[3] The last sighting of a single male golden toad was on 15 May 1989, and it has since been classified as extinct by the International Union for Conservation of Nature (IUCN).

Males were orange and sometimes slightly mottled on the belly, while females showed a greater variety of colors, including black, yellow, red, green, and white; both sexes had smooth skin.

They would emerge in late March through April to mate for the first few weeks in rainwater pools amongst tree roots, where they also laid their eggs.

[13] For a few weeks in April, after the dry season ended and the forest became wetter, males would gather in large numbers near ground puddles and wait for the females.

[16] Males outnumbered females, in some years by as many as ten to one, a situation that often led bachelors to attack amplectant pairs and form what has been described as a "writhing masses of toad balls".

In her book, In Search of the Golden Frog, she described it as "one of the most incredible sights I've ever seen", and said they looked like "statues, dazzling jewels on the forest floor".

On April 15, 1987, Crump recorded in her field diary that she counted 133 toads mating in one "kitchen sink-sized pool" that she was observing.

Five days later, she witnessed the pools in the area drying, which she attributed to the effects of the El Niño-Southern Oscillation, "leaving behind desiccated eggs already covered in mold".

[16] In the period between its discovery and disappearance, the golden toad was commonly featured on posters promoting the biodiversity of Costa Rica.

[1] In August 2010 a search organised by the Amphibian Specialist Group of the International Union for Conservation of Nature, aiming to verify the status of various species of frogs thought to be extinct in the wild, failed to find evidence of surviving specimens.

[22] Since records of golden toads were consistently collected, their rapid disappearance was well documented, yet the causes remain poorly understood.

[19] The IUCN has given numerous possible reasons for the species' extinction, including its "restricted range, global warming, chytridiomycosis and airborne pollution".

[1] Jennifer Neville examined the different hypotheses explaining the extinction in her article "The Case of the Golden Toad: Weather Patterns Lead to Decline", and concluded that Crump's El Niño hypothesis is "clearly supported" by the available data.

[18] Another theory is that the anuran water loss from dry conditions helped cause high mortality rates among adults, although this point is hotly contested.

[4] In 1991, ML Crump, FR Hensley, and KL Clark attempted to understand whether the decline of the golden toad in Costa Rica meant that the species was underground or extinct.

To test the hypothesis a study was conducted using oxygen isotope measurements from trees identifying data spanning the years of 1900–2002.

In Atelopus, another genus found in the tropical Americas, an estimated 67% of the ~110 species of have become extinct or endangered, and the pathogenic chytrid fungus Batrachochytrium dendrobatidis, which causes chytridiomycosis, is implicated in this regard.

An earlier study by Pounds and Crump based on the El Niño event in 1986–1987[29] had concluded, after observing the dry conditions from higher temperatures and lower seasonal rainfall, that this could potentially have caused the extinction.

These strong positive anomalies are indicators of periods of lower precipitation and temperature differences of greater than 1 degree Celsius.

"[25] Taking the results and recent findings that tie the golden toad's population crash to disease, the authors concluded that climate-driven epidemics are an immediate threat to biodiversity.

It is possible that the warmer climate made the species more susceptible to disease, or those warm years could have favored Batrachochytrium directly.

There is a possibility that the B. dendrobatidis was too damaged to detect, but even with this data, there is not enough to prove that climate change had a significant enough impact on the growth and spreading of the deadly fungus.