The US Navy has revealed that some of the dolphins it has trained to track down mines are to be replaced by robots.
Unmanned, torpedo-shaped devices which are 12-ft long (3.6m) have been developed to do the work of 24 of the 80 mammals which are currently used by the military as part of a programme dating back to the 1950s.
The dolphins are trained over a period of seven years and rely on their sonar to detect mines in shallow water, in deep water when they are secured by tethers and at the bottom of the sea where sediment and plant growth can hide the devices.
Navy officials say the new machines can carry out the same duties as the dolphins, but are available to use much more quickly.
The robots will enter service in 2017 when some of the animals will be moved to work in port security alongside the military's sea lions.
In recent years, dolphins have been deployed to places such as Iraq and Bahrain to look for mines.
They are transported from US bases aboard Navy ships in large moveable pools.
The military's \$28m (£17.5m) marine-mammal programme currently uses 80 bottle-nosed dolphins and 40 California sea lions but it once also included killer whales and sharks.