Incilius periglenes

Ge­o­graphic Range

The golden toad once oc­cu­pied a small area of 4 km2 of elfin cloud for­est on the Cordillera de Tila­ran in north­ern Costa Rica. This area is now known as the Mon­teverde Cloud For­est Pre­serve (Pounds, 1996).

Habi­tat

The golden toad oc­cu­pies a wet, mon­tane area of the for­est in north­ern Costa Rica. The el­e­va­tion of this habi­tat ranges from 2000 -- 2100 me­ters (Ja­cob­son, 1991).

Phys­i­cal De­scrip­tion

The golden toad is an ex­treme ex­am­ple of a sex­u­ally di­mor­phic am­phib­ian. The males pos­sess a very strik­ing or­ange col­oration. The fe­males are black with scar­let blotches edged in yel­low. The fe­males range in length from 42 -- 56 mm while the males are 39 -- 48 mm. The strik­ing phys­i­cal dif­fer­ences be­tween male and fe­male can­not be de­ter­mined until adult­hood. Ju­ve­niles tend to be un­sex­able since they carry sim­i­lar char­ac­ter­is­tics and body size (Ja­cob­son, 1991).

De­vel­op­ment

Re­pro­duc­tion

The golden toad is an ex­plo­sive breeder dur­ing the months of April through June in which there is a heavy rainy sea­son. The toads gather in enor­mous num­bers around small, tem­po­rary pools and other wa­ter-filled de­pres­sions that are lo­cated within the for­est. Dur­ing this time, the com­pe­ti­tion be­tween males for fe­males is quite fierce. The males gen­er­ally out­num­ber the fe­males by an 8:1 ratio. It is at this time that males will mate with al­most any mov­ing ob­ject and mo­lest other pairs that were in am­plexus. Males also ex­hib­ited a be­hav­ior known as "toad balls" in which 4-10 males would clasp each other. How­ever, a suc­cess­ful mat­ing would pro­duce around 200 to 400 eggs. The large di­am­e­ter of the eggs is around 3.0 mm (Ja­cob­son, 1991) The lar­val forms are all un­sex­able be­cause of the same size and color. They re­main in the pool and take up to 5 weeks to meta­mor­phose (Hard­ing, 1993).

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)

Be­hav­ior

As with food habits, the be­hav­ior of the golden toad is poorly known. One clue to their ex­is­tence is the shared be­hav­ioral and eco­log­i­cal char­ac­ter­is­tics with Bufo holdridgei. This small toad is dis­trib­uted in the same area as In­cil­ius periglenes. The two species also ex­hibit the same re­pro­duc­tive be­hav­ior such as in­tense male be­hav­iors, small clutch size, and large eggs. It has been sug­gested that these two species ex­hibit sim­i­lar phy­lo­ge­netic his­tory in order to live in the same harsh habi­tat. Bufo holdridgei were re­ported to live un­der­ground dur­ing dif­fer­ent sea­sons. This could be a pos­si­ble clue to the be­hav­ior of the In­cil­ius periglenes (Ja­cob­son, 1991).

Food Habits

There are lit­tle in­for­ma­tion re­gard­ing this species' food habits since they have been pri­mar­ily ob­served dur­ing the breed­ing sea­son and live very se­cre­tive lives within the forests. Judg­ing by size, many would agree that they feed on smaller in­ver­te­brates (Ja­cob­son, 1991).

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

The golden toad is most im­por­tant to the sci­en­tific world. They give us the op­por­tu­nity to study rare and beau­ti­ful species up close and per­sonal. They also strengthen the sci­en­tific com­mu­nity's res­o­lu­tion to find out why am­phib­ians are de­creas­ing glob­ally.

Con­ser­va­tion Sta­tus

Un­for­tu­nately, the golden toad is a re­pro­duc­tively vul­ner­a­ble species. They are clas­si­fied as hav­ing a "nar­row win­dow of time" in order to breed. Dur­ing the rainy sea­son, just the right amount of rain must fall in order to have a suc­cess­ful year. If the rains are too heavy, the larva might flow onto the for­est floor and be stranded. How­ever, if the rains are too light, the lar­vae will des­ic­cate. Dur­ing 1987, there was a major pop­u­la­tion crash in the golden toads. Due to er­ratic weather, the pools dried up be­fore the larva had ma­tured. Out of po­ten­tial 30,000 toads, only 29 had sur­vived. Since then, only a few scat­tered in­di­vid­u­als had been found up until 1991 when no toads were re­ported. Find­ing out why this hap­pened is a mys­tery. Some say that global warm­ing caused the er­ratic weather that de­stroyed the re­pro­duc­tive ef­forts of the golden toad. Oth­ers say it was de­for­esta­tion around the pre­serve that killed many of the adults when they left the re­pro­duc­tive area. Fi­nally, some say that the toads are sim­ply hid­ing out until the con­di­tions are right to re­pro­duce. Over­all, no one can say for sure and only time will tell. Until then, their re­pro­duc­tive area is still pro­tected if and when they re­turn (Hard­ing, 1993).

Other Com­ments

The golden toad ap­pears to use vi­sual rather than vocal recog­ni­tion used by most other toads. It only gives two types of calls, the re­lease call and an­other call given by a male in am­plexus. The fre­quency and du­ra­tion of these calls could only be heard over a few me­ters. The calls could not even be heard on rainy days. It is sug­gested that the bright col­oration and di­ur­nal ac­tiv­i­ties of this toad fa­cil­i­tated vi­sual rather than acousti­cal iden­ti­fi­ca­tion (Ja­cob­son, 1991).

Con­trib­u­tors

Jason De­G­root (au­thor), Michi­gan State Uni­ver­sity, James Hard­ing (ed­i­tor), Michi­gan State Uni­ver­sity.

Glossary

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

Ref­er­ences

Hard­ing, K. 1993. Con­ser­va­tion and the Case of the Golden Toad. British Her­peto­log­i­cal Bul­letin, 44: 31-34.

Ja­cob­son, S. 1991. Re­pro­duc­tive Ecol­ogy of the En­dan­gered Golden Toad (Bufo periglenes). Jour­nal of Her­petol­ogy, 25: 321-326.

Pounds, A. 1996. Con­ser­va­tion of the Golden Toad: A Brief His­tory. British Her­peto­log­i­cal Bul­letin, 55: 5-7.