What If Gone

Species → Devils Hole Pupfish

Devils Hole Pupfish

Cyprinodon diabolis

191 individuals (spring 2024 count)
Extinction risk Critically Endangered
Near-extinctionDesert environmentUmbrella species
Devils Hole Pupfish (Cyprinodon diabolis)
Photo: Olin Feuerbacher / USFWS, Wikimedia Commons (Public domain)

What if it disappeared?

Impact Major
Over 54 years

The entire species survives on a single 3.3 by 4.8 m rock shelf, in water at 34°C with very low oxygen content — spring counts fell to a historic low of 35 fish in 2013, before rebounding to 191 in 2024, the highest figure in more than twenty years.

Documented
Detail

National Park Service (Death Valley National Park) — comptages officiels de Devils Hole.

Before the 1990s, the spring count stood at around 200 fish; the decline that followed remains partly unexplained, as does the recent rebound. The entire species depends on a single aquifer, itself exposed to growing agricultural and urban groundwater pumping in the region as well as to climate warming — two threats bearing down on the one known habitat, with no fallback site existing in the wild.

Genomic analysis

58% of the Devils Hole pupfish genome consists of identical DNA segments — a level of inbreeding equivalent to four or five generations of sibling mating — and the species has lost 15 entire genes, five of them linked to adaptation to low-oxygen environments, precisely the setting it lives in.

Documented
Detail

Tian, D., Patton, A.H., Turner, B.J. et Martin, C.H. (2022). Severe inbreeding, increased mutation load and gene loss-of-function in the critically endangered Devils Hole pupfish. Proceedings of the Royal Society B, 289(1986), 20221561.

By sequencing the genomes of eight individuals, the authors document one of the most extreme levels of inbreeding ever measured in a vertebrate — a direct and expected consequence of a population confined for millennia to a space of a few square meters. The loss of hypoxia-related genes, even as the species lives in low-oxygen water, illustrates the paradox of local adaptation that does not prevent overall genetic erosion.

Not measured to date

The Devils Hole pupfish is presented as an umbrella species for protecting its unique desert aquifer — but the species has no described ecological role beyond its own habitat: no other wild species shares this 16 m² rock shelf, and no study measures what its disappearance would concretely change for the aquifer it is meant to symbolically protect.

Insufficient

Documentation

Last verified: August 14, 2026