The Russian military is enlisting special new recruits — five bottlenose dolphins — for combat training.

Russian Defense Ministry officials recently posted an online request to buy the three male and two female dolphins, and their solicitation drew a single winning bid from Moscow’s Utrish Dolphinarium. The mammals are to be sold to the military for $26,000, NBC News reported.

Both the US and Russia trained dolphins in the 1960s for tasks such as mine and torpedo detection. After recently gaining control of Ukraine’s marine-mammal training center, Moscow leaders decided to re-start their dolphin-warfare program.

Dolphins and seals “are being taught to search for sunken objects and to detect underwater enemy fighters and to defend warships,” according to state media.