Three whales and a dolphin have been found beached in recent days.
In the latest discovery, a male sperm whale, pictured, was found stranded on Omey Island near Cleggan, Co Galway.
The deep-water adult mammal was already dead when it was washed up, with the skin shed and its lower jaw broken.
The Irish Whale and Dolphin Group (IWDG) last night said it was relatively common to have strandings, with between 140 and 150 reports each year.
IWDG co-ordinator Simon Berrow said: "Chances are it died offshore and got washed in with the wind."
Mr Berrow said the IWDG had also recently received reports of a bottlenose whale found on White Strand in north Clare, a pilot whale on Fintra Beach in Donegal, and a dolphin in Silverstrand, Galway. All were dead when discovered.