Do you remember that 'BLACK DAY', in May 1975, when the contents of DCI [RN]T [meaning temporary] 300/75 came into force?
No, I don't expect you do, but for many of us it was bad news.
Stories abound about pets in ships and submarines, in peace time and in all out war, calm days and storm force 10 days, and how they were loved and cared for by many in the crew, although it has to be said, that these pets had their favourites, snuggling up to sailors they trusted [and loved] more than any other.
The edict ordered that ALL pets notwithstanding, should be landed on UK terra firma before sailing and none should be brought back from foreign visits in lieu.
The reasons was obvious and of course correct in that it protected our animals and ourselves from the ravages of that dreadful disease rabies, but the landing was not to be a temporary expedient, but a permanent situation. The landed animal had no home, care or love when the ship was away at sea, and thus the landing had to be made permanent and a new owner sought before sailing. Some of the animals went to the families of crew members, so when on leave, sailors were reunited with their much-missed pets. The admiralty didn't want ship's berths to be the waiting areas for lots of Greyfriars Bobbies, and policed the ban with authority. Eventually, the ban covered all animals/pets onboard, even those which couldn't go ashore on a foreign visit, so included every living creature that dear old Jack had collected on his travels. Many animals had to be sold-off to pet shops and the like, but hopefully only a very few had to be destroyed. That's not the way the navy or us Brits work.