27-05-2025
Cavers find massive creature on remote island for first time in decades. See it
Cavers shined their flashlights along a rock wall of a remote island in India and illuminated a massive creature. Over 150 years of scanty records, a devastating tsunami and failed wildlife searches led up to this moment: the island's first sighting of an at-risk species in decades.
A team of scientists visited Car Nicobar Island in April 2024 and started poking around 'a small cave,' according to a study published May 26 in the peer-reviewed Journal of Threatened Taxa. To the researcher's surprise, they found a large crab tucked in one of the rocky crevices.
Photos show the blue-gray crustacean, identified as a coconut crab or Birgus latro.
Coconut crabs are 'the largest land arthropod,' a group that includes spiders, crustaceans and insects, the study said. They can reach over 3 feet across, weigh up to 11 pounds and live up to 60 years.
Although 'distributed widely across the Indo-Pacific region,' coconut crabs are considered a vulnerable species, threatened by human activities and 'geological events, such as tsunamis,' researchers said.
On Car Nicobar Island, coconut crabs faced both of these threats.
In 2004, a tsunami 'extensively devastated coastal habitats across the Andaman and Nicobar Archipelago,' an island chain that includes Car Nicobar, the study said. As part of the post-tsunami recovery efforts, scientists traveled the archipelago in 2012 and 2023 surveying what plant and animal life had survived. Coconut crabs were found on several islands — but not Car Nicobar.
Until recently, Car Nicobar's only confirmed sighting of a coconut crab came from 1874, the study said.
Researchers described their April 2024 sighting as 'incidental' and not part of a larger surveying project. The coconut crab they photographed was an adult male, weighing about 2.6 pounds. Its full size is unknown, but its body measured roughly 5 inches long.
The team saw a pile of coconuts nearby and human trash, food sources that 'may have attracted' the crab, the study said. However, 'discarded food packaging and plastic waste pose significant hazards, as crabs can become entangled or ingest harmful materials.'
Finding coconut crabs 'remains challenging due to the cryptic nature and nocturnal behaviour of the species,' researchers said. 'For species such as coconut crabs, which are rare, elusive, or in challenging environments, incidental sightings provide valuable insights into the species' presence, behaviour, or habitat preferences that might otherwise remain undocumented.'
Car Nicobar Island is part of the Nicobar Archipelago, an island chain off the eastern coast of India and near southern Myanmar, southern Thailand and northern Indonesia.
The research team included Mayur Fulmali, Dhanesh Ponnu and Nehru Prabakaran.
