Mediterranean Monk Seals Hide in Underwater 'Bubble Caves' to Avoid Tourists During the Busy Summer Season, a Study Suggests

Zafer Kizilkaya / Oregon State University via Flickr under CC BY-SA 2.0 When summer tourism heats up, Mediterranean monk seals take refuge in hidden underwater “bubble caves”—less-than-ideal hangout spots compared to their typically larger, more accessible caves. The discovery, described in a study published April 28 in the journal Oryx, deepens scientists’ understanding of the species’ behavior and habitat and could help inform conservation efforts.

Mediterranean monk seals are among the planet’s rarest pinnipeds—a group including seals, walruses and sea lions—with an estimated 444 to 600 mature individuals remaining in the Mediterranean Sea and small pockets of the Atlantic Ocean near northwest Africa. Their numbers are slowly increasing, but the species is still considered vulnerable by the International Union for Conservation of Nature and endangered under the Endangered Species Act.

These sleek marine mammals spend much of their time at sea, but they venture onto dry land to give birth and rest. Historically, they perched on open beaches for these activities. But after centuries of human persecution and disturbance, they’ve started hauling out in secluded caves instead. However, even then, tourists sometimes still get too close for comfort by entering the sanctuaries in search of the creatures.