The US Navy used dolphins in the Gulf War. Dolphins were used to help protect the United States’ 7th Fleet during the Vietnam War. Dolphins have been used by NATO to detect mines and shells in the Baltic Sea and off Norway.
The Russians also have a program with marine mammals:
“Marine mammals can be used to protect strategic installations and in anti-terror operations, Academician Gennady Matishov, the director of the Murmansk Marine Biology Institute, told Interfax.
“In our opinion, the use of marine mammals is a very promising aspect of programs to enhance the protection of coastal installation from terror attacks and in monitoring the underwater situation. Marine animals possess a unique ability to locate underwater biological and technical objects in the environment of natural and artificial noises, and in conditions of complex seabed features,” he said
Read more here: http://www.interfax.ru/e/B/0/28.html?menu=1&id_issue=11728546
But the practice is opposed by the Cetacean Society who wrote with respect to the use of dolphins by NATO in 2001:
“The dolphins will locate with echolocation a small fraction of an estimated 80,000 mines and other munitions, and attach marker buoys for retrieval… The U.S. Navy is proud to show what the dolphins can do… [but] the Cetacean Soceity thinks it is immoral exploitation, similar to experimenting with unwitting servicemen exposed to deadly diseases. It makes us wonder sadly what we don’t hear about.”
Other animals have been used in wars. For example, 8 million horses died during WWII.
Is it justified to use animals in warfare?