ent, mak­ing it easy to ob­serve the de­vel­op­ment of the em­bryo. Dur­ing the 1940's, fe­male X. lae­vis were in­jected with the urine of a woman. If the human was preg­nant, then the in­jected frog would start to pro­duce eggs. Xeno­pus lae­vis was the first ver­te­brate cloned in the lab­o­ra­tory. Ma­g­a­in­ins are a fam­ily of an­tibi­otics found in the skin of X. lae­vis, which heals wounded skin rapidly. Ma­g­a­inin is an an­tibi­otic, an­ti­fun­gal, an­tipar­a­sitic, and an­tivi­ral, prob­a­bly use­ful to the frog be­cause of the stag­nant, mi­crobe filled wa­ters in which it lives in. These ma­g­a­in­ins have been tested as an an­tibi­otic cream, which works just as well as an oral an­tibi­otic, but with­out the side ef­fects. Xeno­pus lae­vis is also used in lab be­cause it is very easy to care for, breed, and ob­serve.

• Positive Impacts
• source of medicine or drug
• research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Human ac­tiv­i­ties have trans­planted this African frog all over the globe, where some claim it is push­ing na­tive species out of their niche (Beck 1994). Oth­ers argue that there is no doc­u­mented case of this oc­cur­ring (Jack Crayon, pers. comm.)

Con­ser­va­tion Sta­tus

It is an in­va­sive species all over world be­cause it was used in human preg­nancy tests in the 1940's. When more ef­fec­tive means of preg­nancy tests were made avail­able, many X. lae­vis were re­leased all over the world.

• IUCN Red List

  Least Concern
  More information

Con­trib­u­tors

Nathan Gar­vey (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

Avila, Ver­non L. and Frye, Pa­tri­cia G. 1978. Feed­ing be­hav­ior of the African Clawed frog (Xeno­pus lae­vis Daudin):ef­fect of prey type. Jour­nal of Her­petol­ogy 12(3).

Beck, Alan. 1994. http://​gto.​nsca.​uiuc.​edu/​pingleto/​xenopus.​html

Ka­plan, Melissa. 1995. Nat­ural His­tory of the Up­land Clawed Frog. http://​www.​sonic.​net/​~melissk/xenopus.​html

Kel­ley, Darcy B. 1998. http://​www.​cc.​columbia.​edu/​cu/​biology/​faculty/​kelley.​html

Nieukoop, P.D and Faber, J. 1994. Nor­mal Table of Xeno­pus Lae­vis (Daudin). Gar­land Pub­lish­ing, Inc., New York and Lon­don

Sim­monds, Mark P. 1985. African Clawed toad sur­vey. British Her­peto­log­i­cal So­ci­ety Bul­letin No. 13.