In a finding that adds a new layer to the natural history of India’s east coast, researchers from GITAM School of Science, Visakhapatnam, have documented what they describe as the “first confirmed instance” of a horn-eyed ghost crab preying on a mottled lightfoot crab along the Rushikonda shoreline. The observation, recorded during a routine evening field visit in April, opens an unexpected window into the behaviour of a species long assumed to remain within sandy stretches of the intertidal zone.
The sighting occurred when Harish Prakash, a faculty member in the Department of Life Sciences at GITAM University, accompanied by researchers Abhisree MK and Rohan Kumar, noticed an unusual movement on the beach at low tide. What at first appeared to be the typical foraging activity of shoreline fauna soon revealed itself to be a rare interaction. A horn-eyed ghost crab, a species widely regarded as a keystone species and indicator of coastal health, was seen handling and consuming a mottled lightfoot crab. The latter is a species that occupies rocky crevices and does not ordinarily cross paths with its sand-dwelling counterpart.
Harish explains that the significance of this record lies not only in the act of predation but also in the geographical overlap it implies. “The horn-eyed ghost crab is generally restricted to sandy zones. Its possible presence within the rocky section of the intertidal area indicates a behavioural extension, likely tied to nocturnal foraging,” he says. According to Harish, this is the first documented instance of the species actively hunting this particular crab, which suggests a temporary merging of habitats where sand and stone occur in close succession.
The research team believes that such interactions could be limited to these transitional areas, where the rhythm of waves and tides creates mixed terrain. “Generalist predators, such as ghost crabs, tend to adjust their diet to the availability of prey, which varies across seasons and locations. The horn-eyed ghost crab is known for its adaptability, yet this instance of active predation on a rocky inhabitant stands apart from anything previously recorded along the Indian coast,” says Harish, who has been studying coastal biodiversity for the past couple of years.
A horn-eyed ghost crab
Ghost crabs play a crucial ecological role in sandy intertidal environments. Belonging to the genus Ocypode, they influence the distribution and abundance of smaller organisms through their feeding habits and the deep burrows they build. These burrows also shape the physical texture of the shore. Their pale bodies blend easily with sand, a feature that, along with their swift movement at dusk and dawn, has given rise to their common name. Six species of ghost crabs have been reported along the Indian coastline, and at least three of these have been observed at Rushikonda Beach, including O. brevicornis, O. macrocera and O. cordimanus.
Apex predator
While the species of horn-eyed ghost crab has traditionally been described as a scavenger, studies over the past decade suggest that many populations act as apex predators within the intertidal food web. They have been recorded hunting clams, snails, worms, isopods, shrimps and a variety of insects. In some regions, they feed on the eggs and hatchlings of birds and turtles. They also prey on other crabs, including smaller hermit crabs. The new observation adds another dimension to this growing body of knowledge and suggests that the species may be more flexible in its foraging than previously understood.
The GITAM team points out that such unexpected interactions can arise from shifts within the intertidal ecosystem.
The team of researchers from GITAM School of Science in Visakhapatnam.
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SPECIAL ARRANGEMENT
“Pollution, changes in sediment distribution, rising sea temperatures and altered tidal patterns may prompt species to explore new microhabitats in search of food. This single event cannot be interpreted as a long-term ecological shift, yet it raises questions about how coastal species respond to environmental disturbances,” emphasises Prakash.
He adds that sustained observations across seasons will be essential to understand whether this predation was an isolated event or part of an emerging pattern. He notes that the coastline of Visakhapatnam, with its pockets of sandy beaches interwoven with rocky shelves, offers a distinctive environment to study such transitional interactions.
The encounter was documented carefully, with the team ensuring that the animals were not disturbed. Only a brief beam from a headlamp and a single photograph were used to record the moment. Since the observation involved no manipulation of the animals, no ethical approval was required for the study.
The finding has been published in the November edition of the Journal of Threatened Taxa, a monthly scientific journal brought out by the Wildlife Information Liaison Development Society based in Tamil Nadu. The paper situates the observation within the broader context of intertidal ecology and stresses the need for more field-based studies along India’s east coast, where documentation of predator-prey interactions remains sparse.
The researchers believe that such insights, although based on individual events, are vital to understanding how coastal ecosystems function. Predator-prey relationships reveal which species dominate, how resources are shared and how small disturbances can create ripple effects across the food web.
According to scientists and researchers, observations like this help to build a clearer picture of how intertidal communities respond to environmental changes, both natural and human-driven.
Published – December 04, 2025 10:16 pm IST
