The precise threats facing the endemic predatory shrimp are unknown, but its extremely restricted range is a considerable cause for concern. In 1976, three mangrove trees were found in the larger pool, in a straight line as if they had been deliberately planted. While the pools are difficult to get to, it has been noted that locals would occasionally visit them to collect shrimps to feed their aquarium fishes, and may have planted the mangroves. These were perceived to threaten the shrimp population so were promptly removed, but human disturbance and invasion by alien species remain significant threats (3). Furthermore, it has been argued that the similarities between all Procaris species, and their distribution only in obscure marine caves and pools that have changed little over time, indicate an extremely slow rate of evolution. The suggestion is that Procaris and its predecessors may have been more widely distributed in the past but can now survive only in cryptic habitats removed from the sort of human and environmental pressures that necessitate evolutionary change (2). Thus, if this species’ small, restricted habitat should change, it is unlikely that it could adapt fast enough to survive.