Little-known underground eels in India mountain range exhibit ‘bizarre’ behavior
The Western Ghats in southern India is an ancient mountain range stretching nearly 1,000 miles.
Older than the Himalayas, the Western Ghats are of “immense global importance” for their rich biodiversity and are home to hundreds of species — many rare or threatened — found nowhere else in the world, according to UNESCO.
Despite its ecological significance, much of the region has received little scientific study, particularly its subterranean habitats.
A new study, published Aug. 11 in the journal Vertebrate Zoology, sheds light on one of the region’s rarest creatures: aquifer-dwelling eels.
These animals, often stumbled upon accidentally, are “poorly known and incompletely documented,” researchers said, adding that most of them are known only from their original description when they were first discovered.
The team focused on two groups of subterranean eels: Ophichthys, known to be fossorial and possess small eyes, and Rakthamichthys, which are are “blind,” or eyeless, and primarily inhabit aquifers, according to the study.
Perhaps the most significant discovery was 11 distinct lineages of Rakthamichthys eels, according to the study. This means that although all these specimens bear “remarkable” physical similarities, they are genetically distinct, suggesting at some point, circumstances forced them to evolve separately.
Additional research is required to confirm if they represent new species, according to the study.
Researchers also noted a “bizarre distribution pattern” among the Rakthamichthys species, with some existing in a very narrow range of microhabitats, while others were widespread, according to the study.
“Most subterranean habitats along the south-west coast of India are under severe anthropogenic threats,” researchers said.
For groundwater-dependent species that could disappear before they’re even identified, the need for further additional study and conservation efforts is urgent, according to the study.
The research team included Rajeev Raghavan, Remya L. Sundar, C.P. Arjun, Arya Sidharthan, Nithinraj Panangattu Dharmarajan, Appukuttannair Biju Kumar, Siby Philip, Anvar Ali, Mandar S. Paingankar, Glavin Thomas Rodrigues, Ralf Britz and Neelesh Dahanukar.
The team dedicated their research to the late Francy Kakkassery of St. Thomas College in Thrissur, India “for his interest in these enigmatic eels, and for inspiring and motivating many of the authors of this paper to document and undertake research on these poorly-known taxa.”
This story was originally published August 20, 2025 at 2:58 PM with the headline "Little-known underground eels in India mountain range exhibit ‘bizarre’ behavior."
